excess 2 stroke smoking

[Fakhers15]

hey guys, 

i have a 1998 ktm 250 exc, with a fresh top end on it that smokes a lot more then normal  

ive heard that it could be jetting issues but however ive already jetted the bike back to oem specs and even leaned it out to 50:1 

what could the issue be?

[Doc_d]

 

Bad crank seal allowing gear oil to be sucked in and burned would be my only guess.

Edited June 12, 2017 by Doc_d

[Fakhers15]

Yeah I think that could be it cause my gear box oil was full before I went riding and afterwards it was a lot less 

[BTD123]

Start with the crank seal.

[seer]

 OEM specs on older ktms are typically horrible. Besides it's a starting point for any brand. Adjust as needed.