Another Question???????? Crank Seals

[windowscleaning]

Just wondering, if you know your crank seal(s) are leaking, is there anyway to determine which one it is, or do you have to replace the both of them? In a kx 125...Thanks for your help in advance...Jason

 

[AV8R]

If you are burning transmission oil it is the clutchside crank seal. If inconsistant idle, or big unexplained bog in the absence of any other changes, or noted stain behind the flywheel then it is the flywheel side seal.
You can also conduct a leak down test and see where the air is leaking out by spraying soapy water on the flywheel side or noting air coming out of the tans vent tube for the clutch side seal.

 

[windowscleaning]

Well I am up to this point: I have removed the top end and noticed a little black oil rubbed on and around the piston. I did not notice any mass of oil or black residue on the bottom or around the crank. Is it normal for the black oil, possible the 2 stroke mixture to be seen on the piston, and not in the case/crank?

 

[windowscleaning]

I gotta say........Bikebandit.com ROCKS!!! I spoke with a live rep.online and he was able to give me all the information I needed!! If anyone knows anyone from there his name was Shane. Thanks for your responces but I got it figured out now.....Also wanna give a special thanks to Lucky (LCS racing) for all the help he has provided. If anyone has any service needs either one of these places can help and are very, very, friendly about it all...Take care and hope to see you all on the track soon!

 

[whizzit]

So what was the outcome, which seal was blown?

 

[windowscleaning]

It was the clutch side seal, but come to find out there was a 98 piston in a 96 motor thats been bored to 80 over.