Tranny oil getting in the piston

[goodwood]

Help, I think tranny oil is getting in the piston, causing excessive smoke and no power.

What is causing this?  A crank seal?  Which one?  How to replace?

Thanks for you help....it's been a bitch having to ride my 4 stroke 

[goodwood]

Could be coolant also, any ideas?

[scotty dog]

Sounds to me like a crank seal, it really the
only way for oil to get in there,
It would be the
right one but depends if you have to split the cases
What sort of bike is it?

[Coop]

Is your oil level going down? Is your coolant level going down? The answer to those questions we will help make further diagnosis.

[SachsGS]

I've learned over the years to start with the most obvious first and work your way along from there.Have you checked your carb to make sure the bike is not simply running too rich?Left a rag in the air box?(Been there,done that). A leaky trans. side crank seal will have less of an effect on power then,say, a worn needle and seat assembly in your carb.

If your crank seal is leaking grab the flywheel and see if you can detect any play there,crank seals usually start to leak for a reason.  

[xandyx]

Help, I think tranny oil is getting in the piston, causing excessive smoke and no power.

What is causing this?  A crank seal?  Which one?  How to replace?

Thanks for you help....it's been a bitch having to ride my 4 stroke 

sell the thumper and buy a new set of crank seals, and you get 2 problems solved!