Oh No! Milky Oil

[Relsom]

This '90 200 has been sitting for the better part of the last 2 years exept for an occasional quick ride to make sure it still works. This weekend I noticed that the gearbox oil was milky. I immediately changed it but it is still being contaminated, either by leftovers or a continuing problem. It starts and runs great, by the way. No problems shifting. A good ride. The volume in the sight glass is normal. I would like to hope that the water pump seal is bad but I'm sure there could be other, more serious or likely causes like a head gasket or worse. What steps should be taken to identify the cause and could the oil just turn thin and milky from age and the gearbox just needs to be flushed out better before refilling?
thanks, .......Chris

 

[ericf7]

i had the same problem with a kx125. it was the water pump gasket. i would start there, flush oil and test run

 

[David Trustrum]

Head gasket will not be the problem. If it was pressurising the system it would blow water past the rad cap first.

Quite common on high mileage kdx & easy/cheap to fix. Pull the sidecover off & inspect the seal & the shaft it runs on. Replace.

Flush out gearbox with some kero so you don’t contaminate the next lot of oil & check the vent tube inlet isn’t going to let water in when you cross a stream.

 

[KDXFreestyle]

yes, Milky oil means that you have some kind of a leak that has to do wiht the anti freeze. When the anti freeze gets into the oil, it turns milky.

 

[jdbrusch]

You can flush out the tranny with a 50/50 mix of paint thinner and engine oil, just install the mix and let the bike idle to warm it up then drain it ,then install some regular tranny oil and ride it for awhile to warm it up again then drain it again,this should get any water out if it is just from condensation.Refill it once more and if the oil turns milky again then the pump seal is most likely the problem,You might be able to get a shop to pressure test the cooling system for you.This was a common problem on the 89-90 kdx and for 91 they installed a second thin back up seal,the second seal will fit in the 89-90 so you can upgrade,check the water pump shaft for grooves and replace the bearings x 2(they can be bought at a bearing shop,part # 608-C3 open no seals)at the same time,they are only a couple of bucks each.

 

[kx_693]

water pump seal is the most likley as everyone else has said.....But you said the bike sits alot, the millky oil could be from condensation, with the weather changes, I had this happen to a motor i rebuilt for someone then it sat in the shop for a year and a half and when the guy finallly came to get it the oil was milky. hope this helps

 

[David Trustrum]

Hope you charged him storeage! 18 months, he should have known he couldn’t afford it, why do people do this? Seen at least one workshop fold for this reason.

 

[kx_693]

He paid for the parts up front, just owed us for the labor.

 

[procircuit21]

i had the same problem on a '91 kdx 200 and all i did was replace the 2 water pump seals and make sure the waterpump shaft is totally smoothe. if there are any scratches on it at all, replace that shaft. they are about 40 bucks

 

[CoryStickney]

Sometimes the oil gets milky just from being in deep water for extended periods.

 

[250RDude]

OK I'll ask a dumb question......................................................................................What side of the seal gets installed towards the waterpump. My KDX was also had the 2% syndrome. The factory manual isnt very specific, just stated "Marked side" towards the transmission. Thanks in advance.