Which symptom is MOST noticeable on your dirt bike? Learn how to easily tune the air/fuel screw in just a few minutes: 2 stroke - motocrosshideout.com/carb/ 4 stroke - motocrosshideout.com/fuel/
2024 YZ85 big wheel starts great hot or cold Right before power band full throttle it coughs bad 1 or 2 times every time hot or cold then goes. Yamaha usually sends them rich. I dropped the needle up to 4 notches and still coughs hasn't changed the cough. 3rd notch drop looked good on the plug medium brownish. They come with a 10 heat range plug I'm wondering if it's too cold having a hard time igniting fuel? Some times in Power band it crackles a little bit with some power loss. Tried air screw from 1/2 turn out to 2 turns still coughs before powerband. Yamaha says 30:1 I run closer to 25:1, older bikes used to run 20:1 Could it be just too cold of a plug having a hard time igniting the mix fuel?
Also it has fouled 2 plugs in less than 3 hours of riding bike would still run but no power and just sputters and crackles new plug goes back to running descent. The plug check and watching the smoke it doesn't seem rich, it seems close. Could they be fouling from being to cold heat range plug #10 having a hard time burning then overwhelmed with fuel and fouls? After it coughs before power band it usually screams feels good most of the time.
Changing the plug to a different heat range would just be a band aid fix. If it's not smooth when you hold it WOT, then I would go down one on the main and see what happens. Make sure you have a new spark plug and it's fully warmed up before testing.
If the needle hasn't made much or any difference, I would put it back in the stock position (middle) and then drop the main down a size or two and see what happens. Have you downloaded my free air screw tuning guide? (Link in description)
They actually were. I thought I was running rich, but because of his "ridiculous" sound effects, I now know I'm running lean. Sometimes acting ridiculous is the best approach.
This is super helpful and I loved the sound effects. It was entertaining but worked perfectly to explain the symptoms. I kind of want to make a video just with the engine sounds!
This definitely helped me today. Glad you made the sounds and played short clips of the engine sounds. I got the moto fixed and now we all go BRRAAAPPP!
I'm impressed ! I watched your video more or less just to see what you get WRONG.... but you didn't and for a young guy to have that good of an understanding of the internal combustion machines is amazing ! I've used those aforementioned symptoms to trouble shoot carb issues for over 5 decades .... what will throw you for a loop is having a faulty ignition system that looks like a carb issue ! and that happens all the time. especially with older bikes ! ......so if you've been through the carb several times but the bike is struggling to get power at top end.... suspect that the ignition system is faulty in one way or another. older points systems had the condensers go out all the time but still run...just not run great! newer electronic ignition systems are virtually bullet proof, but they do fail occasionally usually they just stop sparking the plug completely.... but not always and they can be a real Bitch to figure out ! ....you explained hainging idle very well but can be just an idle that is high that takes a while to come down.... My 250 Ninja suffers from this as we speak.... just haven't got around to tweaking the air screws .... I also bought a thumb screw for the air mixture screw for the XR650L that I take to high altitudes every once in a while.... because when set to 4k ASL at 8K ASL it will not re start.... twist the air screw about 1/4 turn and it fires right up ! LOL
I'm noticing a slight sputter once I reach crazing speed during the summer heat. Give it gas and intakes off, lean the jets some and get rapid backfire.. carbs..
Hello Greetings from Argentina, I have a 2-stroke motorcycle with a racing exhaust and I have a problem with the carburetor configuration. I can't find the right one. The spark plug has a reasonably good color and there are no air intakes. The motorcycle feels rich at 1/4-1/2 throttle, I tried touching the needle but it only works well, very hot. I have a question, I tried to progressively accelerate the bike in idle and it revs correctly up to half throttle, where suddenly it accelerates to the maximum. Is this normal?
My bike is feelings like its not even hitting the rev limiter the rpm fluctuate just slightly befor the limiter and causes crackling and poping when i over rev it, its not touching the rev limiter . Can you please help with the reason i am unable to understand...its just 2 months old bike.... this problem came when i got half lower engine case changed (connected to engine oil filter ) the engine sound is also more bassy and burping like sound... the rpm is stable at idle and not having any problem in reving but problem comes at higher rpm only
what about the same elevation but different air temperature outside, like when the bike runs good in warm weather but worse in cold, is that even a thing? assuming that engines are heated up to spec
Great question, and yes that certainly makes a difference in jetting! Engines tend to run leaner when it's colder, so richening it a little should help.
Gotcha, what's holding you back from tuning it yourself, if you don't mind me asking? Also, do you know what your mechanic typically charges for that kind of work?
My 50cc two stroke is happy when I give it full gas and has good throttle response but when I give it like a quarter or half of the throttle it really ''stutters'' so it like rititittititi bogghh, but when I open the throttle more it's running nice. When I close the throttle at high rpm's or after accelerating it takes a while to go to idle rpm's so its not getting fuel or oil so I think i'm destroying my engine. It is a steel cilinder that has ran for about 150 to 200 km's so It's quite new. Had a lot of trouble getting it to idle right without changing jets, had to turn down air screw like 2 full turns for it to not revv like crazy on cold startup. But now having a hard time getting it to idle just a little higher. Anybody any idea's if it's running lean or rich? And what to do about it?
I have Hero Maestro edge scooty, when i was setting mileage, through carburettor mixture screw, my scooty spark plug looks like wet and little blackish,, i want to ask you It's a richer side or leaner side
I have a 2 stroke 73cc aluminium kit. and its smoking a lot on wot, but I cant understand why because it's lean. the spark is brown but more on the lean side. I was running 122 main jet, after that, I installed 115 and it was SUPER LEAN and it still made a cloud of blue smoke. Now I'm running a 118 main and its still smoking. I have tried everything, like taking of power jet, different oil, other gasoline, different air temperatures, spark plugs, different oil mixtures, changing needles, needle clips, different carb positions and a lot more.
It's liquid-cooled. At the moment I have a 24mm carb and it idles a lot better but still smoking on WOT but a lot less. It acts lean but still smoking. The headgasket is not leaking and the gearbox oil level is normal. And does not smell like gasoline
I've followed your guide, and much appreciated, it's quite addictive aiming for the sweet spot and have helped 2 friends get their pilot set up and running better. For my own bike I have the carb dialled in as good as I can, mainly on feel, taking the bike out for a good run. But I've gone up on main jet and it pulls so much better mid but now it seems not to rev out as much at top. Maybe over thinking this, but can running too rich improve mid range at expense of top end, evrything I'm.rrading is saying rich improves top end.
Thanks for sharing Scott - I'm glad you found my guide helpful! That's a good question. From my experience, you shouldn't have to sacrifice top-end for midrange torque based on jetting. I like to lean out the main jet for top-end/peak HP until it starts losing power or bogs and then go back up (richer) 1 or 2 sizes.
I have a 2003 Honda xr70r I’ve tried to adjust the idle but the bike wont idle without me hitting the gas so if I let off the gas at a high rpm and it gets into the low rpm it shuts off and doesn’t idle does anyone know how to fix this?
I have a Ktm 85sx with a smart carb. It takes multiple kicks cold, takes a while to warm up, it bogs low in rpms and when I rev it a quarter throttle after it warms up I need to kill it because it wont drop down to idle quickly. But Im just not sure if this is an air leak or if its running rich or lean
It's definitely running lean (too much air). However, it's hard to know without more info if it's lean from jetting or an air leak. I would try tuning the low speed circuit first (not sure what the smart carb has in place of an air screw).
Hi, What it could be if my bike randomly lost power and shots down. At that moment cant start bike, but after 3-5 min it starts ok. When bike goes in neitral gear, Power comes biger and biger and biger... like slowelly increasing rpms by itself.
Hmm, sounds like a possible electrical problem if it gets worse when hot? Perhaps a broken or loose wire somewhere. Increasing RPM also sounds like a possible air leak. Make sure the carb clamps are snug and the intake/air boot don't have any cracks.
hello i got a question my rmz 250 runs good but when i ride at like half thorrtle its like hitting the rev limiter but if i keep giving it more thorottle it goes away any idea if its running to rich or lean?
I’m trying to fix a 2003 XR 70R that hasn’t run in about 12 years and the bike is struggling. I’ve put a new carb in it and the bike starts however the idle is often way too high, sometimes even idles at max rpms. Other times the bike will idle much lower and closer to where you would like it to idle at, however when this happens it will start idling quite high randomly and go back down after a bit. There is also sometimes where the bike will smoke a lot, often when the idle is really high. I can’t warm it up because the idle is way too high for a cold start and the adjustment screws don’t seem to change anything with the idle. Does anyone how I can go about fixing this
I’ve got a 4 stroke that I would say is running a little rich. But my biggest issue is flame outs or stalls. I’ve only ever rode 2 strokes and I’m wondering how to fix it
Hey Justin, flame outs are often caused by lean pilot circuit jetting or a light flywheel weight. Can't remember if the lectron has a fuel screw, but I would richen that and see if it helps (always test when the engine is fully warmed up).
@@MotocrossHideout I would adjust it but it has some of the signs of running rich like fuel smoke while idling and giving it gas but I’ll do some adjusting on it and see what happens thanks for the help
think i have watched this video at least 20 times already so helpful! wish i could remember half of it 🤦♂ Can we get a 2smoke special after the trail vids
1980 PE 175 2 stroke. When starting it takes 6 -8 kicks with choke on. When it starts it will rev high for many seconds. It is like my kicks are filling up the the engine with fuel then it starts. When I stop the bike I will turn off the gas and run the fuel bowl empty. I am familiar with jetting and the float level has been set. Any thoughts?
Revving high right away is typically a lean symptom. Either not enough fuel or there's an air leak around the carb/intake. Check for loose clamps or cracked manifold, then move to jetting. Let us know what you find.
I have both symptoms… i can start without choke easy but when i accelerate then it boha down and after bog its have power asf … i have beta rr 450 2006
Hard to know without more info. The the chain and sprockets straight and in good condition with proper tension? If everything external is good on the bike, then I might want to pop the clutch cover off to make sure nothing is loose or broken. Let us know what you find!
just picked up a yz250, any recommendations on what ratio to use? It's not a stock bike, has race modifications done. I've never had to mix gas and oil before so pretty nervous 😅
@@Yz125-z4l Interesting. If it smokes a lot more after a top-end rebuild, that would make me think that something in the top end isn't right, such as the piston ring not sealing. I know that's not what you want to hear, but it's not the first time I've heard of "rebuild" problems. I would probably do a compression test to see what it's at. Let us know what you find.
I’ve got a bike that runs fine down low but full throttle high load it has no power and doesn’t accelerate. Ive cleaned the filter changed to new plugs and cleaned the carb,( I may need to clean the carb again). This bike has ran great all summer so I’m not sure what’s going wrong now. The bike usually has crisp throttle response off idle but some times on snappy throttle twists it stumbles at first.
Hey Evan, does it happen more on hotter/high humidity days? It sounds like it might be running rich (if it's sputtering), which is typical on hotter days. If the compression is good, you might need to go smaller on the main jet (if it sputters at WOT). Let us know what you find out, as well as the bike you're tuning :)
Yeah, that's why spark plug reading isn't always accurate. Does it bog when you turn the throttle wide open? That could be lean on the main jet, while the black plug is caused by rich on the pilot jet.
@@MotocrossHideout it is bogging when i turn the at full throttle. The bike is not moving the engine is like its going turn off. But when i am on drive. Just like your example on number 6(bog while accelerating)
Yeah that sounds to me like a lean main jet (too small). I'd go one or two sizes bigger and see what it does. Not sure what bike it is, but some bikes also don't respond as well when you "whack" the throttle open, especially if it has an older carb without an accelerator pump.
my 4 stroke especially in first gear likes to jump like cut in n out when i get on the gas and when i hold it like half throttle it just sounds horrible
I have a yz 85 bored to 105cc used the same jets and was fine,then I installed vforce4 reeds and rebuilt the carb with the same size jets but new ones, now the bike doesn’t want to start from cold with or without the choke without giving some throttle, even when engine is warm it won’t start without throttle and when I give it some revs and let off,the engine wants to cut out, also turning the idle screw doesn’t seem to change the revs, and has a minor bog from 0-1/4 throttle but once hitting the bands it runs fine, any idea what this could be?
@@MotocrossHideoutyes the air screw didn’t seem to make a difference so I’m going to try a smaller pilot jet and see if it’s better or worse thank you, I wasn’t sure if it’s too lean or rich
Bike doesnt need choke to electric start and fires within the first 2 cranks. Bogs hard when i pin the throttle but i can roll in and have good throttle response. I dont get any sputter or hanging idle. It gives me lean and rich symptoms
Hard to diagnose without more info. What bike? Is engine fully warmed up? What throttle position does each symptom happen? Has it always done this or has it gotten worse?
@MotocrossHideout yamaha ttr-230. Moved the bike from sea level to about 7000. Jetted Down from a 117 to a 106. If I pull the scree almost all the way out it runs better with a huge bog on initial throttle but will pick up. Today I moved up to a 110 and was able to put the screw in about half way. Still a bog in the start with both engine cold and hot. I've been chasing it for about a year now
Okay, first you need to get the fuel screw properly tuned. The fuel screw is on the bottom of the carb in front of the float bowl. It controls 0-1/4 throttle position. That will tell you if the pilot jet is too big, small, or just right. Then the main jet controls roughly 3/4 to wide open throttle position. Always make one change at a time and only when the engine is fully warmed up.
@@jaredradison8372 Okay, always make one change at a time. Get the fuel screw/pilot sorted first - that's from idle to 1/4 turn throttle position. If it's bogging (engine dying) at WOT, the main jet is probably too lean/small still. Don't make changes if the engine is cold/not fully warmed up.
hey guys, i need help, i was riding completely fine and when i stopped it stalled. I kickstarted it and it was stalling when i didnt put a lil bit of throttle. So i quickly went home and when i was dricing home i figured out that my gas is bad. When I held the throttle for a while and then let it go, it held on for a while. When I just moved the throttle, the throttle stayed for another 0.3 seconds, which didn't happen before.
That's definitely one symptom. That usually means it's running rich, which could just be the jetting, but it could be a very dirty air filter or perhaps a worn out engine that's running low on compression.
@@MotocrossHideout would it feeling like it's "chugging" on idle in 1st gear tie in with it being "too rich"? Im praying it's not a worn engine, I made sure the carb and air filtration system was perfect before I put the carb back in. It's a 96' vulcan750, and I got it with the carb detatched because my dude rebuilt it but couldnt figure out how to put it back in
@@MotocrossHideout Crap, oh well 🤷♂️ Now that I think of it, I should probably re-tune that carb before I start asking about idle on 1st feeling like it's got too low rpm Thanks for the replies!
Mine does the ritch thing under half throttle and the lean thing over half throttle idk what to do, i cant even drive it over half throttlw it just dies and it sputters under half pls send help🥲
I have a klx140 with bore up kit 66mm, cam lift, exhaust. it runs great at 3/4 to full throttle but in technical slow section specially rocky section its like its coughing/sputtering i'm using 28mm carb with 38/120 jet 1st clip on neddle. is the pilot jet too rich? it gets worsen if I pull the choke from 0-1/4 throttle.,by the way usually running at 200-800 ft.
That sounds rich to me. Not sure which 28mm carb you're using, but have you tried leaning out the air/fuel screw? Grab my free guide to learn how to do it in just a few minutes to know if your pilot jet is too big.
There is a map that shows the overlap of different systems in the carb. Find that and specifically dial in the area that’s affected. I found out when you understand the concept of the systems they each have to work well for that smooth linear operation ir you get what you have. Sounds rich too. Could be needle size and placement as well as air fuel. Is screw before body of carb is adjusts fuel is after main body (float bowl) and it’s closer to cylinder head it adjusts air. Look for that breaks it all down. I think it the RD jet kids or??
@ basically I bought this off Facebook It was idling good but the oil was very dirty so I changed it and added 700ml 10w-40 semi synthetic oil and now the exaughst gets very hot right after starting it
@@aayantheangler7101 Exhausts normally get very hot. If it's glowing red, it's because it's sitting too long or the pilot jet/mixture screw is too lean, typically.
Great vidoe man but i still can't figure out whats wrong with mine. I have a Crf250X, it starts like it should. When i give it some throttle the rpm stays high and wont settle to normal. When i pull the choke out and back in it goes down to normal. But again when i throttle it stays high. When im in gear i can let the rmp go down by pulling up with only the clutch. If the bike stalls of I want to start it when it's warm, it won't start and eventually drags the battery empty. I played with the air mixture screw and stationary idle screw but I can't figure it out 😬Maybe I did something wrong. Could there also be something wrong with the throttle body you think, like scratches or false air?
That sounds like a hanging idle, which is a lean condition, usually caused by the fuel screw/pilot jet being too lean or an air leak. Make sure the carb clamps are tight, there's no cracks in the intake/air boot, and that the fuel screw has the proper o-ring/washer on it so no air is leaking by. If it's always done this, then I'm guessing you just need to richen it up. If it's a new problem, the pilot jet might be dirty and need to be cleaned or replaced - assuming there are no air leaks. Let us know what you find, Wesley!
You should have received it within a few minutes of signing up. Check your spam folder in case it went there. If it's not there, just reply to one of my emails and I'll personally send you the guide. -Kelley
Hey, got a strange problem i can tune the jets up or down even to where its perfect and the plugs golden, yet when going over 80ks so 4th gear and up it will cut out after a few seconds of throttle its a old bike ts250 but any help would be appreciated, thanks!
@@MotocrossHideout Thanks mate and no tacho on mine atm but its probably rich yet when i downsize the main it cuts outs as well, but i know its not redlining cause it used to work fine, so a bit stumped
@@MotocrossHideout Oh yes it makes a lot of sense. But my question is if it results in the engine overheating because of the increased friction of the clutch? I mean I thought the clutch was located more near the tires and not the engine. If that is correct, then how the clutch would produce more heat for the engine?
Crusty as in the spark plug is black? I would try going down on the main jet and see what happens. Don't change the oil mixture - just do one thing at a time so that you know what made the difference.
My 4 stroke 250cc quad does frive alright has alot of power but when decelerating i hear alot of pops from the exhaust,i thought that might be becouse of a to rich mixture but i have no problems or signs whatsoever
@MotocrossHideout gotcha! Thank you for all that you do! I have so much more confidence and a much better rider in just a week's time by watching and paying attention to all your lessons and advice. I don't want to find myself overly confident and always maintain a respect for the machine. I am so in love with my bike! I'm going to always be good to her, and she'll always be good to me.
So I kind of have symptoms of both. Easy start. Bogs and dies with throttle. Hanging idle. Poor throttle response. What should I be looking at next? It’s a 90cc 2 stroke atv. Kids were riding fine one day and just started acting up, hasn’t been the same since. Carb rebuilt, new jets and all. Also has new oil pump.
@@MotocrossHideout so far I haven’t found any air leaks. Seems to idle best with air screw around 1 turn out but still bogs out with throttle. Any idea what could cause it mid-ride?
@@MotocrossHideout so, its mostly 0-1/4, almost immediately. when I can get it to rev, I can tell its cant go full throttle. top end rebuild kits are fairly inexpensive on these, could that solve it?
Mate I need some help, my bike starts just fine with one kick in lower elevation, but in higher elevation it can't do that anymore, It's hard to start, when I check the plugs, the color of it is grayish (I checked it in lower elevation), what seems to be the problem here mate? It seems that the RPM runs too low in higher elevation that's why It doesn't start easily, but if I bring it up, the idle in lower elevation would be too high
Good question - that's a very common problem with carbureted bikes when changing elevation. When you go higher, the air is less dense and it will make your bike run richer, so you'll need to lean the jetting out at a higher elevation, and then richen it back at lower elevation. Start with the air/fuel screw. Does that make sense?
What’s your recommendation when you have symptoms for both rich and lean? My bike is getting super hot in a very short amount of time (before actually riding). It starts really easy when cold with or without choke and revs really high until bike warms up and then the revs die down and even out. I’ve just rebuilt the top end after the motor got that hot the piston seized the inside of the barrel. After about 10 minutes of riding.
I have a DR350SE with a tm33 pumper carb. At idle, it has a bog when quickly snapping the throttle, and I can't figure it out. I've tried changing jets and would always end up too rich, and I've checked the pumper needle multiple times.I even went as far as installing a wideband O2 sensor in the exhaust. The tm33 pumper carbs don't have adjustments on the pumper, it's just a rod. The bike runs great other than that, I've been trail riding with it for a year. If anyone has any ideas, I'd be willing to try them. 😊
@@MotocrossHideout It's when the throttle is closed and I quickly open to wide open it will bog. Which is lean, I think. I've gone up a main jet and it spits and sputters at 3/4 - full throttle and the wideband gauge is pegged in the 10s full rich. So I changed it back. I've heard it's hard to dial these pumper carbs in on a dr350.
If it's a 4stroke and blows white smoke it's a problem with oil in the combustion . Not good. Engine worn out. Brown or black smoke is unburned fuel. A mixture problem .
Hey my bike backfires and shoots a flame about every 7 seconds when i accelerate, its fine and feels good untill about 60% throttle then it starts to happen. It also bogs at super low rpm if i just rip the throttle. Any tips/ideas ?
Can some one please help me if i gou past 3/4 of throttle my bike starts surging the whole time it is a 4stroke carberator engine what can be the problem
@@MotocrossHideout I found the problem I lost spark on the coil and spark plug wire and I adjusted the float level it is now revving out after I bought new parts
What’s a symptom of 250f feeling slow in top gear? Was riding with my buddy who has a 450 and felt like I was topping out at like 50mph. Possibly the sprockets? It is a used bike. Seems to have plenty of power was just suprised thought the top speed would be more
My yz85 fouls plugs every ride I have an fmf shorty on it with I think rich jetting from the guy I got it from and I ordered stock and a size down for each Jett. Does that seem reasonable?
Yeah, stock is a good starting point, but they often tune the race bikes a little on the rich side from the factory. Start with the air screw - grab my Free guide if you haven't already;)
![How To Tell If Needle Is Rich or Lean [Jetting Symptoms & Sound]](http://i.ytimg.com/vi/i-o7OpLc8ps/mqdefault.jpg)
Which symptom is MOST noticeable on your dirt bike?
Learn how to easily tune the air/fuel screw in just a few minutes:
2 stroke - motocrosshideout.com/carb/
4 stroke - motocrosshideout.com/fuel/
2024 YZ85 big wheel
starts great hot or cold
Right before power band full throttle it coughs bad 1 or 2 times every time hot or cold then goes.
Yamaha usually sends them rich.
I dropped the needle up to 4 notches and still coughs hasn't changed the cough.
3rd notch drop looked good on the plug medium brownish.
They come with a 10 heat range plug I'm wondering if it's too cold having a hard time igniting fuel?
Some times in Power band it crackles a little bit with some power loss.
Tried air screw from 1/2 turn out to 2 turns still coughs before powerband.
Yamaha says 30:1 I run closer to 25:1, older bikes used to run 20:1
Could it be just too cold of a plug having a hard time igniting the mix fuel?
Also it has fouled 2 plugs in less than 3 hours of riding bike would still run but no power and just sputters and crackles new plug goes back to running descent.
The plug check and watching the smoke it doesn't seem rich, it seems close.
Could they be fouling from being to cold heat range plug #10 having a hard time burning then overwhelmed with fuel and fouls?
After it coughs before power band it usually screams feels good most of the time.
Changing the plug to a different heat range would just be a band aid fix. If it's not smooth when you hold it WOT, then I would go down one on the main and see what happens. Make sure you have a new spark plug and it's fully warmed up before testing.
@MotocrossHideout ok my needle is all the way down, when I drop the main size I should put the needle all the way up bottom notch?
If the needle hasn't made much or any difference, I would put it back in the stock position (middle) and then drop the main down a size or two and see what happens.
Have you downloaded my free air screw tuning guide? (Link in description)
The sound effex was the best part of the video. 🙂
Haha, thanks. I hope it wasn't the only good part 😅
It was the effect but you was spot on. Thanks 4 the video very useful.
They actually were. I thought I was running rich, but because of his "ridiculous" sound effects, I now know I'm running lean. Sometimes acting ridiculous is the best approach.
This is super helpful and I loved the sound effects. It was entertaining but worked perfectly to explain the symptoms. I kind of want to make a video just with the engine sounds!
No joke the sound effects helped ❤️
his sound effect were dead on
Frfr
Right?!... 💯
Agreed 👍 very helpful video/channel I’ve been coming back too
well sounds like my bike is too lean and too rich
😭😭😭
Exactly the Same
Same 😅
I was thinking the same thing lmao. It is so fun getting that air/fuel ratio just right
Means it’s running just right😂😂😂
Speaking a language only motorcycle owners know and it makes sense
Lol, dude, the sound effects were both r*tarded and completely spot-on. Thanks, I now know I'm running lean, and not rich.
This video helped me sooo so much thank you. Sound effects really helped 😄
Glad it helped - thanks for watching, Ivan!
Thanks for the great video, spot on sound effects!
Haha, I try! 😂 You're welcome, and thanks for watching, Bob!
This definitely helped me today. Glad you made the sounds and played short clips of the engine sounds. I got the moto fixed and now we all go BRRAAAPPP!
Great to hear - thanks for watching!
I am tuning a 1984 Honda ascot vt500ft. The video was easy to understand. Thanks for keeping it simple.
Don't ride motocross, but I was seeking information for a motorcycle. Subscribed just for the sound effects because it actually helped a lot 🤣
Ha, thanks for watching! If you know anyong getting into dirt biking/trail riding, please share!
I'm impressed ! I watched your video more or less just to see what you get WRONG.... but you didn't and for a young guy to have that good of an understanding of the internal combustion machines is amazing ! I've used those aforementioned symptoms to trouble shoot carb issues for over 5 decades .... what will throw you for a loop is having a faulty ignition system that looks like a carb issue ! and that happens all the time. especially with older bikes ! ......so if you've been through the carb several times but the bike is struggling to get power at top end.... suspect that the ignition system is faulty in one way or another.
older points systems had the condensers go out all the time but still run...just not run great!
newer electronic ignition systems are virtually bullet proof, but they do fail occasionally
usually they just stop sparking the plug completely.... but not always and they can be a real Bitch to figure out ! ....you explained hainging idle very well but can be just an idle that is high that takes a while to come down.... My 250 Ninja suffers from this as we speak.... just haven't got around to tweaking the air screws .... I also bought a thumb screw for the air mixture screw for the XR650L that I take to high altitudes every once in a while.... because when set to 4k ASL at 8K ASL it will not re start.... twist the air screw about 1/4 turn and it fires right up ! LOL
Ha, I appreciate your encouragement, Bob. Thanks for watching and sharing!
I am a newbie to tinkering with carbs on bikes. I really understood your explanation (with sound affects).
Thank you so much.
I’m going to need to hear the sound a few more times before I know for sure😂 Good job great explanations!
first video out of hundreds that helped me get this
Damn good information and the perfect amount of humility. Good teacher .
Explained well. A lot I already knew, but good refreshers
so well explained and the sound effects really helps :)
Awesome video, thanx man 🤘🏻
All 9 signs on too rich fuel were spot on. Now i know where to start.
carburators are still a learning experience for me and this video helped me allot !
Glad it helped - thanks for watching!
The sound effects are spot on bro 😂
I'm noticing a slight sputter once I reach crazing speed during the summer heat. Give it gas and intakes off, lean the jets some and get rapid backfire.. carbs..
Excellent presentation! Thank you!
Hello Greetings from Argentina, I have a 2-stroke motorcycle with a racing exhaust and I have a problem with the carburetor configuration. I can't find the right one. The spark plug has a reasonably good color and there are no air intakes. The motorcycle feels rich at 1/4-1/2 throttle, I tried touching the needle but it only works well, very hot. I have a question, I tried to progressively accelerate the bike in idle and it revs correctly up to half throttle, where suddenly it accelerates to the maximum. Is this normal?
My bike is feelings like its not even hitting the rev limiter the rpm fluctuate just slightly befor the limiter and causes crackling and poping when i over rev it, its not touching the rev limiter . Can you please help with the reason i am unable to understand...its just 2 months old bike.... this problem came when i got half lower engine case changed (connected to engine oil filter ) the engine sound is also more bassy and burping like sound... the rpm is stable at idle and not having any problem in reving but problem comes at higher rpm only
Loving the sound effects ur spot on !!!!!!!!
lol, thanks!
Video is very informative. But best part is sound effects. Love it 😊😁💫
what about the same elevation but different air temperature outside, like when the bike runs good in warm weather but worse in cold, is that even a thing? assuming that engines are heated up to spec
Great question, and yes that certainly makes a difference in jetting! Engines tend to run leaner when it's colder, so richening it a little should help.
@@MotocrossHideout ohh, I do have a lean mix it seems, thanks!
Yep, you're welcome! What is the first thing you're going to do now? 😀
@@MotocrossHideout 😂, I rather just give it to the mechanic, where he can tune it nicely 🤙
Gotcha, what's holding you back from tuning it yourself, if you don't mind me asking?
Also, do you know what your mechanic typically charges for that kind of work?
My 50cc two stroke is happy when I give it full gas and has good throttle response but when I give it like a quarter or half of the throttle it really ''stutters'' so it like rititittititi bogghh, but when I open the throttle more it's running nice. When I close the throttle at high rpm's or after accelerating it takes a while to go to idle rpm's so its not getting fuel or oil so I think i'm destroying my engine. It is a steel cilinder that has ran for about 150 to 200 km's so It's quite new. Had a lot of trouble getting it to idle right without changing jets, had to turn down air screw like 2 full turns for it to not revv like crazy on cold startup. But now having a hard time getting it to idle just a little higher.
Anybody any idea's if it's running lean or rich? And what to do about it?
I have Hero Maestro edge scooty, when i was setting mileage, through carburettor mixture screw, my scooty spark plug looks like wet and little blackish,, i want to ask you It's a richer side or leaner side
I have a 2 stroke 73cc aluminium kit. and its smoking a lot on wot, but I cant understand why because it's lean. the spark is brown but more on the lean side. I was running 122 main jet, after that, I installed 115 and it was SUPER LEAN and it still made a cloud of blue smoke. Now I'm running a 118 main and its still smoking. I have tried everything, like taking of power jet, different oil, other gasoline, different air temperatures, spark plugs, different oil mixtures, changing needles, needle clips, different carb positions and a lot more.
Is it liquid or air-cooled? How is the throttle response and power when you hold it wide open? Does it rev out smoothly and clean with a 122 main?
It's liquid-cooled. At the moment I have a 24mm carb and it idles a lot better but still smoking on WOT but a lot less. It acts lean but still smoking. The headgasket is not leaking and the gearbox oil level is normal. And does not smell like gasoline
?
This video was great but I’m still conflicted because my dirt bike has signs of both lean and rich symptoms. 😂
Ha, well start with the fuel/air screw and do one thing at a time! Let us know how it goes :)
Check your needle and jets. Make sure you are running proper baseline for your elevation.
I've followed your guide, and much appreciated, it's quite addictive aiming for the sweet spot and have helped 2 friends get their pilot set up and running better.
For my own bike I have the carb dialled in as good as I can, mainly on feel, taking the bike out for a good run.
But I've gone up on main jet and it pulls so much better mid but now it seems not to rev out as much at top.
Maybe over thinking this, but can running too rich improve mid range at expense of top end, evrything I'm.rrading is saying rich improves top end.
Thanks for sharing Scott - I'm glad you found my guide helpful!
That's a good question. From my experience, you shouldn't have to sacrifice top-end for midrange torque based on jetting. I like to lean out the main jet for top-end/peak HP until it starts losing power or bogs and then go back up (richer) 1 or 2 sizes.
the audio sounds were perfect explanation
Is it too lean when it pops and crackles when you back off the throttle eg going downhill at higher rpm??
Yes. A little bit of popping is okay, but a lot of loud popping and banging is excessively lean. Trying richening the fuel screw and see what happens.
I have a 2003 Honda xr70r I’ve tried to adjust the idle but the bike wont idle without me hitting the gas so if I let off the gas at a high rpm and it gets into the low rpm it shuts off and doesn’t idle does anyone know how to fix this?
Mine had problems giving throttle, turned out the oil pump had stopped working, so I am mixing oil directly in the fuel now.
Hey I know im a bit late but just wondering why the bike will hit the limiter if to rich becasue my 85 does that. Should i go smaller on the main jet?
I have a Ktm 85sx with a smart carb. It takes multiple kicks cold, takes a while to warm up, it bogs low in rpms and when I rev it a quarter throttle after it warms up I need to kill it because it wont drop down to idle quickly. But Im just not sure if this is an air leak or if its running rich or lean
It's definitely running lean (too much air).
However, it's hard to know without more info if it's lean from jetting or an air leak. I would try tuning the low speed circuit first (not sure what the smart carb has in place of an air screw).
Hi, What it could be if my bike randomly lost power and shots down. At that moment cant start bike, but after 3-5 min it starts ok. When bike goes in neitral gear, Power comes biger and biger and biger... like slowelly increasing rpms by itself.
Hmm, sounds like a possible electrical problem if it gets worse when hot? Perhaps a broken or loose wire somewhere. Increasing RPM also sounds like a possible air leak. Make sure the carb clamps are snug and the intake/air boot don't have any cracks.
Yes on point. Sounds make me learn easier
Without the sound effects I’d be lost ! ❤
Thanks, but there's no fuel screw to richen mixture on this carb. The only ways are to change jets or just raise the needle on the slider one notch.
hello i got a question my rmz 250 runs good but when i ride at like half thorrtle its like hitting the rev limiter but if i keep giving it more thorottle it goes away any idea if its running to rich or lean?
Sounds to me like it's rich. Could be float level too high, needle clip position, or dirty air filter.
I’m trying to fix a 2003 XR 70R that hasn’t run in about 12 years and the bike is struggling. I’ve put a new carb in it and the bike starts however the idle is often way too high, sometimes even idles at max rpms. Other times the bike will idle much lower and closer to where you would like it to idle at, however when this happens it will start idling quite high randomly and go back down after a bit. There is also sometimes where the bike will smoke a lot, often when the idle is really high. I can’t warm it up because the idle is way too high for a cold start and the adjustment screws don’t seem to change anything with the idle. Does anyone how I can go about fixing this
I’ve got a 4 stroke that I would say is running a little rich. But my biggest issue is flame outs or stalls. I’ve only ever rode 2 strokes and I’m wondering how to fix it
Bike is a ssr300 the stock carb was junk so I put a lectron on it and it improved it 100% but I still have the flame outs thanks for the help
Hey Justin, flame outs are often caused by lean pilot circuit jetting or a light flywheel weight.
Can't remember if the lectron has a fuel screw, but I would richen that and see if it helps (always test when the engine is fully warmed up).
@@MotocrossHideout I would adjust it but it has some of the signs of running rich like fuel smoke while idling and giving it gas but I’ll do some adjusting on it and see what happens thanks for the help
think i have watched this video at least 20 times already so helpful! wish i could remember half of it 🤦♂
Can we get a 2smoke special after the trail vids
Ha, thanks for watching! What would you like to see about 2 strokes?
@@MotocrossHideout Just how to tune one, as there a bit different than the 4t
The sound effects were on point 😂
1980 PE 175 2 stroke. When starting it takes 6 -8 kicks with choke on. When it starts it will rev high for many seconds. It is like my kicks are filling up the the engine with fuel then it starts. When I stop the bike I will turn off the gas and run the fuel bowl empty. I am familiar with jetting and the float level has been set. Any thoughts?
Revving high right away is typically a lean symptom. Either not enough fuel or there's an air leak around the carb/intake. Check for loose clamps or cracked manifold, then move to jetting. Let us know what you find.
I have a question what if i do fulll throttle and it bogs then dies i also tried to adjust idle screw multiple times
Main jet too small
I have both symptoms… i can start without choke easy but when i accelerate then it boha down and after bog its have power asf … i have beta rr 450 2006
Hmm, sounds like the fuel screw might need to be leaned out, and then the accelerator pump might not be working properly.
Hiya I've got a crf 250 when I pull a way it is making a funny scrapping noise but when I pulled the clutch in it stopped ,,can you please help me
Hard to know without more info. The the chain and sprockets straight and in good condition with proper tension?
If everything external is good on the bike, then I might want to pop the clutch cover off to make sure nothing is loose or broken.
Let us know what you find!
I have a crf150r that idle hangs when hot but also won’t kickstart when hot I don’t know what to do I don’t have very much experience
Could be an air leak or valves need to be adjusted.
just picked up a yz250, any recommendations on what ratio to use? It's not a stock bike, has race modifications done. I've never had to mix gas and oil before so pretty nervous 😅
How are you going to be riding it and what oil will you be using?
What should I do about it hesitating at half throttle, it’s really which I can tell but I’m not sure if I should adjust the needle or main jet
What have you tried so far? Is this a new problem?
@ yeah after my top end rebuild I started to notice, I’m on 2 stroke by the way, almost acts like the power just blanks out and it smoke a ton
@ I’ve leaned the needle but nothing has changed
@@Yz125-z4l Interesting. If it smokes a lot more after a top-end rebuild, that would make me think that something in the top end isn't right, such as the piston ring not sealing.
I know that's not what you want to hear, but it's not the first time I've heard of "rebuild" problems. I would probably do a compression test to see what it's at.
Let us know what you find.
@ came back at 179, I’m on a yz125
I like your examples 😂. If you have a video for selecting main & slow jets to solve rich or leen I would watch. Thanks for sharing
Thanks! Here's a video on knowing if your pilot jet is rich or lean: ua-cam.com/video/dzFzWIZsuDg/v-deo.html
I have an 86 Yamaha Jog that has always been tough to tune (too lean). Think I'll check for new air leaks. Thanks ✌️
I’ve got a bike that runs fine down low but full throttle high load it has no power and doesn’t accelerate. Ive cleaned the filter changed to new plugs and cleaned the carb,( I may need to clean the carb again). This bike has ran great all summer so I’m not sure what’s going wrong now. The bike usually has crisp throttle response off idle but some times on snappy throttle twists it stumbles at first.
Hey Evan, does it happen more on hotter/high humidity days? It sounds like it might be running rich (if it's sputtering), which is typical on hotter days. If the compression is good, you might need to go smaller on the main jet (if it sputters at WOT).
Let us know what you find out, as well as the bike you're tuning :)
Thanks for the awesome information.
You're welcome, thanks for watching, Dale!
What if ur bike starts first kick no matter the temp
Mine is bogging while sudden accelerating like you have said. But when i check the sparkplug the of it is black. Hope this will have answer. Thank you
Yeah, that's why spark plug reading isn't always accurate. Does it bog when you turn the throttle wide open? That could be lean on the main jet, while the black plug is caused by rich on the pilot jet.
@@MotocrossHideout it is bogging when i turn the at full throttle. The bike is not moving the engine is like its going turn off. But when i am on drive. Just like your example on number 6(bog while accelerating)
Yeah that sounds to me like a lean main jet (too small). I'd go one or two sizes bigger and see what it does.
Not sure what bike it is, but some bikes also don't respond as well when you "whack" the throttle open, especially if it has an older carb without an accelerator pump.
@@MotocrossHideout ok i try changing my jets into bigger one. I am currently using 125cc motorcycle with a 28mm carb jettings are 100 and 38.thank you
my 4 stroke especially in first gear likes to jump like cut in n out when i get on the gas and when i hold it like half throttle it just sounds horrible
Sounds like it needs some tuning - what have you tried so far?
Does this apply to fuel injected engines?
Hey, i have a little problem with my 6mth bike, starts hard on choke and dies when warm dies when rapid gas, lowered gas amount still same problem
Not sure what bike that is but have you tried adjusting the air/fuel screw or the idle screw?
I have a yz 85 bored to 105cc used the same jets and was fine,then I installed vforce4 reeds and rebuilt the carb with the same size jets but new ones, now the bike doesn’t want to start from cold with or without the choke without giving some throttle, even when engine is warm it won’t start without throttle and when I give it some revs and let off,the engine wants to cut out, also turning the idle screw doesn’t seem to change the revs, and has a minor bog from 0-1/4 throttle but once hitting the bands it runs fine, any idea what this could be?
Sounds like it might be rich on the pilot jet circuit. Have you tried leaning out the air screw? I recommend grabbing my free tuning guide :)
@@MotocrossHideoutyes the air screw didn’t seem to make a difference so I’m going to try a smaller pilot jet and see if it’s better or worse thank you, I wasn’t sure if it’s too lean or rich
@@MotocrossHideoutI’m using 45 pilot and 138 currently which are stock with yz 85
i will have it in neutral and rev it for a bit but i go wide open throttle n sometimes itll bog for a second
It could be a little lean on the main jet. Hard to know for sure without more info/sound.
Bike doesnt need choke to electric start and fires within the first 2 cranks. Bogs hard when i pin the throttle but i can roll in and have good throttle response. I dont get any sputter or hanging idle. It gives me lean and rich symptoms
Hard to diagnose without more info. What bike? Is engine fully warmed up? What throttle position does each symptom happen? Has it always done this or has it gotten worse?
@MotocrossHideout yamaha ttr-230. Moved the bike from sea level to about 7000. Jetted Down from a 117 to a 106. If I pull the scree almost all the way out it runs better with a huge bog on initial throttle but will pick up. Today I moved up to a 110 and was able to put the screw in about half way. Still a bog in the start with both engine cold and hot. I've been chasing it for about a year now
Okay, first you need to get the fuel screw properly tuned. The fuel screw is on the bottom of the carb in front of the float bowl. It controls 0-1/4 throttle position. That will tell you if the pilot jet is too big, small, or just right.
Then the main jet controls roughly 3/4 to wide open throttle position.
Always make one change at a time and only when the engine is fully warmed up.
@@jaredradison8372 Okay, always make one change at a time. Get the fuel screw/pilot sorted first - that's from idle to 1/4 turn throttle position.
If it's bogging (engine dying) at WOT, the main jet is probably too lean/small still.
Don't make changes if the engine is cold/not fully warmed up.
my bike is muttering when i get in 5th and run it wide open what do i do to fix it?
Hey Gage, what exactly do you mean "muttering". What does it sound/feel like?
hey guys, i need help, i was riding completely fine and when i stopped it stalled. I kickstarted it and it was stalling when i didnt put a lil bit of throttle. So i quickly went home and when i was dricing home i figured out that my gas is bad. When I held the throttle for a while and then let it go, it held on for a while. When I just moved the throttle, the throttle stayed for another 0.3 seconds, which didn't happen before.
Spot on sounds mate
That was awesome buddy very helpful thanks
Glad it helped :)
Quick question:
So if my bike needs the idle adjustment screwed in ALL the way, that means the carbs need adjustment?
That's definitely one symptom. That usually means it's running rich, which could just be the jetting, but it could be a very dirty air filter or perhaps a worn out engine that's running low on compression.
@@MotocrossHideout would it feeling like it's "chugging" on idle in 1st gear tie in with it being "too rich"?
Im praying it's not a worn engine, I made sure the carb and air filtration system was perfect before I put the carb back in.
It's a 96' vulcan750, and I got it with the carb detatched because my dude rebuilt it but couldnt figure out how to put it back in
@@rdowg It's hard to know for sure without seeing/hearing it.
To me, "chugging" would be riding at too low of an RPM and the engine is about to stall.
@@MotocrossHideout Crap, oh well 🤷♂️
Now that I think of it, I should probably re-tune that carb before I start asking about idle on 1st feeling like it's got too low rpm
Thanks for the replies!
Mine does the ritch thing under half throttle and the lean thing over half throttle idk what to do, i cant even drive it over half throttlw it just dies and it sputters under half pls send help🥲
I have a klx140 with bore up kit 66mm, cam lift, exhaust. it runs great at 3/4 to full throttle but in technical slow section specially rocky section its like its coughing/sputtering i'm using 28mm carb with 38/120 jet 1st clip on neddle. is the pilot jet too rich? it gets worsen if I pull the choke from 0-1/4 throttle.,by the way usually running at 200-800 ft.
That sounds rich to me. Not sure which 28mm carb you're using, but have you tried leaning out the air/fuel screw? Grab my free guide to learn how to do it in just a few minutes to know if your pilot jet is too big.
There is a map that shows the overlap of different systems in the carb. Find that and specifically dial in the area that’s affected. I found out when you understand the concept of the systems they each have to work well for that smooth linear operation ir you get what you have. Sounds rich too. Could be needle size and placement as well as air fuel. Is screw before body of carb is adjusts fuel is after main body (float bowl) and it’s closer to cylinder head it adjusts air. Look for that breaks it all down. I think it the RD jet kids or??
I need the running lean ring tone for my phone ;)
Thanks, it seems like my bike is too rich in mid range and ok on near cut off
My quad (250 4 stroke) struggles at low rpm and high load, and it really picks up power above like 4k rpm
Does it sound/feel lean or rich based on this video?
Hey mate I just did an oil change on my 125 pit bike and now it overheats I’m not sure why
Is the oil level set correctly? Did it have this problem before?
If the oil is good then there's probably something else going on.
@ basically I bought this off Facebook
It was idling good but the oil was very dirty so I changed it and added 700ml 10w-40 semi synthetic oil and now the exaughst gets very hot right after starting it
@@aayantheangler7101 Exhausts normally get very hot. If it's glowing red, it's because it's sitting too long or the pilot jet/mixture screw is too lean, typically.
@@MotocrossHideout oh okay thankyou very much
Great video! Sounds effect very helpful!
Great vidoe man but i still can't figure out whats wrong with mine.
I have a Crf250X, it starts like it should. When i give it some throttle the rpm stays high and wont settle to normal. When i pull the choke out and back in it goes down to normal. But again when i throttle it stays high. When im in gear i can let the rmp go down by pulling up with only the clutch.
If the bike stalls of I want to start it when it's warm, it won't start and eventually drags the battery empty.
I played with the air mixture screw and stationary idle screw but I can't figure it out 😬Maybe I did something wrong.
Could there also be something wrong with the throttle body you think, like scratches or false air?
That sounds like a hanging idle, which is a lean condition, usually caused by the fuel screw/pilot jet being too lean or an air leak. Make sure the carb clamps are tight, there's no cracks in the intake/air boot, and that the fuel screw has the proper o-ring/washer on it so no air is leaking by.
If it's always done this, then I'm guessing you just need to richen it up. If it's a new problem, the pilot jet might be dirty and need to be cleaned or replaced - assuming there are no air leaks.
Let us know what you find, Wesley!
I signed up trying to get the tuning tips and didn’t receive it. Got an email about trail riding.
You should have received it within a few minutes of signing up. Check your spam folder in case it went there.
If it's not there, just reply to one of my emails and I'll personally send you the guide.
-Kelley
What is the difference between a lean bog and a rich hesitation?
ua-cam.com/video/U9zztj186h4/v-deo.html
Hey, got a strange problem i can tune the jets up or down even to where its perfect and the plugs golden, yet when going over 80ks so 4th gear and up it will cut out after a few seconds of throttle its a old bike ts250 but any help would be appreciated, thanks!
Does that bike have a tachometer to see the RPM? Are you hitting redline? If not, it might be running too rich on the main jet.
@@MotocrossHideout Thanks mate and no tacho on mine atm but its probably rich yet when i downsize the main it cuts outs as well, but i know its not redlining cause it used to work fine, so a bit stumped
Other things can also make it run rich, such as a dirty air filter/rag in airbox, or a worn engine.
@@MotocrossHideoutYeah even changed the filter, might just be on her way out then
Thanks for the help but much appreciated! @@MotocrossHideout
Clutch control is related to engine temperature?
Poor clutch control (slipping it more) will creat more friction and heat, causing the engine temperature to increase. Does that make sense, Angela?
@@MotocrossHideout Oh yes it makes a lot of sense. But my question is if it results in the engine overheating because of the increased friction of the clutch? I mean I thought the clutch was located more near the tires and not the engine. If that is correct, then how the clutch would produce more heat for the engine?
@@angelamartim8337 On a dirt bike, the clutch is inside of the engine (crankcase).
@@MotocrossHideout Okay, got it now thanks!
Hey mate any idea why my 250exc 2008 has no top end power tops out about 85kph and its running 50mm of oil to 1 litre of fuel cheers
What does it sound like doing that? Have you tried to change anything yet?
@@MotocrossHideout just the plug was crusty as thinking if just going back to oem jetting and mixture see what happens
@@MotocrossHideout runs sweet through all the gears good intill 5th then it's bogs like crazy stock sprockets to
Crusty as in the spark plug is black? I would try going down on the main jet and see what happens. Don't change the oil mixture - just do one thing at a time so that you know what made the difference.
@@MotocrossHideout yeah just going to take it to the local mechanic get him to have a look at it got no time
My 4 stroke 250cc quad does frive alright has alot of power but when decelerating i hear alot of pops from the exhaust,i thought that might be becouse of a to rich mixture but i have no problems or signs whatsoever
A little bit of popping/crackling is fine, but excessive/loud popping generally means the fuel screw/pilot jet is too lean.
Sound effects AMAZING
Sound effects definitely do help😂
What grade of gas should be run through a crf150rb? Is it ok to run premium gas through it? That's all I put in my lawn equipment and vehicles.
Yes, if your 150R is stock, 91-93 premium is fine to use.
use non erhanol if available😊
Yep, ethanol is not good in any machine (especially a carburetor) if you want it to last more than a few weeks.
@MotocrossHideout gotcha! Thank you for all that you do! I have so much more confidence and a much better rider in just a week's time by watching and paying attention to all your lessons and advice. I don't want to find myself overly confident and always maintain a respect for the machine. I am so in love with my bike! I'm going to always be good to her, and she'll always be good to me.
So I kind of have symptoms of both. Easy start. Bogs and dies with throttle. Hanging idle. Poor throttle response.
What should I be looking at next? It’s a 90cc 2 stroke atv.
Kids were riding fine one day and just started acting up, hasn’t been the same since.
Carb rebuilt, new jets and all. Also has new oil pump.
Sounds like it might be lean. Have you tried adjusting the air screw? Also, make sure the carb clamps are on and tight so there's no air leaks.
@@MotocrossHideout so far I haven’t found any air leaks. Seems to idle best with air screw around 1 turn out but still bogs out with throttle. Any idea what could cause it mid-ride?
What throttle position is it at when it bogs? 1/8, 1/4, 1/2, or full?
@@MotocrossHideout so, its mostly 0-1/4, almost immediately. when I can get it to rev, I can tell its cant go full throttle. top end rebuild kits are fairly inexpensive on these, could that solve it?
Okay, I'd try going one size larger on the pilot jet and then re-adjust the air screw for best throttle response and see what happens.
Mate I need some help, my bike starts just fine with one kick in lower elevation, but in higher elevation it can't do that anymore, It's hard to start, when I check the plugs, the color of it is grayish (I checked it in lower elevation), what seems to be the problem here mate? It seems that the RPM runs too low in higher elevation that's why It doesn't start easily, but if I bring it up, the idle in lower elevation would be too high
Good question - that's a very common problem with carbureted bikes when changing elevation. When you go higher, the air is less dense and it will make your bike run richer, so you'll need to lean the jetting out at a higher elevation, and then richen it back at lower elevation. Start with the air/fuel screw. Does that make sense?
What’s your recommendation when you have symptoms for both rich and lean?
My bike is getting super hot in a very short amount of time (before actually riding). It starts really easy when cold with or without choke and revs really high until bike warms up and then the revs die down and even out. I’ve just rebuilt the top end after the motor got that hot the piston seized the inside of the barrel. After about 10 minutes of riding.
Sounds like you are rich on pilot jet and lean on main jet
I have a DR350SE with a tm33 pumper carb. At idle, it has a bog when quickly snapping the throttle, and I can't figure it out. I've tried changing jets and would always end up too rich, and I've checked the pumper needle multiple times.I even went as far as installing a wideband O2 sensor in the exhaust. The tm33 pumper carbs don't have adjustments on the pumper, it's just a rod. The bike runs great other than that, I've been trail riding with it for a year. If anyone has any ideas, I'd be willing to try them. 😊
What throttle position when you quickly open it? If it's wide open, then I would try adjusting the main jet size to see if it helps.
@@MotocrossHideout It's when the throttle is closed and I quickly open to wide open it will bog. Which is lean, I think. I've gone up a main jet and it spits and sputters at 3/4 - full throttle and the wideband gauge is pegged in the 10s full rich. So I changed it back. I've heard it's hard to dial these pumper carbs in on a dr350.
If it's a 4stroke and blows white smoke it's a problem with oil in the combustion . Not good. Engine worn out. Brown or black smoke is unburned fuel. A mixture problem .
Hey my bike backfires and shoots a flame about every 7 seconds when i accelerate, its fine and feels good untill about 60% throttle then it starts to happen. It also bogs at super low rpm if i just rip the throttle. Any tips/ideas ?
What have you tried so far? I recommend grabbing my free fuel screw tuning guide and starting there if you haven't yet ;)
Can some one please help me if i gou past 3/4 of throttle my bike starts surging the whole time it is a 4stroke carberator engine what can be the problem
Sounds like it's too lean on the main jet (not getting enough fuel), or possibly a weak fuel pump if it has one.
@@MotocrossHideoutcan a incorrect float level also cause the engine to surge
@@bofflombard8755 Yep, float level will affect all jetting, thanks for sharing, Boff.
@@MotocrossHideout I found the problem I lost spark on the coil and spark plug wire and I adjusted the float level it is now revving out after I bought new parts
@@bofflombard8755 Glad you got it figured out - thanks for letting us know!
really helpful, thx bro.
Glad it helped - thanks for watching.
Excillent explanation
Glad you think so!
Needed this, thanx dude!
Happy to help!
What’s a symptom of 250f feeling slow in top gear? Was riding with my buddy who has a 450 and felt like I was topping out at like 50mph. Possibly the sprockets? It is a used bike. Seems to have plenty of power was just suprised thought the top speed would be more
It has a power commander. After watching more of your video that is a better explanation it seems like it also gets rev limiter fast! In 5th gear
What bike? What gearing/sprockets does it have?
@@MotocrossHideout I’ll have to count the teeth, some are broken off need new ones. It’s an rmz250
@huntnfishin2074 teeth broken?? Get new sprockets and a chain and then see what happens.
My yz85 fouls plugs every ride I have an fmf shorty on it with I think rich jetting from the guy I got it from and I ordered stock and a size down for each Jett. Does that seem reasonable?
Yeah, stock is a good starting point, but they often tune the race bikes a little on the rich side from the factory. Start with the air screw - grab my Free guide if you haven't already;)