coolant foam question

[CTV_Paton]

I am looking into buying a 1997 yz125, it needs a top end soon but I noticed the coolant froths a bit under throttle and goes away like carbonation when idling... no discoloration it's a still clear red, and no obvious bubbles in the pumped water when revved... Is that quarter inch layer of bubbles an issue? Or will a new piston kit and gaskets cure it anyhow?

Edited July 12, 2011 by CTV_Paton

[William1]

Sounds like a leaking head.

You say in one part that when you rev, it foams up anthen in the next breath, it does not.

But it sounds like the bike needs work.

[CTV_Paton]

yea when its revved the fluid flows clear, when you let off the throttle and the rpm's drop the fluid settles at the full level with a layer of foamy bubbles on top, and within some seconds the bubbles vanish. like shaking a bottle of pop only you see no bubbles until you stop shaking and there's none being purged with the cap still on.

[Greg Y]

could be a leaky head gasket, or as serious as a cracked jug (rare).