[trailrider]

My son started out on a -04 KX 85 and since has moved up to a fourstroke KX 250 but will occasionally jump on the 85 to ride in the yard.The problem is last time he was going to ride the 85, he checked the fluids and the coolant was very low and the crankcase oil was milky.The bike will still crank and runs decent so its not totally cooked.Am planning on doing topend complete rebuild but what about the bottom?Crank rod and bearing all seem fine and the bike has never been raced or riden very hard.Just wanted ideas before I order parts.Any feedback woud be greatly appreciated.
trailrider

 

[kx85]

Just do your regular tune up job.
Change oil an fluids on bike.
You don't have to rebuild the top end until its blow 120 psi compression

 

[hubz14]

Milky bottom and low coolant level seems like contamination. Might be a head gasket leak so tear it down anyway. Clean the carb in straight vinegar if it's been sitting and is hard to start or won't idle. Leave the rubber alone. It won't swell like chem-dip or the more industrial strength carb cleaners.

Drain the crankcase and wash it out with kerosine and fresh oil. Then dump the mix and change to your regular oil on your rebuilt road test around the backyard.