Hity carb, just replaced PD19J with PD18j, #34 pilot, #75 main. It is 1-1/4 +_ 1/8 (that 1/8 is like a fine tuner/turner). Redid the float hang, pried it slightly up - - the float is parallel. Throttle response and release, idle return is key on. It never felt this responsive, strong with dead on return to idle RPM. My setting, with your demo, brought my engine sound, crisp, like your baby. The instruction was dead on. I’m on a 50cc. Really cool! Thanks!
Thanks Matthew great instructional video, I’ll be watching. I try to do all my own work on my bike YZ250f, these types of videos are very helpful. I like how your to the point and give the viewer what they need, minimal chatter.
Hi Matthew, thank you for that tutorial with the fuel screen,I will try that with my Yamaha sr 125cc carburetor 1999,I've been having idling problems, my fuel screw "is" fully seated in,therefore, I need to turn it out 2 turns & listen to the rpms, hopefully, should become higher,thank you friend & your engine sounds Awesome, the way your power drops immediately after throttle is the works ,thanks again Matthew 🙂🙂🙂
Excellent explanation, thank you! Ran out of daylight today. My fcr idles excellent but I have a hanging idle when i blip the throttle. When I turned AF screw all the way in the bike didn't die. Maybe a float or cable issue?
Great information and well presented. I just got a used crf450x that smells like it runs rich and even runs like it runs rich and even when the engine is cold it starts better with the hot start lever pulled lol. I’ll be trying just what you did tomorrow. I’m guessing I may need to go to a smaller pilot as rich as it seems, but we’ll see.
FYI you can fit the R&D Racing Flex Jet to the FCR39 even though they say it only fits the MX version. The flex jet is in a better position and easier to adjust. I just used a small rats tail file to remove a little material from the tunnel that the screw runs through, it’s very easy. Some people drill the hole wider, but the interference is not concentric so drilling isn’t required and is a little more risk.
Good job that was probably the best video on that only thing you could have done maybe is show how to use a volt meter for guys that don’t have RPM screens
Man I can't tell you how much you have helped me with my fcr39mm! Dude you are my fcr mx guru thanks for the information. I am doing a drz400 swap.....so much help again thanks!!
I'm buying a used bike tomorrow and I don't know anything about maintanance on the dirt bike yet but it is a 125cc 4 stroke (Japanese brand). I would like some tips on what go adjust or change when I get it
I’m going to visit your website to see where you mentioned if popping or rumbling on deceleration , and or if a backfire snap after full throttle then let off snap, seems somewhat healthy or not? And side note how important is backpressure(a metal screen on end exhaust is just for dirt or really important)? U r a genius
I went to go se my 2004 kx250f & i pressure washed it super good - looks brand new !!! But,,, the damn thing started to run like dook..... (Pressure washer might have turned fuel screw) idk but ,,, it started running hot & melted the airbox & spit out coolant for the first time ive ever seem that happen since ive owned it new..... I could not figure it out - this video nailed it & my bike idles , revs down & runs like before.... Slight bog at initial throttle but managable
This is great man. So easy to follow. I've got a custom fuel screw on the way and now I'm quite confident in what's got to be done. Cheers bro thanx!! Jamie
MatthewMCRepair The screw is in place! Couldn't believe I had to dam near completely disassemble the whole bike to get the carb out though lol.. after rewatching this video I definitely have to adjust my screw though, to many people telling me my idle was too high but after hearing your bikes idle, I'm going to spead it up. I'm riding a 2008 crf450x
My 05 Kx250f has been backfiring like crazy when letting off the gas or decelerating the least little bit. Any ideas? It was revving and returning to idle perfectly and then bam, all of a sudden.
So this is good info but what keeps that screw from falling out? Cause mine is loose and rattled out and gone forever , almost prefer factory one so that it doesn’t fall out, or was mine old and warm out?
Matt I got problem with my 07 rmz250 got to idle but as soon you touch the gas shuts off was a pain to start but now got it to idle has 270 kit stage 3 procircuit kit from cams to titanium valves n exhaust ported n polished whole works like it’s starving for gas carburetor been rebuilt any points on it thanks
Thanks for your video.....can you tell me what would cause one, after adjusting to hang the idle then by itself start stumbling a really low idle then again, change to a hanging fast idle without touching the screw? Hopefully I explained good enough....it just seems to have a mind of its own...lol. thanks in advance.
@HTMR I did...Originally it had a cracked intake boot so I purchased a new one. When spraying the intake boot now with carb cleaner, nothing changes like it did on the cracked intake boot. I think the o-ring on the pilot jet is probably shot allowing it to suck air through a bad o-ring? I just don't know what else would cause it to change so drastically without touching anything.
Can you Help me ? I have a Kawasaki KX450F from 2006, but they did some changes to legalize it in Switzerland (changes are not professionel). Now i try to rebuild it to the original cross. You hava a Video or an advice for the electronics ? Thank you
I love the videos they are very informative. I have a smooth running idle but when I blip the throttle it seems like it hangs rather than going down to idle. And suggestions?
I have a 2014 yz450f with a rebuilt and and had a filled up to the top with antifreeze but for sum reason the bike gets imidietly hot but I haven’t been able to ride because I don’t have a back tire right now so I just leave it idleing
My carb from my 08 yz450 i turned it all the way in and the bike didnt died.. I cant really notice any Diference when ajusting the screw. And on 1/4 trottle She hesitates thanks 4 help
Great vid! 2010 YZ250F. My set fuel screw seems to come loose when I’m riding which then leads to the bike cutting off. Can I replace it or does it need some type of thread lock to hold it in place ?
Im having a problem with my 07 ktm xcf250. It runns on the choke but without the choke it will die when i use the throttle. Jets are clean and accelerator diafram is good. And idea what it mite be. Thank you.
what about the idle screw? my knew pit bike 125cc 4t only starts when the choke is open even when it's hot, I've been testing the screws and I think I've messed up the mixture, it runs fine anyway, it doesn't die at half throttle and it doesn't lock up at full throttle but I have to have the choke open.
I need some help, I bought an 04 suzuki rmz 250 had a bunch of work done to it by previous owner like big bore 290cc and rejetted carb but idk the size.. my issue is it's a major pain to get started have to kick it several times but once it's running it runs great. How do I make it easier to start tho?
I’ve got an 06 wr450. It has a problem with choke. Cold starts are easier with the choke off as for with it on, the bike just dies. warm starts are fine. In general, it just seems like it could run smoother. Looking for any advise before i get around to setting the fuel screw
hey man, great vids. I have a 2009 RMZ 250f that all of the sudden started to rev super high in the air after i hit a jump. NOT GOOD.. the bike rips when i'm riding and sometimes will hang after i let off the throttle going into a corner. all i need to do is blip the throttle real quick and it typically idles right down. very odd. same thing in the air.. if i blip the throttle, the revs come back down. too much work though... i need to fix this. So i put all new jets and seals hoping it just needed a rebuild.. but same thing only now it doesn't want to cruise without sputtering. under load, no problem. she'll scream.. but it still hangs and now won't just cruise down the road without sputtering? fuel screw adjustment too lean?
I have a kxf250 and the idle screw the black plastic one won't turn. I can move it a tiny bit and it just bounces back. Do these jam for any reason? I ask because I need to adjust it as my bike won't stay running when ticking over :(
What of i have the hanging revs coming back to idle but can allso turn fs on all the way and it doesmt die? Also have a bog on snap throttle while on stand
I have an FCR-MX 41 installed on a quad that was originally injected. If I start from 2 turns out and tighten slowly (lean) the idle increases a lot right up until fully seated. As if to suggest more screw turning could further increase the idle. If I start at 2 turns and open the screw (rich) it slows down till it dies at around 3 turns. I believe that means my pilot jet is too big right? I think I have a 45 in there now. I'm thinking about going to a 42. Thanks
@@HTMR Thanks Matthew. I had a 42 in there so going to try a 40 now. Of course I lost the spring on the fuel screw so I can't even try it till next week. arg!
My 2004 yz450f is running best at 1.5 turns out. I had to mess with the idle adjust also, but it's running like a top now. It was still running though when I screwed it all the way in. What does that mean? My pilot jet is too big or too small? Don't know how much it matters but I live at 4500 feet and regularly ride at 8,000-10,000 feet.
I have a question I took my 2007 KLX 300r to my dealership to have the valves shimmed he shamed the intake valves and exhaust valves were fine it kicks on one start now to start up but on deceleration probably from 3 to 4,000 or more RPMs when decelerating it gives a little pop towards the end of the decelerating possibly because files are out and need to be seated a little bit more for us running time it was also 42° out and I've never ran the bike and that cold temperatures to know if it's still gives a little pop on deceleration or is it air fuel mixture screw
Thanks a lot matt, I appreciate it. I'm not to computer oriented and I just stumbled on your comment accidentally. I'm trying to get up to date here in 2017 haha
Thanks for putting this vid up. I did this method and started at 2 turns out, turned it out a decent amount with no change, then i turned it in and when I got within a half turn of being all the way in my idle started to raise and continued to raise untill i had it all the way in. So with it all the way in it didnt stumble, the idle increased. Does that mean im running too rich? This is on a DRZ-400s with a fcr carb upgrade.
MatthewMCRepair Hey brotha, which pilot jet am i messing with? Its an FCR39 off of a KTM quad. It seems like there is 2 pilot jets, one in the intake bell and one inside the carb after you take the bowl off. This is originally off a KTM quad but i bought it off another guy who had it on his DRZ-400SM and he took the pilot jet in the inake bell all the way out. On some instructions for the conversion it says to take it out and on the Thumper Talk instructions it says to have one in. Thanks again for the help.
Quick question. So i have a 2004 honda crf250r and it wont start now i have to build compression on it and then it just backfires and sometimes even almost starts i also noticed i have a fuel line with a significant leak on it do you have any thoughts on what this issue could be ?
Lean fuel screw/pilot jet/ and acc pump shot. I have videos on all these items. What year make model?
4 роки тому
Hi Sir! thanks for share! Excuse my wrong english please! For pilot screw adjustement the higger rpm means stoich AFR? That little partial turn enrichement way that does not rise the rpm, can be cosider that rich range from 14,0:1~12,5:1 before rpm drops? or what AFR range would means? About main jetting, propper or safe combustion, AFR stoich or rich safe range and spark plug reading, are plug chop method the best way to look how many carbon deposits spark plug shows? O² sensor is not easy tool here... how many combustion time a spark plug need to show enough carbon deposits for every jet tested? I tested 5 jet numbers up from stock and not visible ring carbon deposits at insulator base after cut the thread body. thanks a lot Sir!
Hey Matt, say someone messed with my bike and it’s not starting at all. Will tuning it this way be impossible without starting it? Am I wasting energy adjusting and kicking?
This was 7yrs ago so I don’t know if there will be a reply but my bike is weird. It’s a 2002 suzuki quad runner and if I turn it in all the way it just revs up and doesn’t die and idle hangs but if I turn it out to factory setting (1-3/8) the idle still hangs. I turn it out to 4 turns and it idle better but shoots some black smoke. But when I ride it at times on the 4 turns out it hangs the idle sometimes. I have no idea if it’s running too rich or too lean.
How can you tell it's seated when you turn it it? Is there resistance? I don't want to turn my in too much as damage the thin tip needle? Thanks for the video -helps understand how to tune and more importantly which direction to turn for rich/lean.
I was wondering if you maybe able to help, I have an Rmz 250 for 08, I've shimmed it to the correct clearance, new piston etc but have contradictory scenarios, I'm blowing Black smoke ( rich ) but its running on ( lean ) any suggestions? Thanks
@@HTMR Thanks for getting back to me. It revs on after releasing the throttle, I've taken the steps you suggested on the video, and there is a slight improvement, however I'm at 2 and a half turns and it still does it, I've put in the 45 pilot jet, I've tried a lot of things to stop it, and cannot get it to stop reving after the throttle is off, it gently reduces revs after around 5-10 seconds. Any help is really appreciated.
Hi Matthew, I have a keihin fcr carb and a tusk adjustable fuel screw. Bike runs great but does not stay idling without a little extra throttle. There is no idle screw, only a fuel screw. Is it okay to adjust the fuel screw to get the idle up, or no? It runs great so I don’t want to mess with it if it won’t help.
the idle adjustment is a flex screw the threaded end goes in where u connect the throttle cables the opposite end goes to the left side of the carb and attaches to the carb bowl screws
ive got an issue with my yz450f, when i press choke back in bike dies, if i throttle and push it in, it's like gas exploding in the exhaust could it be something going on my valves or the fuel, sorry for asking, im new to 4-Stroke :)
I have a yz450F runs good but back fires when u decelerate. Could this be the problem or could it one of the jets? The valves are good I checked them as well.
So I have a 2008 yz250f I rebuilt the carb and put all new stock jets back in it. it runs fine except when I crack the throttle from idle it chokes and will die. I'm not sure what the problem is. any information would be helpful. thanks
I did this and I changed the carb changed the spark plug new intake and it still won’t accelerate is there any other reason for my bike won’t accelerate could it be a piston or a throttle cable I’m out of ideas now
I have another question. My 2002 crf450r owners manual says stock pilot jet is a 45 and the main jet is a 175. I pulled the jet out thats at the bottom of the carb. It's labeled 45, but everywhere I'm looking it says the jet I pulled is the main jet, so where is the confusion
Hey my 04 crf450r doesn’t wanna idle when I set the carb to it’s settings (2 an a half turns out on idle screw an fuel mixture an 2 turns out it’ll rev to the sky but it starts very easy but when I get the idle to be low but I have to give it gas so it won’t die it’ll be very hard to start
hey matt i have an 05 kx250f and its had trouble starting. the hot start plunger screw (plastic) stripped out, and it had a 45 pilot in it. just wondering if the leakage from the stripped screw would affect the bike so much to the point it will not start?? i have to blip the throttle to spray some fuel in the motor before hand which will sometimes turn it over, then it quickly revs and immediately bogs after to a stall even if you give it throttle. jets weren't clogged and sliding plate was installed correctly
MatthewMCRepair the bikes all fixed now, put too much grease around/in the tps when i did the carb rebuild. i found that running it with the tps unplugged adds some good throttle response but can affect the idle a bit. i ordered a metal nut for the hot start so that should be all set now. feel free to spread the word on that tho, many people have the same problem i did. great videos and thanks for the help!!
Hey I have a Yamaha 2002 wr250 f the screw you are turning what is the black one above that where does that need to be set at I can't start my bike now someone messed with it and opened it all the way please reply
Im having a little trouble with a wr 450 . If i close the choke the bike shuts of. I already cleaned the pilot jet but the problem persist. Any suggestions?
I have a 2014 Yamaha YZ450. Its starts and idles with the hot start on but as soon as I push it in to ride the bike will not idle on it's own. But as long as there is constant throttle it runs fine. Any idea how to fix this or what needs to be corrected. Any help would be great. Thanks in advance.
Hity carb, just replaced PD19J with PD18j, #34 pilot, #75 main. It is 1-1/4 +_ 1/8 (that 1/8 is like a fine tuner/turner). Redid the float hang, pried it slightly up - - the float is parallel. Throttle response and release, idle return is key on. It never felt this responsive, strong with dead on return to idle RPM. My setting, with your demo, brought my engine sound, crisp, like your baby. The instruction was dead on. I’m on a 50cc. Really cool! Thanks!
Thanks so much man, my bike would run to hot and never want to start. Now I turned it to 2 and it’s less hot has more power and starts up
Thanks Matthew great instructional video, I’ll be watching. I try to do all my own work on my bike YZ250f, these types of videos are very helpful. I like how your to the point and give the viewer what they need, minimal chatter.
Did it work after u adjusted the screw ?
Hi Matthew, thank you for that tutorial with the fuel screen,I will try that with my Yamaha sr 125cc carburetor 1999,I've been having idling problems, my fuel screw "is" fully seated in,therefore, I need to turn it out 2 turns & listen to the rpms, hopefully, should become higher,thank you friend & your engine sounds Awesome, the way your power drops immediately after throttle is the works ,thanks again Matthew 🙂🙂🙂
Best explanation to this 4 stroke carb tuning. Great video thank you.
Thanks, Exactly what I needed to solve my throttle hanging up on my freshly rebuild 250F
Same
did u just turn the fuel screw and it fixed it ?
@@rileyduff6604 yes. I bought an aftermarket fuel screw, installed it and followed his instructions. problem solved and I learned something.
Brian Rose cheers bro yeah i fixed mine but i still have stock fuel screw was so hard but i got it
Excellent explanation, thank you! Ran out of daylight today. My fcr idles excellent but I have a hanging idle when i blip the throttle. When I turned AF screw all the way in the bike didn't die. Maybe a float or cable issue?
Year make model? Stock pilot jet? Any mods?
@@HTMR 2006 yfz450 (ATV) bill balance edition 48 pilot jet, 165 main jet, K&N filter, EHS lid, heads P/P, FCR is bored. cam mod , AC pump mod (zip)
Awesome and to the point, thanks! I found out my hot start was corroded in the open position and causing a similar popping..
What is a hot start? My rmz 250 pops a little But when i start it the pipe gets red
Great video just bought a bike an it wouldn’t start , did this and she fired right up easy an to the point 🤟
Great information and well presented. I just got a used crf450x that smells like it runs rich and even runs like it runs rich and even when the engine is cold it starts better with the hot start lever pulled lol. I’ll be trying just what you did tomorrow. I’m guessing I may need to go to a smaller pilot as rich as it seems, but we’ll see.
How are you tuning a cold carb? Did you warm it up ?
Dude my kx250f runs perfect now thanks the fuel screws was all the way up
FYI you can fit the R&D Racing Flex Jet to the FCR39 even though they say it only fits the MX version. The flex jet is in a better position and easier to adjust. I just used a small rats tail file to remove a little material from the tunnel that the screw runs through, it’s very easy. Some people drill the hole wider, but the interference is not concentric so drilling isn’t required and is a little more risk.
Good job that was probably the best video on that only thing you could have done maybe is show how to use a volt meter for guys that don’t have RPM screens
Just tune by ear then.
Man I can't tell you how much you have helped me with my fcr39mm! Dude you are my fcr mx guru thanks for the information. I am doing a drz400 swap.....so much help again thanks!!
Thanks for the vid, One question, if the screw Is all screw in, (leaning) the bike must stop?
I'm buying a used bike tomorrow and I don't know anything about maintanance on the dirt bike yet but it is a 125cc 4 stroke (Japanese brand). I would like some tips on what go adjust or change when I get it
125cc what? Best thing to do is get a service manual and read the maintenance section. It will explain what you need to do.
I’m going to visit your website to see where you mentioned if popping or rumbling on deceleration , and or if a backfire snap after full throttle then let off snap, seems somewhat healthy or not?
And side note how important is backpressure(a metal screen on end exhaust is just for dirt or really important)?
U r a genius
I'm gonna try it when i get home today...hopefully it will help with the bike not wanting to idle
I went to go se my 2004 kx250f & i pressure washed it super good - looks brand new !!! But,,, the damn thing started to run like dook..... (Pressure washer might have turned fuel screw) idk but ,,, it started running hot & melted the airbox & spit out coolant for the first time ive ever seem that happen since ive owned it new..... I could not figure it out - this video nailed it & my bike idles , revs down & runs like before.... Slight bog at initial throttle but managable
I have vids to clear the bog.
This is great man. So easy to follow. I've got a custom fuel screw on the way and now I'm quite confident in what's got to be done.
Cheers bro thanx!!
Jamie
Cool. Keep me posted on outcome.
MatthewMCRepair The screw is in place! Couldn't believe I had to dam near completely disassemble the whole bike to get the carb out though lol.. after rewatching this video I definitely have to adjust my screw though, to many people telling me my idle was too high but after hearing your bikes idle, I'm going to spead it up. I'm riding a 2008 crf450x
Yeah, it takes some effort to get to these carbs.
My quad seemed to get hot really fast after new exhaust and better filter im guessing it’s funning to lean ? To much air not enough gas ?
If in doubt rule it out.
Runs better but still popping on decel.
I care not as the power is smooth.
Great info, thanks !
My 05 Kx250f has been backfiring like crazy when letting off the gas or decelerating the least little bit. Any ideas? It was revving and returning to idle perfectly and then bam, all of a sudden.
So this is good info but what keeps that screw from falling out? Cause mine is loose and rattled out and gone forever , almost prefer factory one so that it doesn’t fall out, or was mine old and warm out?
There is a spring to keep tension on threads.
Matt I got problem with my 07 rmz250 got to idle but as soon you touch the gas shuts off was a pain to start but now got it to idle has 270 kit stage 3 procircuit kit from cams to titanium valves n exhaust ported n polished whole works like it’s starving for gas carburetor been rebuilt any points on it thanks
On my '05 WR 450 i have it running perfect but alot of popping on Decel, what can I adjust.. Ty..
Thanks for your video.....can you tell me what would cause one, after adjusting to hang the idle then by itself start stumbling a really low idle then again, change to a hanging fast idle without touching the screw? Hopefully I explained good enough....it just seems to have a mind of its own...lol. thanks in advance.
Did you check for vacuum leaks?
@HTMR I did...Originally it had a cracked intake boot so I purchased a new one. When spraying the intake boot now with carb cleaner, nothing changes like it did on the cracked intake boot. I think the o-ring on the pilot jet is probably shot allowing it to suck air through a bad o-ring? I just don't know what else would cause it to change so drastically without touching anything.
@@dgmenace73 Year make model? What is stock and current pilot jet size? Fuel screw setting?
@HTMR I ordered a stock pilot jet and its running like a charm now. Thanks
Nice! Most of the recent carbs, especially the ones with a plug over the set screw, come set too lean for emissions reasons.
Can you Help me ? I have a Kawasaki KX450F from 2006, but they did some changes to legalize it in Switzerland (changes are not professionel).
Now i try to rebuild it to the original cross. You hava a Video or an advice for the electronics ?
Thank you
I love the videos they are very informative. I have a smooth running idle but when I blip the throttle it seems like it hangs rather than going down to idle. And suggestions?
You have a lean hanging idle. Adjust fuel screw richer.
On which carb must i start if have 2 carbs? Suzuki intruder vs 800 1994
I have a 2014 yz450f with a rebuilt and and had a filled up to the top with antifreeze but for sum reason the bike gets imidietly hot but I haven’t been able to ride because I don’t have a back tire right now so I just leave it idleing
wow that is snappy and beautiful!!!
My carb from my 08 yz450 i turned it all the way in and the bike didnt died.. I cant really notice any Diference when ajusting the screw. And on 1/4 trottle She hesitates thanks 4 help
BOA noite meu ktm sxf450 quando está mais quente fica a afogar tem alguma ideia da solução ?
Great vid!
2010 YZ250F. My set fuel screw seems to come loose when I’m riding which then leads to the bike cutting off. Can I replace it or does it need some type of thread lock to hold it in place ?
How many turns out are you?
Im having a problem with my 07 ktm xcf250. It runns on the choke but without the choke it will die when i use the throttle. Jets are clean and accelerator diafram is good. And idea what it mite be.
Thank you.
hey man, my bike will bump start but not kick start. any suggestions? 04 kx250f
2021 Rmz 450 revs too high during cold start when choked?
what about the idle screw? my knew pit bike 125cc 4t only starts when the choke is open even when it's hot, I've been testing the screws and I think I've messed up the mixture, it runs fine anyway, it doesn't die at half throttle and it doesn't lock up at full throttle but I have to have the choke open.
I need some help, I bought an 04 suzuki rmz 250 had a bunch of work done to it by previous owner like big bore 290cc and rejetted carb but idk the size.. my issue is it's a major pain to get started have to kick it several times but once it's running it runs great. How do I make it easier to start tho?
Start by tuning the fuel screw.
AWESOME video... I'm an old guy, and new to this.... Mine has #'s 1-4 on it, so one "whole turn" is 1 ALL THE WAY AROUND back to 1 correct? Thank you!
Yes that is considered one turn
@@HTMR damn 5year old video, STILL helping others. Appreciate it. Have a good one.
How about the air idle mix how many turns min. And max?
I’ve got an 06 wr450. It has a problem with choke. Cold starts are easier with the choke off as for with it on, the bike just dies. warm starts are fine. In general, it just seems like it could run smoother. Looking for any advise before i get around to setting the fuel screw
That happens when fuel screw and/or pilot jet is too rich.
hey man, great vids. I have a 2009 RMZ 250f that all of the sudden started to rev super high in the air after i hit a jump. NOT GOOD.. the bike rips when i'm riding and sometimes will hang after i let off the throttle going into a corner. all i need to do is blip the throttle real quick and it typically idles right down. very odd. same thing in the air.. if i blip the throttle, the revs come back down. too much work though... i need to fix this. So i put all new jets and seals hoping it just needed a rebuild.. but same thing only now it doesn't want to cruise without sputtering. under load, no problem. she'll scream.. but it still hangs and now won't just cruise down the road without sputtering? fuel screw adjustment too lean?
Sa.e problem on my 07 rmz 250 throttle hanging up too long
My 2004 honda crf250x with a fcr carburetor has a 155 pilot and 42 main jet and the fuel screw and needle clip in position #5
Your videos are very helpful! I’m doing a FCR on my LTZ400 would the adjustments be the same for my quad? Fcr is from a yfz450 .
Yes, this applies for all FCR carbs.
Screwing it out makes it rich not lean
Yes.
Great video, could you do a Honda Navi is a 4 stroke engine too!
I have a 09 Yz450f with a full fmf exhaust, It backfires during deceleration so do I turn the screw more rich or more lean?
Richer. I usually install one size larger pilot jet also.
@@HTMR Thanks bro
I have a kxf250 and the idle screw the black plastic one won't turn. I can move it a tiny bit and it just bounces back. Do these jam for any reason? I ask because I need to adjust it as my bike won't stay running when ticking over :(
Thanks this will help I hope. If not I have another problem.
is the carburetor Same as pz30b carburetor with acceleration pump and slide
got a kawa 2011 250f there comming fuel to the karburator but not feeding it to the engine whys that?
Need help, I think I
have a 49cc 4 stroke Motor. How do I connect and idle the carburator?
You are the man !! Very well explained thanks
What of i have the hanging revs coming back to idle but can allso turn fs on all the way and it doesmt die? Also have a bog on snap throttle while on stand
I have an FCR-MX 41 installed on a quad that was originally injected. If I start from 2 turns out and tighten slowly (lean) the idle increases a lot right up until fully seated. As if to suggest more screw turning could further increase the idle. If I start at 2 turns and open the screw (rich) it slows down till it dies at around 3 turns. I believe that means my pilot jet is too big right? I think I have a 45 in there now. I'm thinking about going to a 42. Thanks
Yes, maybe even a 40.
@@HTMR Thanks Matthew. I had a 42 in there so going to try a 40 now. Of course I lost the spring on the fuel screw so I can't even try it till next week. arg!
@@jayp7043 Try a spring from a pen for the time being.
@@HTMR that is a great idea. I just got this post today and somehow the new fuel screws came yesterday. Thanks!
Is it the same for the twin air
My 2004 yz450f is running best at 1.5 turns out. I had to mess with the idle adjust also, but it's running like a top now. It was still running though when I screwed it all the way in. What does that mean? My pilot jet is too big or too small? Don't know how much it matters but I live at 4500 feet and regularly ride at 8,000-10,000 feet.
Pilot jet too rich.
Matt, great video. how would I go about draining the fuel on my 06 kx250f?
Why drain it?? Loosen the 17mm bowl nut.
I have a question I took my 2007 KLX 300r to my dealership to have the valves shimmed he shamed the intake valves and exhaust valves were fine it kicks on one start now to start up but on deceleration probably from 3 to 4,000 or more RPMs when decelerating it gives a little pop towards the end of the decelerating possibly because files are out and need to be seated a little bit more for us running time it was also 42° out and I've never ran the bike and that cold temperatures to know if it's still gives a little pop on deceleration or is it air fuel mixture screw
So if my rpm drops slowly it's rich?
great video, helped me a lot. regrats from brazil
After a blip of throttle yes.
@@HTMR 1:35 but you said if rpms hang you gotta richen it up. So is it rich or lean if the rpms hang?
@@dantsy6397 hanging rpm is lean
Mein, this is the perfect explanation. Best ever 💥💥💥💥💥💥💥💥
Thanks a lot matt, I appreciate it. I'm not to computer oriented and I just stumbled on your comment accidentally. I'm trying to get up to date here in 2017 haha
Thanks for putting this vid up. I did this method and started at 2 turns out, turned it out a decent amount with no change, then i turned it in and when I got within a half turn of being all the way in my idle started to raise and continued to raise untill i had it all the way in. So with it all the way in it didnt stumble, the idle increased. Does that mean im running too rich? This is on a DRZ-400s with a fcr carb upgrade.
Yes, I'd drop the pilot jet 2 sizes.
MatthewMCRepair Cool, thanks for the advice and the video.
MatthewMCRepair Hey brotha, which pilot jet am i messing with? Its an FCR39 off of a KTM quad. It seems like there is 2 pilot jets, one in the intake bell and one inside the carb after you take the bowl off. This is originally off a KTM quad but i bought it off another guy who had it on his DRZ-400SM and he took the pilot jet in the inake bell all the way out. On some instructions for the conversion it says to take it out and on the Thumper Talk instructions it says to have one in. Thanks again for the help.
The one in the bell is an air jet, I usually don't mess with that.
MatthewMCRepair cool thanks again brother!!
Your idle screw is the fuel screw what you on about? How can you have an idle screw and a fuel screw? You have an idle/fuel screw and an air screw
Quick question. So i have a 2004 honda crf250r and it wont start now i have to build compression on it and then it just backfires and sometimes even almost starts i also noticed i have a fuel line with a significant leak on it do you have any thoughts on what this issue could be ?
First, take care of the fuel leak. I don't know what the problem is but I'm willing to bet the carb is dirty and improperly tuned (fuel screw).
Quick question mate...I got a 4 stroke 250..its new when I pull the throttle back fast it cuts out do I need to screw the screw in or out on carb
Lean fuel screw/pilot jet/ and acc pump shot. I have videos on all these items. What year make model?
Hi Sir! thanks for share!
Excuse my wrong english please!
For pilot screw adjustement the higger rpm means stoich AFR?
That little partial turn enrichement way that does not rise the rpm, can be cosider that rich range from 14,0:1~12,5:1 before rpm drops? or what AFR range would means?
About main jetting, propper or safe combustion, AFR stoich or rich safe range and spark plug reading, are plug chop method the best way to look how many carbon deposits spark plug shows? O² sensor is not easy tool here...
how many combustion time a spark plug need to show enough carbon deposits for every jet tested? I tested 5 jet numbers up from stock and not visible ring carbon deposits at insulator base after cut the thread body.
thanks a lot Sir!
Hey Matt, say someone messed with my bike and it’s not starting at all. Will tuning it this way be impossible without starting it? Am I wasting energy adjusting and kicking?
This was 7yrs ago so I don’t know if there will be a reply but my bike is weird. It’s a 2002 suzuki quad runner and if I turn it in all the way it just revs up and doesn’t die and idle hangs but if I turn it out to factory setting (1-3/8) the idle still hangs. I turn it out to 4 turns and it idle better but shoots some black smoke. But when I ride it at times on the 4 turns out it hangs the idle sometimes. I have no idea if it’s running too rich or too lean.
Weird. When was the last time the carb was cleaned? Check for vacuum leaks also.
How can you tell it's seated when you turn it it? Is there resistance? I don't want to turn my in too much as damage the thin tip needle? Thanks for the video -helps understand how to tune and more importantly which direction to turn for rich/lean.
Use light finger torque and seat it until it stops. Use very little force and you will be OK.
I was wondering if you maybe able to help, I have an Rmz 250 for 08, I've shimmed it to the correct clearance, new piston etc but have contradictory scenarios, I'm blowing Black smoke ( rich ) but its running on ( lean ) any suggestions?
Thanks
What do you mean running on?
@@HTMR
Thanks for getting back to me.
It revs on after releasing the throttle, I've taken the steps you suggested on the video, and there is a slight improvement, however I'm at 2 and a half turns and it still does it, I've put in the 45 pilot jet, I've tried a lot of things to stop it, and cannot get it to stop reving after the throttle is off, it gently reduces revs after around 5-10 seconds.
Any help is really appreciated.
@@brendanholmes6650 Inspect the throttle valve vacuum release plate seal. Make sure it is installed correctly also.
@@HTMR
Thanks very much, il look into that straight away, appreciate your time
Hi Matthew, I have a keihin fcr carb and a tusk adjustable fuel screw. Bike runs great but does not stay idling without a little extra throttle. There is no idle screw, only a fuel screw. Is it okay to adjust the fuel screw to get the idle up, or no? It runs great so I don’t want to mess with it if it won’t help.
No, do not adjust fuel screw to adjust idle. That carb should have an idle adjust, if not, buy the part.
the idle adjustment is a flex screw the threaded end goes in where u connect the throttle cables the opposite end goes to the left side of the carb and attaches to the carb bowl screws
My xr650l runs good at about 3 turns out... Is that ok
Yes
@@HTMR thanks bro... I did go ahead and order a 55 pilot jet
Sweeeet video!! Thanks very helpful 👍🏾
hello, new to riding. would this help with bogging?
Yes somewhat. You want to tune the AP timing and reduce the leak jet size; howtomotorcyclerepair.com/fcraptiming/
ive got an issue with my yz450f, when i press choke back in bike dies, if i throttle and push it in, it's like gas exploding in the exhaust could it be something going on my valves or the fuel, sorry for asking, im new to 4-Stroke :)
I have a yz450F runs good but back fires when u decelerate. Could this be the problem or could it one of the jets? The valves are good I checked them as well.
Could be lean, or exhaust leak, or blown out muff packing.
MatthewMCRepair thanks I appreciate it I’m gonna check my spark plug after I ride it
Just got a 2008 YZ 450 and it will not run off choke I got a new pilot jet but I don't know if it's just the adjustment screw
Could be dirty pilot jet and improper fuel screw setting. Best to pull carb and clean it if bike is new to you.
So I have a 2008 yz250f I rebuilt the carb and put all new stock jets back in it. it runs fine except when I crack the throttle from idle it chokes and will die. I'm not sure what the problem is. any information would be helpful. thanks
You need a smaller leak jet: ua-cam.com/video/BczznidaDz8/v-deo.html
I did this and I changed the carb changed the spark plug new intake and it still won’t accelerate is there any other reason for my bike won’t accelerate could it be a piston or a throttle cable I’m out of ideas now
What bike? What is the exact problem?
I will try this out on my crf, good video
Will this help me on starting my bike hot? Because its a nightmare to start hot? But 2nd kick cold
It can for sure.
Do you do it with choke in or out?
I have another question. My 2002 crf450r owners manual says stock pilot jet is a 45 and the main jet is a 175. I pulled the jet out thats at the bottom of the carb. It's labeled 45, but everywhere I'm looking it says the jet I pulled is the main jet, so where is the confusion
The 6mm hex is the main jet.
Hey my 04 crf450r doesn’t wanna idle when I set the carb to it’s settings (2 an a half turns out on idle screw an fuel mixture an 2 turns out it’ll rev to the sky but it starts very easy but when I get the idle to be low but I have to give it gas so it won’t die it’ll be very hard to start
Andy idea what it is?
hey matt i have an 05 kx250f and its had trouble starting. the hot start plunger screw (plastic) stripped out, and it had a 45 pilot in it. just wondering if the leakage from the stripped screw would affect the bike so much to the point it will not start?? i have to blip the throttle to spray some fuel in the motor before hand which will sometimes turn it over, then it quickly revs and immediately bogs after to a stall even if you give it throttle. jets weren't clogged and sliding plate was installed correctly
Is the hot start plunger fully seated even though the nut is cracked?
MatthewMCRepair the bikes all fixed now, put too much grease around/in the tps when i did the carb rebuild. i found that running it with the tps unplugged adds some good throttle response but can affect the idle a bit. i ordered a metal nut for the hot start so that should be all set now. feel free to spread the word on that tho, many people have the same problem i did. great videos and thanks for the help!!
Glad you figured it out.
Thanks for the help brother from Sacramento, Ca.
What does it mean when i blip my throttle and my bike dies? Great video by the way!
Bogging out or a misfire
Would this fix a bike that feels like it’s sputtering and backfiring?
Hey I have a Yamaha 2002 wr250 f the screw you are turning what is the black one above that where does that need to be set at I can't start my bike now someone messed with it and opened it all the way please reply
Idle speed.
Im having a little trouble with a wr 450 . If i close the choke the bike shuts of. I already cleaned the pilot jet but the problem persist. Any suggestions?
Is the idle adjusted properly?
@@HTMR i fixed it! It put a new pilot jet one size bigger! Thanks anyway
Thank You for the video. I just got a full yoshimura exhaust for my yz450f . Do i need to change jets size or any other carb adjustments?
+Gennaro Scotti Yes. Visit their site to see if they have recommendations on where to start.
I have a 2014 Yamaha YZ450. Its starts and idles with the hot start on but as soon as I push it in to ride the bike will not idle on it's own. But as long as there is constant throttle it runs fine. Any idea how to fix this or what needs to be corrected. Any help would be great. Thanks in advance.
If you are using the hot start then the fuel mixture screw is too RICH. Lean out the pilot jet and/or the fuel screw setting.
Thanks for responding l will give it a try
Do you have the idle revs low just for tuning and then turn it up after tuning or that low idle is how it should be?
Low just for tuning so you can easily hear changes. Then raise idle after done.
Can this cause ticking noise ? Other then valve or tensioner
so when ur talking abt the fuel screw is out from something, r u talking abt out from all the way in?