2004 CR250 engine sound.

[JDubya381]

Hey all, I noticed a peculiar vibrating/shearing sound when the engine idles down. It's sort of a "wuuunngg *gjggj* brbrbrbrbr" sound (if that makes any sense).

I've heard about the noisy crank noise that was topic of discussion in the original magazine reviews of the 3rd gen CRs, and I've also read about the tin foil crank coating shedding on the 02-04 models. It sounds like it could be either of those two options, a ring that is moving irregularly or a clutch plate that broke. It's just odd because I don't hear it any other time than when the idle drops back down. I

did switch from Bel Ray H1R to Maxima 927 recently, as well as moved the clip to the second spot from the top on the JD red needle, which saw dramatic performance increases across the entire throttle range.

I'm starting this thread because I want to know if any others have some experience or insight that can rule out a few of the possibilities or point me in the right direction. I've been a little busy/preoccupied so I haven't pulled any covers off or anything thus far. It still runs strong, but the noise makes me feel as though I'm playing with fire.

All components are relatively new except for the bottom end.

[RippinCR250]

I'm not sure if I'm sounding it right!! Haha wung gjgjgj brbrbr. Wung gjgjgj brbrbr......how do u sound it out??

[wykyd450r]

I'm not sure if I'm sounding it right!! Haha wung gjgjgj brbrbr. Wung gjgjgj brbrbr......how do u sound it out??

 

 

Dont matter how it sounds lol....The looks of this bike screams bad ass!!

[JDubya381]

Lol I know that was ridiculous, just trying to give you an idea thru my keyboard. The noise only happens in a very specific range of revs, just a bit off idle.

[RippinCR250]

Can u post a vid?

[JDubya381]

Can u post a vid?

Yeah I think I can get my phone to do it. It's pretty audible, so hopefully it'll pick it up. I'm gonna pull each covet off, as well as the exhaust and take a quick peak inside the cylinder.

Like I said, I made a step in a leaner direction and switched premix. Same 32:1 ratio tho.

[choppertown]

that sound is a leaking left main seal. or a gasket(base or center case) but i put my money on the left hand crank seal.

[JDubya381]

that sound is a leaking left main seal. or a gasket(base or center case) but i put my money on the left hand crank seal.

What makes you say that? The left hand seal is new and has only a few rides on it, had it replaced by a shop. When I pull my clutch in (bike shut off) I can hear what sounds like a clink or a leak. I think my actual right side case is not holding up

[choppertown]

when i sounded out what you put as the sound, it sounds like the bike is surging and pre-detenating. 2 conditions of an air leak.

[JDubya381]

when i sounded out what you put as the sound, it sounds like the bike is surging and pre-detenating. 2 conditions of an air leak.

Hmm, okay. Well I'll consider that too.