Howdy! A friend bought this Bruin new last fall and has had problems with gear oil frothing/foaming out of the vent tube and dripping on the exhaust. He re-routed the hose(now clear to see better), and has lowered the diff level by about 3/8" from the fill hole. It's still coming up about 6 inches in the tube, but not all the way out like before. It seems to be worse when riding hard in lower gears, like climbing steep inclines. Running up the road in high gear did not produce the same results. Several calls the his dealer has gotten him nothing more than "ignore it". He has several riding buddies with ATVs and none of them have the same problems. Anyone seen or heard of this before? Any help would be appreciated.

Tim

 

I have the same issue with a 450 kodiak. It seems to be a yamaha 'feature'.
For now, my latest 'fix', is i went to the suzuki dealer, and bought the rubber bellows, that they use on their differentials. Its a totally closed system now, and when it expands the bellows gets bigger, but when it cools off, the bellows shrinks back, and the fluid stays in the diff, and not all over the motor.
He could try that.

 

Thanks a bunch Honda Buster! That's exactly what he needs to rectify the problem. I'll pass on the info to him.

Sincerely,

Tim