02 KX250 Spittin black

[socalcajun]

My rear fender after each lap ridng last Saturday. It would not get into the band in any gear. It just bogged its way around. Bike starts but smokes lke crazy. Well way more than a 2 stroke should. I have been advised that its my crank seal. Honestly I can't dispute that one bit sounds about right for what I was experiencing.

Put your thinking caps on smoker heads. Any input will be appreciated.

Thanks,

Dan

[Coop]

Did you lose transmission oil? Drain it and see. If it's smoking that much and puking that much oil, if it's the crank seal your transmission oil will be greatly diminished. If not check your compression.

[TMKIWI]

Yep, that fender looks pretty black.
Check your gearbox level.
The latter kx's have a sight glass for the gearbox.
I take it you havnt changed the fuel mixture at all.
Could well be the crank seal.
Remove your right hand case and have a look.
You will need to remove the clutch and crank drive gear. Replace the seal behind the crank gear.

[Coop]

Yep, that fender looks pretty black.
Check your gearbox level.
The latter kx's have a sight glass for the gearbox.
I take it you havnt changed the fuel mixture at all.
Could well be the crank seal.
Remove your right hand case and have a look.
You will need to remove the clutch and crank drive gear. Replace the seal behind the crank gear.

Unless the new models had a case change, on KX's you have to split the cases to change that seal. KX's have a lip and the seal installs from the inside of the case.

[TMKIWI]

You well may be right  
I was actually meaning just to check.

[Coop]

You well may be right  
I was actually meaning just to check.

I thought maybe you were, but wanted to clarify so socal was aware  . I have owned and worked on a lot of KX's and I think that lip is a ridiculous design.

[socalcajun]

Yeah crank case oil level went down.  Pretty good indicator of the seal then.  It's been a long time since I've wrenched like this. Guess I was in a bit of denile.  Let the fun begin. Thankfully it's a 2 stroke.

Thanks coop and tm. I appreciate your responses.

[Coop]

Might as replace both crank seals and check and/or replace the crank bearings while you have it all apart. Probably a good idea to measure the piston and bore too and at least throw some new rings in for cheap insurance.

[socalcajun]

Yeah coop that's solid advise.  Already have the list made out. Starting at the bottom and working my way up.

[scotty dog]

Gee thats no good cajun, thats gonna cost ya some ridin time, cant have that now...
I'd replace all the tranny bearings and seals too, put a new ring in and pull the powervalve to bits and give er a good scrub up too while ya there

[Coop]

...pull the powervalve to bits and give er a good scrub up too while ya there

Dangit, I knew I forgot to suggest something! 

[socalcajun]

You bet the power valve is on the list.  Checked it the day of and it was as black with oil as the ace of spades.
Carb cleaner pretty good for that purpose?

[scotty dog]

Yep carbie cleaner and a little wire brush ya get from ya local hardware store, they bout the size of a tooth brush. Good luck bro.

[socalcajun]

Well I have a turn on this story. I found a wrench of great reputation to crack my cases and replace the seals for 175 plus the cost of the seals. Not bad I think, so instead of me tearing into it for 6 months then maybe having to take it to have it put back together I'm going to have this cat to do it. Oh yeah since he has to tear it down anyway he'll replace my top end for the cost of the parts. I'l be riding again in no time.

[TMKIWI]

Good job.
If your not comfortable doing it your self thats a cheap price to then know it will be done right.
Get it done and get out there riding