[Chriw Wilder]

I have a 100 inch RevTec with about 1200 miles on it. The motor has a Mikuni 42 on it with breathers from bolts in the head, to the carb with a crossover tube between the headsand carb. The bike has pumped so much oil out the back breather it has chocked out the motor. RevTec tec's said the oil bag was too full so I lower it to about a quart and some change. Still have the problem. The back jug takes most of the bath. It does not do on start up, but rather when it is warm. Thanks for any help.

[CD]

Was this a new build or a replacement engine in an existing bike? Softail? Dyna? FLH? Oil bag on tranny or Softail or something custom?


I almost sounds as if the vent and return hose are crossed. If they are then as the oil is returned to the tank it raises the level to over the normal return tube height which would vent the oil back to the engine and fill the crank case.

The scavenge pump may also be at fault and is easy to test by removing the hose from the oil pump and plug it and put a hose from the pump into a can. Fire it up and run it briefly. You should see a steady return of oil. At or near idle it may tend to pulse but should still flow. Do not run the oil bag dry!