Help with 00 cr250

[Huck1]

Help Please 00 cr250

Ok here is the problem, after my last ride I can not rev my bike without bog. Air filter is clean, new spark plug, silencer clear, low hours on top end<-- or so I am told, checked leftside cover-- turns 90 at higher r's but if you nail it, it just sounds like its gonna die. I asked a friend he said he thought maybe a stuck power valve, but if its turning 90 freely how can that be? Could it be the reeds, or carb problem? I do not know much on bike maintence yet, but do change oil, clean filters, wash every ride, ect. please please please! My life doesnt depend on it but dang does is suck :bang:

 

[Huck1]

help anyone???

 

[tx246]

has the weather changed drasticaly since you have last ridden it? temps can cause that sort of problem. i assume you are talking about opening the throttle right off idle? if that is the case, first check the air screw and make sure you are 1 1/2 to 2 turns out from all the way in at max. you might have a clogged idle(slow) jet. its the small jet that controls off idle to 1/4 turn of the throttle. it is largely responsible for throttle response. if it has gotten a lot colder from the last time you rode it, you might have to richen it up one size.

 

[Huck1]

actually, I rode it in very much the same weather last. Its actually when held 3/4 to full throttle, if held wide-open it just burps and studders.But it has been colder in general!

 

[mobrown]

Check your compression

Sounds to me like you have a compression leak somewhere most likely the top end. Compression should probably be around 170 psi or so. Could be that the head and/or base nuts may not have been torqued correctly during top end rebuild.

BTW what do you mean when you said it "turned 90"?

 

[Huck1]

Sorry, I was refereing to the check cover removed on left side, little shaft turns 90 degrees when revved, the exaust valve, i think, Its what the manual said to check.

 

[Shad 250]

Sounds like the power valve is working properly. Something that has not been mentioned is the possibility of a crank seal going bad. This is not so easy to check without a leak down test. I also have a 00 CR 250, and I am planning a bottom end rebuild this winter, since I am pretty sure it has never been done. Anyhow, if the left (stator) side crank seal starts to go bad, it can give a lean condition, causing the bog you describe. I'm not saying this is definitely your problem, but surely worth looking into, as it can end in catastrophic engine failure if not fixed promptly!

 

[Huck1]

Looks like it maybe the crank seal, its the only thing we found.
reeds good, carb good, baffle clear, ignition good, main seal leaking!

thankyou all, and we will see if that fixs it!