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Valve Problems?

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My brother just got a 05 YZ250F used and i think it has valve problems. It refused to start with choke at first, but now it wont even kick start cold at all when i tried. He has only ridden it like 2-3hours since he has had it. I have a 05 CRF250R that ive had since it was basically new and havent had any problems with it. Could it be something else? If it is the valves should we just reshim them? How much would that cost?

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you dont know NEthing tillu tear it down...do comp test...get a sevice manual

check things out...wear...clearences and such and go from there...its too

easy to do instead of just guessing...yz's motors are pretty solid dude to the

5 valve design..its less tansion on the springs...and they are lighter..so u

dont really float valves and such...the hondas had way more problems..esspecially

the first yeear...if you baught it off someone who rode it like a 125 2 stroke

than..it is going to be hurting a lil but...they dont like to be bounced off the rev

limiter 24/7/....you got to shift these things...let me know..

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o ya and tear the carb off...the pilot jet could be clogged if it sat with gas...or

no stabil in the fuel... lata

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Pull the plug, could be flooded. My experience is when its really flooded it feels like it has no compression. Replace the plug and see if it starts. I would find it hard to believe that the valves are out of spec with that low of hours unless it was seriously abused. My 02 has a ton of hours/miles on it and its never had to be adjusted.

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I had a heck of a time getting mine started in the first hours too. Actually, when its jetted well (or in my lazy case, when the conditions are perfect for the way it is now jetted) it starts a lot easier. So that might be it too.

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the compression does seem lower than my CRF.

How can you tell with the autodecompression? :banghead:

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It sounds like that thing has some bigger problems but I would say to replace the plug. When I got hurt my bike sat for a while and after I got enough strength to walk I tried to start it and got nothin. Like the thing wouldn't even burp or burble to show any sign of life no matter how much you kicked it. I put a new plug in and it started on teh first kick, nothing short of amazing. These days I change my plugs like once a month or every few weeks depending on how I am riding.

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My brother just got a 05 YZ250F used and i think it has valve problems. It refused to start with choke at first, but now it wont even kick start cold at all when i tried. He has only ridden it like 2-3hours since he has had it. I have a 05 CRF250R that ive had since it was basically new and havent had any problems with it. Could it be something else? If it is the valves should we just reshim them? How much would that cost?

Most likely not a valve issue. My '05 didn't like to start or run well for a number of the first few rides. Once you break the engin in a bit it should do just fine. Is your jetting good?? Plug?

Its' funny to me that someone would jump right to thinking valve problems on the most reliable of 250F to date :banghead:

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I would say it is probably not valve related. When I first got my 250f it was an absolute BEAR to get started. Once it had some time on it and was properly jetted (the fuel screw has the most impact) it started no problem. Now it starts first or second kick every time.

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well we had a friend's dad who is a mechanic look at it. he said the problem is the vavles opened and will not close from the previous owner riding it like a 2 stroke(high RPMs and pinned). does this sound like it could be it?

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