Motorcycle Repair: 1985 Yamaha Maxim 750, vent tube, engine flush


Question
Hi  There, not sure if this question got through earlier, my apologies if it did.My buddy has a "85 Yamaha Maxim 750. The problem is the oil keeps getting " malted milk" looking, very thick and light brown in color. We've tried 3 oil changes to flush system,keeps coming back pretty much right away.Water levels havent budged, bike hasn't sat for any period of time.I found a slight bit of condensation and milky thick oil in vent tube to air cleaner.It looks like this milky oil is throughout engine as I can see it through the sight glass and inside crankcase through the oil filler hole. Any help would be great !
Thank you for your time, Al

Answer
Hi Al.

Doing the oil changes will not get rid of the problem.  The engine needs an engine flush.  You can get the stuff you need at any decent auto parts store.

 Do it right and there will be no more fungus in the engine.  Yes, I said fungus.
 That milky white stuff is just that.  When water mixes with engine oil and stays a while, then fungus grows and that is what your friend has in his engine.  Doing a proper engine flush will eliminate the problem.  You may also want to find out how and why water is getting into his engine.  As far as water levels, I don't recall the Maxim being a liquid cooled machine.  I had a 750 Midnight Maxim and it was air/oil cooled, so I am not sure what water levels you are talking about.

Anyway, do the engine flush and all should be well.

Good luck and ride safe.
FALCON