Jetting or Crank seal?

[VTNewb]

Hey guys,
I picked up a relatively mint 1996 KTM 250EXC. It was smoking quite a bit. I ran about two tanks of 40:1 (bel-ray) and cleaned and re-oiled the air filter. After a 30 minute ride I have a big nearly 1 inch slick of black spooge out the silencer. Now the questions. Is my crank seal leaking and sucking in some minimal tranny fluid, or is my jetting just wacky. I've never done a leak down test before, but I hear this is what it's for. Ideas?

 

[RM_guy]

It could be either. I'd suggest doing the leak down test since the bike is new to you. There could be other problems that you just haven't seen yet. You could chase the jetting but spend tons of time before you decide to go ahead and do the leak down test.

If there is a leak you will need drain the oil and pull off the right side case so you can see the seal. Also pull the magneto cover so you can see the left side seal. Spray soapy water on the seals to see which one is leaking.

 

[Coop]

What's the plug look like?