CRAP water in gearbox gt750j

[kiwi]

hi guys,
just drained gearbox and oil looks a bit milky looking,i dont seem to be using any water but dont know how much it would take to do this,how would this get in there ,and would i be doing any real damage if i changed oil ,often as dont really want to rebuild engine yet,
dennis

[re5rotary]

Hi it doesn't take much water to start to turn the oil milky. I guess it could be getting in through the water pump although the water should come out the 'tell tail' rather than go in the gearbox. The other worse option on a J is the waterway that runs between the cases can leak. There was an oring in this area on later models presumably as this was a weakness on the J. The motor has to come apart to fix this Im afraid regards Terry

[Vintageman]

Radiator stop leak might be worth a try?

[pull the wire]

Under the oil pump cover there is a vent for the transmission next to the oil pump. Wet weather riding or too much water during wash time could allow water get in there. I had a GT750 long ago that snapped one of the top engine case 6mm fasteners and water got in the trans. I think it was bolt #25 under the starter.

I hope this helps

[oldjapanesebikes]

Additional to the other earlier comment - J's and some early K's are famous for this type of failure due to a design flaw. The water bypass was re-designed with the mating surfaces made wider in the upper and lower crankcase castings and the addition of an o-ring at around engine 36198.