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CRF 250R Running Rough

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I'm stuck, and can use some help. Son's 250R was running kind of rough last time we rode, but I thought it was due to a top end going since I shimmed it a couple times. I replaced the top end, and also put in a new piston....and the bike won't start. Got it running by pushing it, and it was running pretty rough. Thought it might be a dirty carb....so I took the bike apart, and thoroughly cleaned out the carb. The bowl of the carb was good, but the top end where you put in the needle had some slimy mud probably from pressure washing. Cleaned it thoroughly....put the bike back together, and still running rough. I can push start it to get it going but it wont idle without continually hitting the throttle. If it stops, it won't kick start. I do have a new spark plug in there also...the air filter is clean. Could it be the CDI module or the spark plug connector assembly? I double checked the timing, and I know the shims are right on. It does have good compression, so I know the piston is in there right, and when I can get it going it will pull normally. I don't know what to check next. Thanks for any help!!! :excuseme:

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I would double check the valve clearances again... Just to be sure..

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Check and make sure the carburetor is all the way in the intake boot and the clamp is tight. Also make sure the intake boot is all the way on the head and the clamp is tight. Make sure the ground wire at the ignition coil is tight too.

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Thanks......forgot to mention this is a 2007 model. I was reading through the manual last night, and saw that I forgot to pull the leak jet out. So...I took everything all apart....again.....and really went through the lower section of the carb. The leak jet looked a little clogged....but now I think it was just gas in there. I put the bike back together.....no luck. I made sure the seals between the carb and air box are tight and in the right alignment. Then I pulled the tank and pulled the spark plug coil to measure the resistance. It apears to be OK. My meter doesn't go that low. I pulled the plug and did the spark test against the engine case. There is spark on every kick. My son's friend has a 250R....so maybe I can switch the CDI and plug coil. Anyone know what are the symptoms if the stator is bad? Thanks for any help.....don't really want to put this in the shop!!

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did you check to make sure that the plate on the carb slide isnt upside down? this is very common to do and it makes the bike not idle but still will run fine when you push start it

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Guess I don't know what plate you are talking about. The one on the top of the carb held in by 2 hex screws?

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Answer to the question above about checking the ground wire. Are you talking about the ground wire I see it behind the right radiator.....green wire? It's attached properly. I checked to see if maybe the wire was loose or broken....but it looks good. Is there another ground wire I need to be looking at?

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Since your pulling everything apart, pull the oil filter and see if there's any metal in it.

What barnhillmods is talking about in terms of the plate in the carb, there's a plate that sits on the throttle slide. If you pulled the top 2 screws out and removed the slide where the needle is located, there's a plate that sits on the slide with a very delicate seal on it. 2 things happen with this. You could have installed it upside down. The hole in the plate should be at the bottom. You can usually see which way it goes in by the carbon stain where the hole used to be on the slide itself. That is the most common issue. The other is the plate seal has a tendancy to get damaged by carb cleaner or any other kind of cleaning solvent. Same results either way.

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I'm stuck, and can use some help. Son's 250R was running kind of rough last time we rode, but I thought it was due to a top end going since I shimmed it a couple times. I replaced the top end, and also put in a new piston....and the bike won't start. Got it running by pushing it, and it was running pretty rough. Thought it might be a dirty carb....so I took the bike apart, and thoroughly cleaned out the carb. The bowl of the carb was good, but the top end where you put in the needle had some slimy mud probably from pressure washing. Cleaned it thoroughly....put the bike back together, and still running rough. I can push start it to get it going but it wont idle without continually hitting the throttle. If it stops, it won't kick start. I do have a new spark plug in there also...the air filter is clean. Could it be the CDI module or the spark plug connector assembly? I double checked the timing, and I know the shims are right on. It does have good compression, so I know the piston is in there right, and when I can get it going it will pull normally. I don't know what to check next. Thanks for any help!!! :excuseme:

Did you make sure to release the tension off the cam chain via the auto-tensioner?

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My cam tensioner does not have a lock on it. I just put a screwdriver in there and turn it until the tensioner is all the way in.....then I hold that and install the top and bottom bolts. When I have the bolts in.....I slowly release my screwdriver. I've checked the valves and reshimmed allot, and never had a problem. Will the bike not start if this somehow got broken?

OK....I think I know what the throttle slide is now. On the 2007 model....there is a hex nut that holds the needle. I took that off, and pulled the needle out.....cleaned everthing in there with a Q-tip and alcohol. I basically just pulled on the thottle slide to move it up and down and cleaned in there with alcohol. Then I used compressed air to blow anything out if there was something in there. I took a couple picts so I could rememeber how things go back together if I got "stuck" :excuseme: Looking back at the picts, I see an allen head holding a bracket that is mounted back to the neeedle.......is that what you are talking about? I never took that off......should I go back and take all that apart?

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I'm starting to think I need to pull the carb again. See the picts....I did not clean the throttle valve area. I'm wondering if there is some slime in there. Would that make sense? Holy crap....I think I've taken this bike apart 4 times now in the last couple days!!! If there was some dirt in there, would that keep it from starting? Installing that hot start connector took me 30 minutes last time I took the carb out!!

http://www2.snapfish.com/thumbnailshare/AlbumID=1620808022/a=156142299_156142299/otsc=SHR/otsi=SALBlink/COBRAND_NAME=snapfish/

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I'm starting to think I need to pull the carb again. See the picts....I did not clean the throttle valve area. I'm wondering if there is some slime in there. Would that make sense? Holy crap....I think I've taken this bike apart 4 times now in the last couple days!!! If there was some dirt in there, would that keep it from starting? Installing that hot start connector took me 30 minutes last time I took the carb out!!

http://www2.snapfish.com/thumbnailshare/AlbumID=1620808022/a=156142299_156142299/otsc=SHR/otsi=SALBlink/COBRAND_NAME=snapfish/

Hey DJ250X stop jacking with the carb, It ran fine before you rebuilt the top end and nothing was wrong with the carb then right? So its some thing you didnt do right on the rebuild.........I would lay money on you have the cam chain off by a tooth or two. Especially if you can push start but no kick start, This is a classic sign of valves being opened premature in the start sequence. However with the push start you can build enough pressure to allow fire.

reverify that the the cam and chain and every thing is all lined up. Once you do get it started you need to keep and eye and ear on it for possible damage done by starting it while not lined up properly.

I have rebuilt my 07 3 times now and it allllllways starts on the 3rd kick--worst case!!!

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Welll.....since I had some time tonight.....decided to pull the whole thing apart again. Actually....I'm getting fast at it now! Got it all apart and now I know where the throttle slide is....and how to take it apart. But.....the Japs put in a pinned torx screw on it.......who the heck uses that? Have to make a trip to the h/w store tomorrow to see if I can find one. By the way....the first picture is before I cleaned the carb.....last one is after. Not sure if this is the problem....but I've got to eliminate all carb problems first.

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I checked the timing a couple times already, but I can check it again. This is the weird part....his bike had a bad intake valve....so I was shimming to keep it going. Usually....we got about 3 rides before I had to reshim. I was planning on replacing the top end with new intake berylium copper seats, so I wasn't worried about running it down. I finally ran out of shim sizes....so I new we only had a couple runs left before I sent the head off. On the second ride....the bike started running rough...so we cut the ride short. I thought it was the valves going bad.....but now that I have it all together again.....I can't get it going. That's why I keep picking on the carb. If it was running good before the top end.....I would definately be looking in that direction. I will the timing again though.

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Welll.....since I had some time tonight.....decided to pull the whole thing apart again. Actually....I'm getting fast at it now! Got it all apart and now I know where the throttle slide is....and how to take it apart. But.....the Japs put in a pinned torx screw on it.......who the heck uses that? Have to make a trip to the h/w store tomorrow to see if I can find one. By the way....the first picture is before I cleaned the carb.....last one is after. Not sure if this is the problem....but I've got to eliminate all carb problems first.

yeah that stupid security hex got me to, I picked up a set at Autozone.

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I checked the timing a couple times already, but I can check it again. This is the weird part....his bike had a bad intake valve....so I was shimming to keep it going. Usually....we got about 3 rides before I had to reshim. I was planning on replacing the top end with new intake berylium copper seats, so I wasn't worried about running it down. I finally ran out of shim sizes....so I new we only had a couple runs left before I sent the head off. On the second ride....the bike started running rough...so we cut the ride short. I thought it was the valves going bad.....but now that I have it all together again.....I can't get it going. That's why I keep picking on the carb. If it was running good before the top end.....I would definately be looking in that direction. I will the timing again though.

I checked my timeing 3 times and found on the 4th that I was off a tooth. It is really that simple to get it off. I would place money on it at this point. You did replace the valves and have the seats cut also right?

I am sure you know to make sure you are on the proper stroke. ie make sure the exhaust rocker is loose, then line up the tick mark in the transmission. Leave the allen wrench in the engine as you are messing with all the other things as this will help you quickly reference any movement.

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Ok...thanks for all the help. I'm going to Autozone tomorrow, get the right socket....clean up the carb....then recheck the timing. I'm hoping the timing is off 1 tooth. I'll let you know tomorrow. Thanks again!!

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This same thing happend to me, after alot of kicking it stated running, after a hour of running the intake side of the cylinder completely melted/ sheared away and the piston exploded on that side. Bye Bye brand new pro circuit engine....

anyways, I doubt thats the case, I just had to say something since its the same symptoms.

I would step away from the carburetor, that cant be the issue, Unless you had it off while you had the valves done. I agree with everybody else....timing timing timing.

EDIT: check your TPS while the carb is off...

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Well......you were right....it was the timing.!!! I went back in there last night and moved it 1 tooth. I originally marked the chain with a black sharpie, but when I did the rebuild top end and new piston, I thought maybe the chain slipped a link. Guess it didn't. Started up 2nd kick!! At least now I know I have a clean carb!! I'm going to run it a little bit and change the oil and filter to make sure I didn't screw anything up running it some with the timing off. Valve clearance was right on last night when I pulled it apart. Thanks for all the help!!!

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ok in the future...once the cam comes out black sharpie marks really go to the way side for importance. Its the tick mark inside the trans+the two marks on the cam shaft all being lined back up.....You can do what ever you want with the cam chain at that point.

Didnt we bet some money on that timeing thing??? LOL keep an eye on it for the first ride. Listen to it, Lack of HP stuff like that might indicate a piston got hit by a vavle.

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