[SpudRider]

Originally Posted by detours

...I noticed Joe said it could happen if you overfill the oil. I'll recheck the level with the proper procedure, but I sincerely doubt that's the issue unless the 1.7L spec is wrong. I carefully measured 1.7L (not quarts) of refill oil after completely draining from the plug and all 3 filter holes. I know some oil remains, but not much if you drain it warm and tilt the bike both ways, so I really doubt that's it.

If you severely overfill the oil, the excess oil will definitely come out the crankcase vent, and collect in the down tube. However, overfilling the oil will not cause fuel to collect in the down tube.

The specification is 1.7 quarts, not liters. I fill my engine with 1.7 quarts, which is 1 quart, plus 22 ounces. This amount of oil fills the sight glass perfectly when you measure the oil level using the proper method.