01 KX 250 Rebuild?

[scottylook]

Ok I am going to try to explain this. I've had the bike for about 2 months. It's so dry out here I have only rode it a hadful of times. I took the pipe that was on it off and put the stock one back on cause I am learning and didn't want to beat the crap out of my Pro Curcuit Pipe. Seemed to run a little better with the old pipe on like they hadn't jetted it for the new pipe. Well anyways. I took it over to the dunes and rode it over there. First day no probs, second day no probs till I rode it down to the ocean. I didn't run it hard down there just down to the beach and back but not hard. On the way back I could tell there was a weird noise. On throttle no real noise, but let off and the noise starts. So you rap it out and sounds ok, but let off and you get the noise. If you hold the throttle in one spot kinda low you can hear it to. There is still all the power but it seems to run kinda fat. I took off the seat and checked the air filter and I can't see how there was any air getting through that. I thought it could be the pipe so we put the Pro Curcuit back on and its still there, maybe a bit worse. Started 2nd kick though. Any ideas. I know the bike has never had the top end done and the kid I bought it from rode it allot I think, never raced though. Thanks for any help. I will be tearing it down tonight to get the lowdown on how it looks but was hoping someone could give me some ideas.

Scotty

 

[GhostRider32]

Are you saying that you can't see how any air could get through the air filter? If it's that dirty, clean it before you tear it down.

 

[scottylook]

Would not enough air cause that noise? Sounds interenal????

 

[GhostRider32]

It probably wouldn't cause an internal noise but start with the obvious first. Even if you do have an actual engine problem, if the filter is so dirty it's letting dirt by then once you rebuild, you'll have another problem soon from dirt in the engine.

 

[Studboy]

Check your bigend rod bearing. That's similar to what mine sounded like before it went. Does not idle as well as it was before?

 

[uts]

I'm with studboy. Sounds like your big end bearing. Hopefully for you it is not. Good luck

 

[scottylook]

Thanks guys. Tore it open last night. Wrist Pin Bearing is done. Looks like I'm just going to put a whole new topend in it. Looking at stuff right now. How are the pro lite pistons? I think that's what I am going with. Let me know. Thanks

Scotty

 

[Studboy]

Wow, it's rare that a wrist pin bearing goes. How long has it been in there? I wonder if there is something else at work.

 

[scottylook]

Well its been in there since 01. This bike has never had a new top end put in it. Everything else looked good as far as I can tell.

 

[Dragmeistr]

Sounds to me like you might have been lean with the extra load of the sand on your bike. I ride in the dunes quite a bit and I had to jet my bike extra fat to keep it from knocking on pump gas. Once I switched to a decent gas, I typically just move one up on the main and raise my needle one clip. I am far from doubting your abilities to diagnose your bearing, but are you sure it just wasn't a lean knock?

 

[scottylook]

Well the wrist pin bearing has tons of slop in it and the rings are toast. I don't think it was lean cause it was running pretty fat over there, spoogey. I rode it for 2 days on the same gas and then that happend, so I'm not sure. Could be gas, but there were problems for sure in there.