I have a 99 Nightrain I put a new 2 into 1 Vance and Hines and a thunderslide kit in it. Since then I have noticed it smoking when idling maybe because 2 exhausts into 1 could be condensing the problem. It seems to be breathing heavily thru the carby. The other problem I have noticed is the primary drive is always near full of oil and the header tank is low, the last few times I have drained it I have nearly filled a 9 ltr bucket. My thinking is having a pressurised crankcase it is pushing oit thru the crankshaft seal? I have checked the umbrella valves and they are installed and soft( well the front cyl cant get rear off without removing motor off frame) compression test cyl 110psi front 107psi rear leakdown test was 10% with no apparent noises from valves. Does anyone have any ideas as to the cause so I can fault find further as I have run out of fresh ideas?

hi there 94tango i think you are on the right track with the crank seal to primary ,where your oil is going,i would check your crankcase breather hose to make sure its not blocked or squished some how,is it a evo or tc ,make sure the breathers in the heads havnt been blocked of with normal bolts.i am sure other guys will have idears to.welcome to the forum too

Sounds like its leaking through the crank seal.

 1340 EVO last of the good ones lol