Thanks for you video,I have an 08 klx450r and found it had no squirt at all,changed jets and now accerarator pump diaphragm. I was definitely lean before main was 147 now 170 + need needle will know very soon it I fixed it. But was curious were you got the graffics as I am looking. Thanks again James
+kayoss559 You know what else is crazy? You buy a 3-6k dirt bike and won't spend $10 to learn how to jet it properly? Feel free to take it to a dealer and pay 150-300 to have it jetted. Good luck. If you want help, feel free to ask questions, those I answer for free.
Hey, I recently purchased a dual sport (23 xr150) and it comes out of the box very lean, I’ve been watching your videos and I’ve found them very helpful however I’m kind of trying to figure out if I should go up or down a pilot size (stock main 105) (stock pilot 35) as it runs too lean, at least I think because when I got to give it a sudden punch of throttle, it bogs and turns off. I’d like to note that the needle jet is non adjustable (no clip) and the float is all plastic, non adjustable. There’s also no air/fuel mixture screw. I’m not exactly sure if I should go up or down on the pilot as I get confused on this matter in particular for the idle/pilot jet. Where I live is less than 1000ft elevation and I have gone up in main jet and I’ve gotten more power just still bogging when I give it throttle. Anything helps thanks
Hello,, on my '05 WR450 it runs perfect but pops alot on decel and airscrew is 3 turns out, not going anymore, any recommendations? Should I go up on the pilot size 1 or 2 ? TY
On my 2005 KTM 250sxf, it bogs when I wack the throttle from the bottom and and shoots fire and pops. I bought it used and it came with an fmf exhaust system. I checked the recommended jets from fmf and My main and pilot jets were both off by about 2. Don't remember whether it was 2 up or down. But off. What should I do? It starts 1st kick cold and 75% of the time it'll start 1st kick hot WITH the hot start. Please help! By the way, GREAT video!
JakeWardell 19 Bogging during throttle whack is the accelerator pump circuit. You may not even have a leak jet to change out on your model. Read this and let me know if you have a leak jet: www.howtomotorcyclerepair.com/jeta4stroke/ Matt
Man i need help. I have 03 crf450r wont run off choke an its hard to crank. I clean the carb an everything everything is clean. What jetting u recommend an the mixture screw ? I have a 175 main idk if others are stock or not i have a MRD pro comp exhaust on it
I've installed a full exhaust kit, K&N intake air filter, and a jetting kit on my Atv and it shoots flames when I let off throttle, like very small backfires but I don't even know if you would call it a backfire cuz they aren't very violent, but my question is, is it supposed to throw flames or do I need to adjust one of my jets? If so, which jet or pin do I adjust, and wich way and how much should I adjust? I'm just trying to better understand how my engine works, and help is greatly appreciated thanks.
MatthewMCRepair MatthewMCRepair It's a 2007 Polaris Outlaw IRS 525cc, also I am using the exhaust without a spark arrestor, but I thought that it would only spit fire when I gun it rather than when I let off throttle, that's why I'm wondering if I should adjust the jets or not, but it doesn't bog out at all, other than the very small backfires the throttle is very smooth and snappy. And it currently has a JD jetting kit, I went from the stock 148 main jet to a 160 main jet, used the red tipped needle with 5th increment or clip down on the needle, and I didn't adjust the pilot jet at all.
sir i have a new carb on my scooter..my question is does the pilot jet affects the motorcycle when it is running already? or does it only functions during starting and idling your motorcycle?
+MatthewMCRepair thanks sir..need an advice(160cc scoot)..from 24mm carb i am using keihin pe 28mm now..mj 125 and pj 42..when i twst the throttle its like it the engine would stop a little..i dont know the word to describe it..does this mean i will lower my pj..
MatthewMCRepair Hi Mathew. I have just put bigger jets and lifted the needle in my 2014 wr250f. She idles well and generally runs well providing I roll on the throttle slowly. If when riding I accelerate quickly she splutters then fly's away! Can you give me a tip? I have also removed the snorkel. Cheers john in UK
Anyone know what i have to change on my 26mm molkt on a lifan 125 to get rid of bogging? I have tried from 100 to 122 main jets (102 is the stock one) and nothing is helping, i have also tried 10 sizes bigger pilot jet, im not sure if it helped, but maybe it did a little. I tried a cloth around the air cleaner that removed the bog but it doesnt work well with it on. So do I have to get bigger or smaller main jets and/or pilot jets? I appreciate if someone could help
The bike in the video has the original muffler packing that probably needs to be replaced. Also, the fuel screw was set at 2-2.5 turns out, so it probably should have a larger (maybe). Keep in mind that some popping is normal with a "race" engine and "open" pipe. Do not try and jet this popping out.
@MatthewMCRepair. My 2008 kx250f is backfiring/Popping alot on deceleration. Iv changed the spark plug and the valves clearances are fine. Do you think a different jetting configuration would do the job. If so any advice on the configuration. Thanks
On decel it is usually a lean condition. Make sure there are no vacuum leaks, exhaust leaks, carb is clean. Tune your fuel screw, I have a video on that. howtomotorcyclerepair.com/how-to-4-stroke-mx-fuel-screw-adjustment-yzf-crf-kxf-rmz-fcr/
Matthew what would you suggest for me to highten my YZ250F rear shock, I have had it totally dissmantled and no matter how hard i try it wont turn, I used a spring compressor 2 actually to take the pressure off the spring while trying to turn the bottom spacer and sprayed the hell out of it with WD40 and it still wouldnt turn, I am 16st 7lb and it feels like i'm riding on the floor when riding this YZF250 lol
do you need and air/fuel screw for your carb? I have a yz250f09 and i just noticed my carb doesnt have it but it still runs ok and starts with one kick?
@@HTMR oh thank you sir! i will definitely check my carb when I can. Good content as always sir. May i suggest that you make a video about fixing intake boots i dont see a lot of videos about that.
On a 03 KTM 450 after complete top end rebuild , cylinder re sleeve, new piston & new titanium valves and new adjustable accelerator pump with every thing tuned and running perfect. one day after a few months my muffler started melting my side plastic muffler cover, then a few days later the bike starts to lose power at higher RPM. Any ideas ? Thanks for any help on this. Carb is KEIHIN FCR-MX 39 Carb jets stock 170-40, in shop book 175-48 Jets In as of 03-22 - 178/50
Hey bud, I just bought a 08 crf150r and it has some carb issues. Starts and runs on choke, revs and everything, once choke is completely off it bogs, sputters and dies... any ideas? just went through and cleaned the jets and did a basic clean.
+MatthewMCRepair did a pretty damn good job of cleaning out the main pilot and starter jet, got a thin piece of wire from a brush and cleaned them out and sprayed through them, took apart the accelerator pump and cleaned the junk out of their, started playing with the pilot screw and turning it in half turn every time, def likes to backfire and pop turning it in. works better then before but doesn't seem to be squirting fuel out from the accelerator pump nozzle, snapping the throttle it def starves.. just seen water pissing from the weep hole and upon inspection the shaft is grooved and pitted so I'm going to need a new water pump and seals.. till I get them in I won't know how it runs
+MatthewMCRepair just took the car apart again and split it in half and found the acc nozzle squirter, it looks like a jet that you can unscrew but it's actually just a press fit.. (luckily it went back in no problem) of course it was clogged and after 10 minutes with a piece of wire I managed to clean it out. it Works! like I said though, i can't start it as I have the right case halve off and leaking water pump out... ended up stripping the impeller (left hand thread :( and it's aluminum) takes a week to ship :( water pump shaft has some pretty good wear marks and putting were it wore down.. $150 and I got me a new water pump assembly comin... will let u know how she runs on Wednesday
Joe, what year make model do you own? The service manual has a procedure for this. It usually involves placing a pin under slide and then adjusting the screw. I'd have to review it myself, it's been a while since I looked at it.
Joe Jones Joe, go to my site and type in "kx250f" in search box. I have the free service manual for an 06' and it should be the same procedure for your 07'.
Hi theoretically they say at idle when you push hot start you should i nice strong rev to have your pilot jet and fuel screw correct. I have wr 450 2004 with 48 pilot(stock45) and about 2 turns fuel screw, when i push hot start on idle it slightly revs like a bog or something, what shall i do with my pilot jet or any other jets? If i seat the fuel screw all the way in it will eventually die (doesnt this mean the pilot is also right)? The bike starts and drives fine but how to i get it perfectly jetted?
I don't judge jetting based off how the hot start acts. The hot start should introduce more air, leaning it out, and make the RPM's go up though. Watch this video on proper fuel screw tuning: ua-cam.com/video/kUw41sUQbTY/v-deo.html
So that means im set pretty good with pilot and fuel screw even though the hot start acts like that? Will a needle or main have any effect or shall i just leave it the way it is?
my 2012 yz250f sputters cmming out of corners and when i hit the gas and wack the throttle it sputters as well, the wide open position int great either help!!
Hi Matt,I have a 2010 KX250F with an Athena 290 Big Bore Kit, I got a carb kit from Tokyomods for a big bore, they gave me, 68 leak jet, 45 pilot jet, 178 main jet, NCYU needle, 4th groove down, Fuel screw 2 turns out, I can't get it to start, Please help!
Have you tried different fuel screw positions? 1.5 or 2.5? Also try no choke and pull hot start. They are a pain to start until the fuel screw is tuned.
I have an 07 kx250f and I'm running 175 main 42 pilot not sure what the leak jet is. Do you have any recommendations for all 3 jets that will improve all around accelleration and fix bog ?
Love the vid. Was wondering would this also apply to the 05 with the steel frame. I dont think they changed much in the engine but just thought i would ask
I am new to this. Thanks for your video. Is all of this jetting related to elevation? I live at 5500 feet, but want to ride in Glamis at an elevation of 335 feet. Would I need to have two jet kits for each of my elevations?
hello i just installed a hot cams stage 2 and a jebco exhaust . bike has not bin jetted yea but it starts and runs good. should i go up on my jetting ?
I have some questions about my 05 rmz 250. The throttle hangs for 1-2 seconds before going down in rps after I rev it and the idle has to be set REALLY HIGH otherwise it´ll die. Do you think I need a bigger or smaller pilot jet? Or isn´t it even the pilot jet I need to change?
I have some videos on my channel where you can here/see what i mean but I just did a top end rebuild so I can post a new video if you want to see how it runs after the top end rebuild. Thanks
well i noticed when you showed the bike running when you were shifting you were not using the clutch you were just ahofting without the clutch witch thats what a quick shifter does wasnt sure if you added one
So my power is bogged from quarter throttle to half throttle. Low and top end are perfect, will changing my main jet reduce this? It is it the needle ? I got a little confused haha.
That is all related to the accelerator pump not squirting enough fuel. Click on blog post under vid description, it goes over how the system works and how to fix it.
would this jetting work at 3300 ft above sea level ps my bike is an 04 yz250f with an fmf power bomb header and an fmf factory 4 exhaust currently running 178 main 42 pilot 90 leak jet stock needle middle clip currently running fuel screw at 3 turns out to make the bog a little better
MatthewMCRepair ok it runs pretty good acept for the bog is really bad and it starts kind of hard when it's cold but when it's warmed up starts first kick
Hi, i have a crf250r 05 wich bogs really much and has a hard time starting cold. Its too lean mixture, called honda dealer he said go 45 in leak jet and main jet i forgot its like 172 original or if you know what size i should buy please link them! I've got a pro circuit pipe on aswell so if that would make difference on the jetting
+breezeffs jump Here are PC's jetting recommendations for your bike: www.procircuit.com/jettingspecs2.htm I would plan on getting an adjustable fuel screw and a 45 pilot just in case. Also, a 45 leak would work good. If it still bogs, slap an oring on it. Visit PC's site for main and needle recommendation.
+MatthewMCRepair hello, thanks for the answer i checked out the site and it seems some jets are wrong written? Main:170 pilot:42 and leak 70? Should it be 70?
+MatthewMCRepair could you just tell me what jets i should buy? Gonna try leak jet and main jet and do the oring mod, it bogs so bad like in the video orher then that it never bogs..
MatthewMCRepair I have a question , I'm using a 175 main ,42 pilot I'm still using a 55 leak jet I'm clip 2 on needle bike runs fine when hot but on a cold start with choke it will start first time but if I try and take choke off after 5 mins it will try and die and run crap.but like I said once warmed up to running temp it's fine....my old crf I'd use choke just to fire then immediately take it off and it would rev up fine am I well off on my needle ?cheers Sam
Sam, you never mentioned year make and model. If you have your fuel screw and pilot jet sized correctly, then it should start cold/hot no problem and run fine everywhere in between. Watch this vid: ua-cam.com/video/kUw41sUQbTY/v-deo.html
MatthewMCRepair can you please help me, Ive got a 2009 crf250x with the CCC mods and a jd jet kit and it backfires just as much as that yz250f in the video and I have swapped out the pilot to a 45 and lowered the needle two slots. It performed horribly with both of them and there was still backfiring so I went back to 42 pilot and 2 up on the needle the way it was before. So what is causing the backfiring? is it normal for a 4 stroke to backfire that much? thankyou.
+KingBandz So you have a 2009 crf250x? What modifications? Location? Pilot jet size? Did you adjust fuel screw? Air leaks? Leak jet size? Answer these so I can better help you.
I have done the airbox mod, swaped the 250x exhaust for a 2005 crf250r can, and JD jet kit. I am in Erie, PA. The pilot is the stock 42. I have attempted to adjust the fuel screw but It starts to not pop at around 3 turns out but its about to fall out but when I put in a 45 pilot even with the fuel screw in all the way it performs wierd. I got it from my friend and everything other than the mods I stated are stock so I'm assuming the leak is stock. I havent looked at any air leaks on the header to pipe or pipe to exhaust yet.
+Foster Schutt Explain how it performs weird with the 45 pilot? Is it a genuine Keihin pilot jet? You need to check for air leaks on carb boot and exhaust.
with the 45 in it sputters on the bottom end, making it feel like a 125 2t powerband. I'm not positive if it is a Keihin pilot jet i will contact my shop tomorrow when they are open. I have checked the intake side of the bike from the filter to the carb for leaks, there are not any,
I have a 2004 Crf250r with a fmf powercore 4, I am at 4450 elevation. What jets would I run? Specifically leak jet. My bike falls on its face when I crack the throttle. Already tried o ring mod. Please help!
I'm at 700' and run 45 leak jets and oring mod. Since you are higher up, maybe a 50-55 would work good. Here is the link to leak jet: www.rockymountainatvmc.com/p/930/47202/Keihin-N424-52-Series-Leak-Jet?term=leak+jet Also make sure you tune the fuel screw and make sure the pilot is sized correctly, that helps with bog to some extent. Watch this: www.howtomotorcyclerepair.com/how-to-4-stroke-mx-fuel-screw-adjustment-yzf-crf-kxf-rmz-fcr/
+brayden runner not sure if it applies to dirt bikes but if it bogs you might wanna check the diaphragm in the carbs. I had a sport bike that would bog and I didn't know what was wrong till i checked. turned out it was a torn diaphragm
Pls someone help me !!!! I have a very hard time trying to start my yz250f .. When I do start it with the choke on after 10+ plus it idles so high !! When I take take the choke off it will take a lot for it to start and when it does it will bog out ... ??? Also it pops so much & back fires . How do I fix this problem bc the bike sounds like shit I need to fix ASAP . Btw it's my first bike .
bike runs awful the guy who had it before me had timing way out and a pipe that has no name and the yamaha dealer is a joke gave me wrong jets 2 times in a row so its worth the 15$ don't have much to lose
Nasty782 Bike currently runs awful? Don't expect the needle to cure this. I would get it running right and then experiment with jetting. Each needle/jet is stamped, so I would tear down carb and verify against stock.
I’ve got a 08 yz450f always have a problem when I first start it and let it warm up the first blip of the throttle it’s dies. When I start it up again it does not do it it’s always the first blip of throttle any suggestions? I want leaning toward accelerator pump?
Damn i love your videos!!!!
Thanks!
Ok
Ok @@HTMR
If you're gonna waste our time atleast say so at the beginning
Read the title, it says sample.
Squid WithGear fuck oath bullshit
Tru
Pop on decel and a lean pop in low rpm either the air mixture is out or too small of a pilot jet or tight valves or exhaust leak
Shouldn’t be backfiring in deceleration like that AFTER you Jett it man .
Lmao so true
He literally said if you were paying attention that he still needs to fine tune it lmao
your crazy no ones paying 10$ to watch this when its online for free.
Good luck jetting your carb. Let me know if you have any questions.
Thanks for you video,I have an 08 klx450r and found it had no squirt at all,changed jets and now accerarator pump diaphragm.
I was definitely lean before main was 147 now 170 + need needle will know very soon it I fixed it. But was curious were you got the graffics as I am looking.
Thanks again James
It's not the full video, because this guy wants a minimum of $10.00 to watch the full video, on his website. Crazy !!!!!
+kayoss559 You know what else is crazy? You buy a 3-6k dirt bike and won't spend $10 to learn how to jet it properly? Feel free to take it to a dealer and pay 150-300 to have it jetted. Good luck. If you want help, feel free to ask questions, those I answer for free.
True, but it does not cover everything.
Hey, I recently purchased a dual sport (23 xr150) and it comes out of the box very lean, I’ve been watching your videos and I’ve found them very helpful however I’m kind of trying to figure out if I should go up or down a pilot size (stock main 105) (stock pilot 35) as it runs too lean, at least I think because when I got to give it a sudden punch of throttle, it bogs and turns off. I’d like to note that the needle jet is non adjustable (no clip) and the float is all plastic, non adjustable. There’s also no air/fuel mixture screw. I’m not exactly sure if I should go up or down on the pilot as I get confused on this matter in particular for the idle/pilot jet. Where I live is less than 1000ft elevation and I have gone up in main jet and I’ve gotten more power just still bogging when I give it throttle. Anything helps thanks
Hello,, on my '05 WR450 it runs perfect but pops alot on decel and airscrew is 3 turns out, not going anymore, any recommendations? Should I go up on the pilot size 1 or 2 ? TY
I'd run at least one size larger pilot jet than stock.
Thanks for your videos...i like to ask you, i have a 08 yfz450 and wht suze on the jet i can us normely
Does the nfpr needle works with the Honda ?
On my 2005 KTM 250sxf, it bogs when I wack the throttle from the bottom and and shoots fire and pops. I bought it used and it came with an fmf exhaust system. I checked the recommended jets from fmf and My main and pilot jets were both off by about 2. Don't remember whether it was 2 up or down. But off. What should I do? It starts 1st kick cold and 75% of the time it'll start 1st kick hot WITH the hot start. Please help! By the way, GREAT video!
JakeWardell 19 Bogging during throttle whack is the accelerator pump circuit. You may not even have a leak jet to change out on your model.
Read this and let me know if you have a leak jet:
www.howtomotorcyclerepair.com/jeta4stroke/
Matt
Man i need help. I have 03 crf450r wont run off choke an its hard to crank. I clean the carb an everything everything is clean. What jetting u recommend an the mixture screw ? I have a 175 main idk if others are stock or not i have a MRD pro comp exhaust on it
Was wondering if the needle would work on my keihin on my kx250f,2009 tia
I've installed a full exhaust kit, K&N intake air filter, and a jetting kit on my Atv and it shoots flames when I let off throttle, like very small backfires but I don't even know if you would call it a backfire cuz they aren't very violent, but my question is, is it supposed to throw flames or do I need to adjust one of my jets? If so, which jet or pin do I adjust, and wich way and how much should I adjust? I'm just trying to better understand how my engine works, and help is greatly appreciated thanks.
What year make model do you have? Did you jet the pilot and adjust fuel screw?
MatthewMCRepair MatthewMCRepair
It's a 2007 Polaris Outlaw IRS 525cc, also I am using the exhaust without a spark arrestor, but I thought that it would only spit fire when I gun it rather than when I let off throttle, that's why I'm wondering if I should adjust the jets or not, but it doesn't bog out at all, other than the very small backfires the throttle is very smooth and snappy.
And it currently has a JD jetting kit, I went from the stock 148 main jet to a 160 main jet, used the red tipped needle with 5th increment or clip down on the needle, and I didn't adjust the pilot jet at all.
another good vid just bought the part 2 kx250f worth every penny
Cool thanks!
On a 4 stroke, the whistle when you give it gas comes from the jetting or just the pipe?
Mikey Blanco Not sure where that sounds comes from. Probably the exhaust.
I've always wondered the same thing.....
JakeWardell 19 You sure you all don't have whistle tips? Watch this:
ua-cam.com/video/zUXow3d3-b0/v-deo.html
No that isn't it. Far from it. Almost sounds like it's in the engine.... I've heard it on almost every 4 stroke bike or atv.
JakeWardell 19 Kidding aside, I know what you are talking about and never pinpointed what causes that noise.
sir i have a new carb on my scooter..my question is does the pilot jet affects the motorcycle when it is running already? or does it only functions during starting and idling your motorcycle?
Pilot jet circuit has the most effect on idle to 1/8 throttle, however does contribute fuel at higher throttle positions.
+MatthewMCRepair thanks sir..need an advice(160cc scoot)..from 24mm carb i am using keihin pe 28mm now..mj 125 and pj 42..when i twst the throttle its like it the engine would stop a little..i dont know the word to describe it..does this mean i will lower my pj..
Read this: www.howtomotorcyclerepair.com/how-to-size-your-pilot-jet-pilot-screw-explained/
and this: www.howtomotorcyclerepair.com/how-to-tune-a-motorcycle-main-jet/
+MatthewMCRepair thank you sir..God Bless
MatthewMCRepair Hi Mathew. I have just put bigger jets and lifted the needle in my 2014 wr250f. She idles well and generally runs well providing I roll on the throttle slowly. If when riding I accelerate quickly she splutters then fly's away! Can you give me a tip? I have also removed the snorkel. Cheers john in UK
instant hair Dye @ 4:18!!
Lol I seen it
A example of the whistle is at 9:25
Anyone know what i have to change on my 26mm molkt on a lifan 125 to get
rid of bogging? I have tried from 100 to 122 main jets (102 is the
stock one) and nothing is helping, i have also tried 10 sizes bigger
pilot jet, im not sure if it helped, but maybe it did a little. I tried a
cloth around the air cleaner that removed the bog but it doesnt work
well with it on. So do I have to get bigger or smaller main jets and/or
pilot jets? I appreciate if someone could help
On your after video the bike sounds like it's backfiring after you let off. Doesn't the mean it has lean jetting? My bike does the same thing
The bike in the video has the original muffler packing that probably needs to be replaced. Also, the fuel screw was set at 2-2.5 turns out, so it probably should have a larger (maybe).
Keep in mind that some popping is normal with a "race" engine and "open" pipe. Do not try and jet this popping out.
@@HTMR having this issue on my 09 KX250f. Has an extreme amount of popping on decel
@@TheGreenTeam627 Tune the fuel screw, I have a video on that: howtomotorcyclerepair.com/how-to-4-stroke-mx-fuel-screw-adjustment-yzf-crf-kxf-rmz-fcr/
@MatthewMCRepair. My 2008 kx250f is backfiring/Popping alot on deceleration. Iv changed the spark plug and the valves clearances are fine. Do you think a different jetting configuration would do the job. If so any advice on the configuration. Thanks
On decel it is usually a lean condition. Make sure there are no vacuum leaks, exhaust leaks, carb is clean. Tune your fuel screw, I have a video on that. howtomotorcyclerepair.com/how-to-4-stroke-mx-fuel-screw-adjustment-yzf-crf-kxf-rmz-fcr/
Matthew what would you suggest for me to highten my YZ250F rear shock,
I have had it totally dissmantled and no matter how hard i try it wont turn,
I used a spring compressor 2 actually to take the pressure off the spring while trying to turn the bottom spacer and sprayed the hell out of it with WD40 and it still wouldnt turn,
I am 16st 7lb and it feels like i'm riding on the floor when riding this YZF250 lol
At 231 lbs, you need a new stiffer spring. The top should spin, not the bottom retaining plate.
Only the top locking spacer would turn
The bottom spacer wouldnt move at all,
It doesnt matter now as my YZF has been crushed by the police :(
John Jnr The cops crushed your bike?
do you need and air/fuel screw for your carb? I have a yz250f09 and i just noticed my carb doesnt have it but it still runs ok and starts with one kick?
Yours has a stock fuel screw that is well hidden. I would recommend buying an aftermarket screw that is easily accessible.
@@HTMR oh thank you sir! i will definitely check my carb when I can. Good content as always sir. May i suggest that you make a video about fixing intake boots i dont see a lot of videos about that.
On a 03 KTM 450 after complete top end rebuild , cylinder re sleeve, new piston & new titanium valves and new adjustable accelerator pump with every thing tuned and running perfect. one day after a few months my muffler started melting my side plastic muffler cover, then a few days later the bike starts to lose power at higher RPM. Any ideas ?
Thanks for any help on this.
Carb is KEIHIN FCR-MX 39
Carb jets stock 170-40, in shop book 175-48
Jets In as of 03-22 - 178/50
Hey bud, I just bought a 08 crf150r and it has some carb issues. Starts and runs on choke, revs and everything, once choke is completely off it bogs, sputters and dies... any ideas? just went through and cleaned the jets and did a basic clean.
+Gatorsrok Did you remove and clean the pilot jet? Did you remove the fuel screw and clean all carb passages? Blow with compressed air?
+MatthewMCRepair did a pretty damn good job of cleaning out the main pilot and starter jet, got a thin piece of wire from a brush and cleaned them out and sprayed through them, took apart the accelerator pump and cleaned the junk out of their, started playing with the pilot screw and turning it in half turn every time, def likes to backfire and pop turning it in. works better then before but doesn't seem to be squirting fuel out from the accelerator pump nozzle, snapping the throttle it def starves.. just seen water pissing from the weep hole and upon inspection the shaft is grooved and pitted so I'm going to need a new water pump and seals.. till I get them in I won't know how it runs
+Gatorsrok You definitely need to get the acc pump working again, otherwise it will bog/pop.
+MatthewMCRepair just took the car apart again and split it in half and found the acc nozzle squirter, it looks like a jet that you can unscrew but it's actually just a press fit.. (luckily it went back in no problem) of course it was clogged and after 10 minutes with a piece of wire I managed to clean it out. it Works! like I said though, i can't start it as I have the right case halve off and leaking water pump out... ended up stripping the impeller (left hand thread :( and it's aluminum) takes a week to ship :( water pump shaft has some pretty good wear marks and putting were it wore down.. $150 and I got me a new water pump assembly comin... will let u know how she runs on Wednesday
+Gatorsrok Keep me posted!
What is the stock setting on the AP timing screw? Like if you run the screw all the way in, how many turns out would the stock setting be?
Joe, what year make model do you own? The service manual has a procedure for this. It usually involves placing a pin under slide and then adjusting the screw. I'd have to review it myself, it's been a while since I looked at it.
2007 KX250F
Joe Jones Joe, go to my site and type in "kx250f" in search box. I have the free service manual for an 06' and it should be the same procedure for your 07'.
Hi theoretically they say at idle when you push hot start you should i nice strong rev to have your pilot jet and fuel screw correct. I have wr 450 2004 with 48 pilot(stock45) and about 2 turns fuel screw, when i push hot start on idle it slightly revs like a bog or something, what shall i do with my pilot jet or any other jets? If i seat the fuel screw all the way in it will eventually die (doesnt this mean the pilot is also right)? The bike starts and drives fine but how to i get it perfectly jetted?
I don't judge jetting based off how the hot start acts. The hot start should introduce more air, leaning it out, and make the RPM's go up though. Watch this video on proper fuel screw tuning: ua-cam.com/video/kUw41sUQbTY/v-deo.html
So that means im set pretty good with pilot and fuel screw even though the hot start acts like that? Will a needle or main have any effect or shall i just leave it the way it is?
my 2012 yz250f sputters cmming out of corners and when i hit the gas and wack the throttle it sputters as well, the wide open position int great either help!!
Hi Matt,I have a 2010 KX250F with an Athena 290 Big Bore Kit, I got a carb kit from Tokyomods for a big bore, they gave me, 68 leak jet, 45 pilot jet, 178 main jet, NCYU needle, 4th groove down, Fuel screw 2 turns out, I can't get it to start, Please help!
Have you tried different fuel screw positions? 1.5 or 2.5? Also try no choke and pull hot start. They are a pain to start until the fuel screw is tuned.
I have an 07 kx250f and I'm running 175 main 42 pilot not sure what the leak jet is. Do you have any recommendations for all 3 jets that will improve all around accelleration and fix bog ?
www.howtomotorcyclerepair.com/how-to-kx250f-jetting-specs/
Thanks buddy
Love the vid. Was wondering would this also apply to the 05 with the steel frame. I dont think they changed much in the engine but just thought i would ask
What make and model?
05 yamaha yz250f
Yes, then copy the jetting I did for this 06 and it should run much better.
Sweet ill save your other page so i can watch the vidoe when i get the money for the parts. Thanks for the reply even tho its a year later
What elevation are you at?
720'
I am new to this. Thanks for your video. Is all of this jetting related to elevation? I live at 5500 feet, but want to ride in Glamis at an elevation of 335 feet. Would I need to have two jet kits for each of my elevations?
Yes, you would ideally need 2 jetting combos.
@@HTMR Great! Thanks for the reply.
Not full video. Sucks.
+Leyen Sento Labor bills from the mechanic suck too.
+MatthewMCRepair there are a lot full video here, but not yours. Lol
+Leyen Sento *videos
+Leyen Sento OK, if you have any jetting questions feel free to ask.
hello i just installed a hot cams stage 2 and a jebco exhaust . bike has not bin jetted yea but it starts and runs good. should i go up on my jetting ?
Yes, start here: ua-cam.com/video/kUw41sUQbTY/v-deo.html
My bike bogs , so if I adjust the needle jet up , to allow more fuel ,will this take care of problem ???
Watch this: ua-cam.com/video/8SNGm3tcQVY/v-deo.html
Thanks Matthew. It worked like a charm.
I have some questions about my 05 rmz 250. The throttle hangs for 1-2 seconds before going down in rps after I rev it and the idle has to be set REALLY HIGH otherwise it´ll die. Do you think I need a bigger or smaller pilot jet? Or isn´t it even the pilot jet I need to change?
I have some videos on my channel where you can here/see what i mean but I just did a top end rebuild so I can post a new video if you want to see how it runs after the top end rebuild. Thanks
I responded to you on my site.
Do you have a link to the video?
Check your website
@@Freddan9700 curious what was the issue with your bike as i am experiencing the same
Is the part # 5TA-14916-PR or 5TA-14916-V1 for the 08 needle?
well i noticed when you showed the bike running when you were shifting you were not using the clutch you were just ahofting without the clutch witch thats what a quick shifter does wasnt sure if you added one
I just shift without using the clutch. I just let off the throttle a bit and then shift. And no, it's not bad for the tranny.
AdamYasin Vlogs you don’t need the clutch bud
So my power is bogged from quarter throttle to half throttle. Low and top end are perfect, will changing my main jet reduce this? It is it the needle ? I got a little confused haha.
Sounds like you have to play with your needle and/or clip position. This is steady state throttle or twisting it fast?
It's when I hammer down on her, get that classic bog from the 4 stroke. You seemed to eliminate it at the end video.
That is all related to the accelerator pump not squirting enough fuel. Click on blog post under vid description, it goes over how the system works and how to fix it.
would this jetting work at 3300 ft above sea level
ps my bike is an 04 yz250f with an fmf power bomb header and an fmf factory 4 exhaust
currently running
178 main
42 pilot
90 leak jet
stock needle middle clip
currently running fuel screw at 3 turns out to make the bog a little better
I believe that's the stock jetting
It's a good start. You will have to lean it out a bit for higher altitude. Get rid of that 90 leak and throw a 55 in there.
MatthewMCRepair ok it runs pretty good acept for the bog is really bad and it starts kind of hard when it's cold but when it's warmed up starts first kick
Anywhere from 45-55 leak and o-ring mod should rid that bog. Readjust fuel screw for peak idle RPM and that should help with starting as well.
Ok from what I can tell my pilot is a little rich and I have done the oring mod will try a 45 leak jet first then I'll go from there
Hi, i have a crf250r 05 wich bogs really much and has a hard time starting cold. Its too lean mixture, called honda dealer he said go 45 in leak jet and main jet i forgot its like 172 original or if you know what size i should buy please link them! I've got a pro circuit pipe on aswell so if that would make difference on the jetting
+breezeffs jump Here are PC's jetting recommendations for your bike:
www.procircuit.com/jettingspecs2.htm
I would plan on getting an adjustable fuel screw and a 45 pilot just in case. Also, a 45 leak would work good. If it still bogs, slap an oring on it. Visit PC's site for main and needle recommendation.
+MatthewMCRepair hello, thanks for the answer i checked out the site and it seems some jets are wrong written?
Main:170 pilot:42 and leak 70? Should it be 70?
+MatthewMCRepair could you just tell me what jets i should buy? Gonna try leak jet and main jet and do the oring mod, it bogs so bad like in the video orher then that it never bogs..
+breezeffs jump I'd go with a 45 pilot and 45 leak. Run the main they recommend.
Have you got the leak jet part number please??.cheers sam
Here ya go: www.rockymountainatvmc.com/p/930/47202/Keihin-N424-52-Series-Leak-Jet?term=leak+jet
MatthewMCRepair I have a question , I'm using a 175 main ,42 pilot I'm still using a 55 leak jet I'm clip 2 on needle bike runs fine when hot but on a cold start with choke it will start first time but if I try and take choke off after 5 mins it will try and die and run crap.but like I said once warmed up to running temp it's fine....my old crf I'd use choke just to fire then immediately take it off and it would rev up fine am I well off on my needle ?cheers Sam
Sam, you never mentioned year make and model. If you have your fuel screw and pilot jet sized correctly, then it should start cold/hot no problem and run fine everywhere in between. Watch this vid: ua-cam.com/video/kUw41sUQbTY/v-deo.html
Hey man , the bog on my 03 yz250f is pretty bad in the low end and going onto 5th . Is it just an "old bike "problem or what ? Can it be re jetted ?
MatthewMCRepair can you please help me,
Ive got a 2009 crf250x with the CCC mods and a jd jet kit and it backfires just as much as that yz250f in the video and I have swapped out the pilot to a 45 and lowered the needle two slots. It performed horribly with both of them and there was still backfiring so I went back to 42 pilot and 2 up on the needle the way it was before. So what is causing the backfiring? is it normal for a 4 stroke to backfire that much? thankyou.
Exactly the same bike, Same issue. I have all the mods that you listed aswell. Any tips on why it backfires so much?
+KingBandz So you have a 2009 crf250x? What modifications? Location? Pilot jet size? Did you adjust fuel screw? Air leaks? Leak jet size? Answer these so I can better help you.
I have done the airbox mod, swaped the 250x exhaust for a 2005 crf250r can, and JD jet kit. I am in Erie, PA. The pilot is the stock 42. I have attempted to adjust the fuel screw but It starts to not pop at around 3 turns out but its about to fall out but when I put in a 45 pilot even with the fuel screw in all the way it performs wierd. I got it from my friend and everything other than the mods I stated are stock so I'm assuming the leak is stock. I havent looked at any air leaks on the header to pipe or pipe to exhaust yet.
+Foster Schutt Explain how it performs weird with the 45 pilot? Is it a genuine Keihin pilot jet? You need to check for air leaks on carb boot and exhaust.
with the 45 in it sputters on the bottom end, making it feel like a 125 2t powerband. I'm not positive if it is a Keihin pilot jet i will contact my shop tomorrow when they are open. I have checked the intake side of the bike from the filter to the carb for leaks, there are not any,
How do you get a 4 stroke carburetor?
I have a 2004 Crf250r with a fmf powercore 4, I am at 4450 elevation. What jets would I run? Specifically leak jet. My bike falls on its face when I crack the throttle. Already tried o ring mod. Please help!
I'm at 700' and run 45 leak jets and oring mod. Since you are higher up, maybe a 50-55 would work good.
Here is the link to leak jet: www.rockymountainatvmc.com/p/930/47202/Keihin-N424-52-Series-Leak-Jet?term=leak+jet
Also make sure you tune the fuel screw and make sure the pilot is sized correctly, that helps with bog to some extent. Watch this: www.howtomotorcyclerepair.com/how-to-4-stroke-mx-fuel-screw-adjustment-yzf-crf-kxf-rmz-fcr/
my 2007 crf150rb doesn't idle very well and always dies. Bogs lots too. I have stock jetting and slip on fmf ti powercore. Any suggestions?
+brayden renner I responded to your email.
+brayden runner not sure if it applies to dirt bikes but if it bogs you might wanna check the diaphragm in the carbs. I had a sport bike that would bog and I didn't know what was wrong till i checked. turned out it was a torn diaphragm
So how many turns for the air screw 2 an half or 4
ua-cam.com/video/kUw41sUQbTY/v-deo.html
What is bogging at lower throttle or none my bike dies
Watch this: ua-cam.com/video/8SNGm3tcQVY/v-deo.html
You from Chicago?
Yes.
@@HTMR you do any bike repairs on the side ? I’m also from the Chicago land area
@@orenthialhargrove2654 I used to.
do you have a quick shifter on this ?
What is a quick shifter?
I'm at 5100 ft in elevation. What jets do you recommend for my 07' kx250f? I did oring mod, and have a qs3.
Hey did you ever figure that out? I’m at the same elevation dealing with the same problem
Pls someone help me !!!! I have a very hard time trying to start my yz250f .. When I do start it with the choke on after 10+ plus it idles so high !! When I take take the choke off it will take a lot for it to start and when it does it will bog out ... ??? Also it pops so much & back fires . How do I fix this problem bc the bike sounds like shit I need to fix ASAP . Btw it's my first bike .
+Memo T Memo, I responded to your other comment. Email me here and I can help you out:
www.howtomotorcyclerepair.com/contact/
Will the 08 needle work in a 02 yz250f?
Nasty782 Yes. I have no idea on how it will run in your year. Easy and cheap ($15) to try.
bike runs awful the guy who had it before me had timing way out and a pipe that has no name and the yamaha dealer is a joke gave me wrong jets 2 times in a row so its worth the 15$ don't have much to lose
Nasty782 Bike currently runs awful? Don't expect the needle to cure this. I would get it running right and then experiment with jetting. Each needle/jet is stamped, so I would tear down carb and verify against stock.
yeah wasn't expecting just the needle to fix it the carb need tour down for sure.
I want this exact kit how do u recon I'd go getting it and getting it to me
Brodie Chetcuti I responded to your email.
If you're buying oem parts you'll save a LOT of money ordering from partzilla instead of Rocky Mountain
TheChattanoogaBandit I do notice they have better pricing. Thanks for the tip.
thanks so much
thx! it's usefull !
Man I can't believe the difference in the after video! Fucking eh bro! Nice vid!
Yup. Before it falls on it's face and after it will loop you out :)
Watch 08:20 first
Am I the only one wondering why he's not being arrested for ripping around the apartment park?
I've been lucky so far.
Haha bet they love you around there 😂 no fucks given across the fields
not a how to if you don't show the how to portion.
Yes but it's a sample because it says it's a sample.
yet another money making video, pure greed ,
You have no idea buddy. Try making some videos and then get back to me about greed.
step by step how to video on jetting a 4 stroke carburetor, should you not put ( pay to watch how to video) , ,
Lol u gotta pay at the website?? Makes sense
Would be a great video if you would just do it I mean 3/4 of the video was a waste of my day
Doesn't seem like the ideal place to ride lol
No it's not LOL.
Sorry, but let me save everyone some time. This video is not worth watching. Real video behind paywall on another platform.
Waist of time doesn’t explain anything
I’ve got a 08 yz450f always have a problem when I first start it and let it warm up the first blip of the throttle it’s dies. When I start it up again it does not do it it’s always the first blip of throttle any suggestions? I want leaning toward accelerator pump?
Not sure on that one. Runs fine when warm/hot?
Yeah only does it on the first start