Thanks Matthew!! Working on my 2003 Kx250. The bolts on the carbs are so tight. My bike has been sitting for 4 yrs. Getting back to riding this summer been awhile. Bought a overpriced JD jet kit and learned my lesson but least I didn't have to play with the jet sizes and needles. Kx250 there really is no room to work. Couldn't even put a spark plug in without taking everything off.
I just started jetting this bike. So far I have leaned the pilot, new leaner needle, and leaner main. I have been doing it by plug reading and engine tone. I'll come out with a vid & post soon.
Thanks for this, just picked up a KX250 and figured I should clean the carb out and check the jetting. This is a nice show and tell which really helped. I am sure you know this but if you have issues with seized bolts/screws just tap them with a hammer a few times and try again.
+MatthewMCRepair Do those work well? They look like they have the same design as those auto center punches. Side note, my KX refuses to idle when hot or cold and smokes like it's running super rich. Other than that it runs great and pulls hard. I've adjusted the idle and mixture screws to no avail. I figured a gummed up pilot but the carb is super clean (although did perform cleaning anyway). Any ideas on the idle issue? Thinking the smoke maybe a crank seal. I have very limited 2 stroke experience though so don't want to pull the case when it maybe something simple I am missing.
+308at95630 The drivers work OK for all but the most stubborn fasteners. Check your plug and see if it is oil fouled. If it is, proceed with a pressure test and see if the RH seal is leaking.
No, needle clip position has little effect on main jet. FYI, clip position is always referenced from top clip. So if you read a manual that states 2nd position, they mean 2nd position from top. For main jet tuning, do a plug chop at full throttle and cut plug open. The fire ring should be about 2mm or so tall.
It seems like they all rev high on start up with choke. A couple of guys on the forums toggle the choke on/off several times until the engine calms down. I am in the process of jetting this bike and went from 52 to 48 on the pilot and it no longer rev quite as high during start up.
Bob, in vid description, I have a link to a blog post which includes more info, including a download link for the service manual. I did not cover float level in this video, however the manual will walk you through it. I have a 160 main which is stock for my model. I just ordered a bunch of brass and a new needle, so stay tuned for a jetting vid.
The throttle position sensor is used to sense when to cut fuel with the solenoid valve located on the RH side of carb. Make sure carb is clean, write down jetting, and adjust pilot screw. Maybe that will cure your bog.
+Alex McLeod Thanks, Alex. Yes, you are going to go through everything I went through. I'm about to do a top & bottom end this week, so vids should be available in 2 months.
+MatthewMCRepair My bottom end is in a very bad way and cylinder needs replating. There are some pics on my Flickr page flickr.com/alexmcleod I haven't split the case yet but do you think it's possible to bring the bottom end back from the dead? New crank assembly, new bearings, new seals and vapour blast the insides of the cases?
+Alex McLeod Alex, holy crap what happened to that motor??? Just looked at your pics. I wouldn't buy any parts until you have that completely apart and asses the corrosion on the cases. Looks like they are really pitted. Of course anything can be fixed, it just depends on how much money you want to put into it.
+MatthewMCRepair Yeah it's bad, top end blew and the previous owner opened it up and left it sitting there. I bought the whole bike for cheap last week and like you say I'm gonna wait til I get the cases split apart and have a really good look at everything. I'm on the lookout for another complete bottom end as well so I'll see what comes up! Thanks for the advice :)
1/4-1/2 throttle will be the slide cutaway and needle taper. The pilot is really for idle to 1/8, although may help your situation. How many turns out is your pilot screw? Does the bike bog?
Hi! I want to thank you because i have little problem about throttle responce and this helped me A LOT installing carb repair kit. I have kx 250 2000 model with same carb as yours, share all you have. :) thx alot once more.im interested cylinder and piston change as well because i need to change soon piston and ring/rings
Hey Matthew can I have your email , I just bought the same bike and the carburetor looks a complete mess to me and I don’t have to much knowledge with that , please help thanks ..?
Sounds like the "detent" is worn out. You could replace the choke assy. I can take it off choke right after it starts. Sputs on throttle? Is it running rich?
I have a 1970 honda sl100 and when I cleaned my carb it was REALLY bad I had to soak it in penetrating fluid overnight just to get the bowl clean. my needle was stuck so I heated it up and pushed on it. After that it came loose and now it runs. I ordered a rebuild kit cuz my float was leaking and somehow dented
Just subscribed as I have purchased a 96 KX250. Needed a bike to ride with my 11yo and his TTr90. I've already watched the carb clean vid twice. I WILL be watching it a few more times. The bike has what was explained to me weighted flywheel to even out the bottom end. This was an enduro racers bike. I'd like to keep it until I figure out how it feels. At 51 I certainly am NOT looking to race and will be doing quite a bit of trail riding but also as much in the pit with my son. We live on the South Jersey shore in the Pine Barrons. If you have any knowledge of this sort of device and the ease or difficulty in removal, that info would be of great help. Thanks!!! GREAT VIDEOS!!!
The Sopranos "Pine Barrons" was one of my fav episodes...LOL. If you are going to be trail riding and putting around with your son, leave the flywheel weight on. It will help lug the motor at a lower RPM and tame the hit. I ride MX, and bought a flywheel weight for cheap and plan to try it out. I have trouble getting traction and hope the extra weight will help. Hopefully I should have an install vid soon.
You stated when installing a Pro Circuit pipe I should go down "one" on the main jet. Would you recommend the 158 or the 155? Thank you for the vids. They are a great help.
Run the plug recommended by your make, nothing more. I haven't found any major improvements by spending more on a plug. Are you fouling plugs? Once jetting is spot on, a plug will last a long time.
I bought a 2000 cr250r in June. bike ran great, better than any other bike I've owned. The powerband especially was shocking, it would engage smooth the bike would pull hard, harder than my kx500. The first time I added gas, the bike ran like shit. Throttle lag, lurching and stopping, even tho its the same mix the previous owner used. So far ive replaced the piston/rings/etc, cleaned the carb, taken apart the powervalve, cleaned the carbon, changed the plug, clutch plates/springs, case oil, reeds, and have tried different premix ratios and oil. Bike runs better, but is not even close to as powerful as when i first got it. ive started it up and watched the powervalve move, but its just not there in the sense of power. i just ordered new main jets in a last ditch effort, but obviously i dont know what the issue is. any insight would be helpful. Thanks :)
The reeds where ok but i replaced them anyway. Not much of a difference afterward. Plugs were wet and black. recently they arent as black(ive switched to better gas and oil) I will go to a shop and have them compression test. Thanks :) MatthewMCRepair
i just got a 2002 kx 250 same monster graphics love the visz but the 2 things i was hopin for in this vid you didnt show what the main jet size is i have a 165 i was woundering if that was stock and the float level i think mine is down to far it doesnt sit level with the frame if i hold it upside down it sits further down like if it would end up flooding ,not sure if thats normal
I have a rm250 runs and starts first kick has good compression but as soon as I turn the choke of it dies. I've cleaned the carb really good I don't know what the heck to do i'm not super inclined but the bike is all apart I changed the plug new fuel and cleaned the air filter. Please help..
alright bro thanks alot , cuz i tried to turn it on yesterday and it would start for 5 seconds with it bogs out the spark is fine , the compression is fine so would it be idle adjusting and a good clean for the carb ? thanks
i just got a 2002 kx 250 and the choke button doesnt stay up on warm up do i need a new one and when i ride it kind of sputs when im on the throttle but it still gos fast what you think it might be
Quick question! so I took the carb off cleaned it, i followed your video exactly & this was a very easy job to do btw thank you for the content anyway. the bike ran great before I took it apart n cleaned it. now its back tog it won't start. I made the mistake of not counting air screw turns and idle screw turns of where it was before I dis assembled. I got great spark compression as I checked. now its fuel n air prob... I cant get it to start even with a new plug. its 52 pilot and 160 main stock kx, clip is in pos #2 I did 2 turns out from ceet. still won't start plug is soaked every time I pull it to try a new plug. I tried 4 new plugs still won't start it wants to u can hear it wants to but won't. any ideas? should I try shooting starting fluid in air box? I have choke on while tryin to start or choke off from re assembly. thanks man
Sounds like it is flooded. Drain carb of fuel, remove plug, and kick it over with rag over plug hole to clear fuel. You may want to even let it sit for a day to dry out.
@@HTMR yep! thats exactly what I did and it fired right up! I'm 2 out on air 3 out on idle still stock. waiting on my v force 3s and jets now to come on
i have a '94 kx250 and i cant figure the carb out. what should i do if the idle is too low and the bolt which you tune idling with doesnt raise or decrease the RPMs?
Hello I have a 250 kx 99 and the cdi her and the dense 071000-1440, he ten two connectors and small spare two pins of the connector cdi unused, I wonder if you know what good would these two pins cdi, I would derepente find out if one of them were a traction control or limiter rpm or some other function, wait thanks.
I was under the impression that the screw above the pilot air screw was the throttle stop screw. I thought you tuned the idle with the pilot air screw. What does the throttle stop screw actually do then?
what part is that exactly called at 2:06 those 2 connectors cuz i flipped over on my bike and one is torn off would that make the bike not start also ? thanks
+MatthewMCRepair on last question would you happen to know the model# of the carb or model of carb. My father and I are looking for a repair kit for the carb I have
hey i just removed my carb on my kx250 and i forgot were the orange lines go,,,i know where a few go but is there any diagram where they connect so im sure where they go???
Hey thanks for the great how to. I too have a 2001 KX 250. Mine is bone stock. I'm having the same splooge issue that you touched on. I cleaned the carb like you did. The bike runs great. But the black oily sludge is still there. Any suggestions? Also everything is stock settings in the carb with the jets and clip position.
Hey awesome video man, just subscribed. idk if you're still responding to comments or not.. but I recently purchased a kx125 and the guy had quiet a bit of after market products for racing track. But he was telling me he was jetted for track and may run a little too rich for trails (what I do mostly). He was saying it will ride fine and I will probably leave it as is but how often should I take the carb apart and clean it all? And other tips from you would be appreciated
Got an 01 kx250.. it’s sat for years.. currently started working on it and I’m ready to throw the whole damn thing off a cliff 🤣 I thought my R6 was a bitch to work on.. naaaa.. thanks for the vid though maybe I can get mine running now
hey man i have an 07 kx, and after a hard days ride even when fuel is turned off fuel still seems to come out of the overflow tube, and ideas on what it could be?
You need to clean, adjust, or replace the float needle. With petcock off, does leaking eventually stop? Remove fuel line from carb and see if fuel leaks with petcock in off position. If it leaks, replace it.
Hi Matt, I recently bought a 01 KX 250 in very good condition. The bike sounds like its leaning out at 3/4 to full throttle because it sounds like it's running out of gas? It's fine at low to mid range. I run 35 to 1 ratio. Also when I engage & disengage the clutch lever in neutral idling, I hear like a worn bearing noise or something in the clutch. I don't know if this is norm for the KX's? Love your vids keep up the good work mate!
every kx ive had sounds like its going fall apart, my 00kx250 my 02 kx250 and my 84 tecate make so much noise at idle and all have looked great internally during rebuild.
+MatthewMCRepair on your carb when it's still attached to the bike, the black wiring on the carb what is it supposed to do (the black wiring at the top not the throttle but on the side) you disconnect it at 2:52.
Fuel cut solenoid for overrev. The carb is jetted richer for better throttle response. At a certain RPM, the fuel cut solenoid will lean it out so it can overrev better.
MatthewMCRepair yes the previous owner was the one who did that then. Throughout the time of fixing this bike we've seen a welds broken the spark plug wasn't even in. The gas tank isn't even connected the boot two the carb is cracked and the air boot(not sure if it's called that) has a pvc pipe in it. Basically the bike is "mickey moused" together
hey I was taking apart my carb and the floater pin came out my flot fell out with two white spacer things but I have no idea where they go can you help me where they go thanx.
down one size on the main jet and up one position in the needle? chaparral is telling me to do 2 jet sizes richer on the Pilot and Main jets and lower the clip position on the jet needle one notch, assuming it is in the middle stock location. im confussed! i run my bike at 32:1 oil ratio. its a 2000 kx 250. what are your sugestions? im afraid of running it too lean and having problems in the future because ive got the reeds you have and a full fmf exhaust system. also an uni filter if it makes a difference. id just like to know what would be the correct way to tune it.
Aaron Baer Aaron, I have a 2001, not sure what year you have? I live in Chicago (700' above sea level, 60-80°F, and 50+% humidity. The bike is pig rich from the factory. Ask chaparral if they are referencing team green specs, which are too rich IMHO. I ended up with 2 sizes smaller pilot, 1.25 turns out on air screw, next leaner needle on 2nd clip position, and one smaller main. I have a PC pipe/silencer and Vforce3 reeds. The plug really looks clean and it runs crisp. I could go leaner if I wanted too.
I don't have any info on what those marks mean. You might want to contact these guys since they do porting/replating and would know this info: www.forwardmotion.com.mx/ Matt
@@HTMR hi Matthew. I have a yz 250 witj the same carb. My solanoid wire has been chopped by previous owner. Do u highly recommend me getting a new solanoid
If I'm not mistake the carb on your bike is the same as on my 99 kx250? Have you done a video on jetting and setting idle on this bike? Once my bike warms up it seems to ramp or surge a little on idle. I'm thinking the pilot jet is too lean and need to change it or does it just need adjusting? This will be my first time tinkering with it so any help would be great. I purchased it not long ago so I'm not aware of what jets are in it or needle clip position.
+MK116Alex Alex, actually they are rich from the factory. Please email me here: www.howtomotorcyclerepair.com/contact/ I'll help you with jetting. Please include all modifications that your bike has (pipe, reeds, etc..) Mine was really rich and leaned it out some, now it is crisp and more responsive, also the plug cleaned up nicely.
Oh, ok I thought for sure that it may be lean. It seems like it bogs just a little when taking off in first but other than that it runs pretty good and pulls throughout the gears. I'll email you as soon as I find out what jets are on it. Everything else is stock I'm sure.
I got A 2002 kx 250, it’s pretty stock as far as I can tell and there is spooge coming out the exhaust and it fouls plugs like crazy. The jets are 52 pilot and 158 main, not sure about the needle clip since I haven’t gotten a chance to look at it yet. I ride around 1,000 feet. What would you recommend I do to it? Thanks🙃
I have a 250 4 stroke an just up an stopped running, I cleaned the carb an went through it an nothing seemed to be wrong. also checked the spark. Idk what else could be wrong?
pretty sure my carb on my 03 is the same. but all i did was replace float bowl gasket and now i have gas coming from the overflow tube. its only overflowing when its running on the stand and when i shut off the motor it stops even if the gas is on. have any ideas what i did or didn't do?
Ryan, you may have tweaked the float and now fuel level is too high in bowl. Take it apart and check the float height. Also, run 5psi through fuel inlet and open close float needle to make sure it is sealing.
i checked float height and it looked spot on. put it back together and started it up and it was fine and i shut it off..15 min later went back and started bike and it was coming out the overflow again. I don't have a air tank to run air through the fuel inlet and how do you open and close the float needle?
I have an extremely important question!!! i finally finished *rebuilding* my 2000 kx 250; however, the thing is, when i start my bike it *revs so freakin HIGH* that i *thought it was going to explode!* i tried to use the kill switch but it didnt work. it revd like it was on *FULL throttle* for like 1 full minute!!!! thank god it fell over and shut off somehow... anyways, do you know what the hell was wrong with it? and i know for sure it wasn't a stuck throttle. Love your kx 250 videos they helped me alot!
It sounds to me like you have an air leak. What happens is the engine draws air in through a leak in the engine which leans out the mixture and causes a runaway engine effect. I would start by pressure checking the engine. More than likely there is a damaged gasket or seal somewhere in the engine and it's drawing air through that. Before you start it again remove the air intake boot and if the engine revs uncontrollably again stuff the intake side of the carb with a rag or your hand which will cut off the air to the engine and stop it. This is a fairly common occurrence with old 2 strokes.
In addition to MotoShan's reply, did you have the choke on? These models rev really high on choke for some reason. I toggle mine off/on several times while running until the motor calms down. Verify that the kill switch works by checking for spark with engine off. Double check the idle adjustment screw and make sure the slide is not hanging UP on something. Let us know what you find.
MotoShaman MatthewMCRepair Thanks guys for the help! The problem was both an air leak and the choke. I original purchased the bike with a blown bottom/top end and i had them *welded up* to reuse them; however, the weld wasn't perfectly straight so *it was leaking* from the crank cases. So all i did was put some *JB weld* on both case half surfaces and pressed them together so it'll dry with an air tight fit. Did a rebuild and now it runs like new! :)
Question, I just bought 1993 KX250 that been sitting for 10 + years , I cleaned the gas tank ,Carb And it won't run at high RPM .What do you think is problem?
+Darrell N It just won't rev good to a high RPM? Have you checked the compression? Feel free to email me here: www.howtomotorcyclerepair.com/contact/ And I can help you out.
Could use some advice my bike is a 01 kx250 pro circuit pipe and I ride from 4,650 feet elevation to 8k elevation my main jet is a 155 and my pilot is a 45 I run 32:1 100 octane fuel mix and my bottom end is horrible I've tried lots of different pilot Jets from 52 down to 38 and all different positions of the needle and the air fuel mixture screw and still my bottom end Boggs out but my top rips any advice?
Stock needle I put a 50 pilot back in it and the needle clip is at the second from the bottom it's a little better but Boggs bad still I wonder if 32:1 is too rich?
Hey Matt one other question I am new still learning jetting my kx 250 has a 152 main is that leaner or richer than a 155 ? My bike has full FMF pipe ported head milled and vforce Reed's and I live in Michigan. Bike runs good just wanna make sure if I should make any changes so I don't hurt the motor I rather it. Run on the richer side if anything. Thanks Matt
Surely you have solve this issue, as this comment is seven years old. That being said, anyone else who may be having the same problem, I would recommend a reverse drillbit. Start in the middle and start drilling. Work your way up, and eventually you will be able to remove the screw. If you’re lucky, the reverse bet will catch a piece of metal and will back to the stripped screw out for you. I have remove many many bolts this way.
So putting the float back into position, do you have to put it in a certain way or can you just put it in the same way you pulled it out without putting it in a certain position?
At 9:35 there's a hump on the body of the carb right by your right thumb. Mine is drilled out and so is the float cover where the two halves join together. The hole drilled out in the carb doesn't go to anything because I can suck on it and it will hold on to my lip due to the vacuum. If that doesn't scare you off continue reading 😁. If I suck on the hole in the float cover I can tell it goes to something but I barely hear the air coming through. Anybody know about this? This is just another mystery wasting hours of my life LOL.
+MatthewMCRepair ok thanks. I have just taken my carb out and I'm not sure how to position the throttle position sensor and the rubber boot/cap is loose on the fuel cut solenoid. how do I align the sensor and is that boot/cap a problem?
+Nop Way I never had to adjust sensor so I can't comment on that. I have the service manuals that you can grab for free, it should walk you through it: www.howtomotorcyclerepair.com/kx125-kx250-oem-service-manual-99-08/
Didn't own one at that time. I have the vessel impacta in p2 and p3 and it is awesome! It has an impact built in. It works pretty good on all but the tightest ones. Here are the links: amzn.to/28LVAsc amzn.to/28LLmqP You will need p2 for this carby.
hey thanks for the links, here is a link to my 96' KX125 im working on www.vitalmx.com/forums/Old-School-Moto,22/1996-KAWASAKI-KX125-find-build,1303364
Cool. You def have your work cut out for you on that project. Should be awesome when done. I have a engine rebuild video if you are interested: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-D5rsBThsVRU.html
yeah, once i get my motor out i will have to get your video, I know V8's better lol, odd question but I noticed on your air blow gun it has a rubber tip that you were using on your carb video, where did you get it? all I seem to find is cheap ones but I would like to get one thats gonna last
My blowgun is a blue point, got it off the snap on truck 15yrs ago and probably paid way too much for it. Here is one I found on amazon: amzn.to/29bfz3p
