Possible water damage KX125

[Dirtbike]

Hello,
I asked in another thread yesterday about not having compression on a 1989 KX125 that I am looking at to buy ($300obo).... I think I need to reword my question.

This bike was run into a deep creek (submerged)by it's current owner. He said that it was running just fine before hitting the water. The bike lost its compression as a result and has not run since.

Question: What would cause it to have lost it's compression? I know nothing about liquid cooled two strokes. I've read about reed valves possibly causing problems with compression loss.... any connection?.... Any ideas? The engine kicks over very smoothly just no compression.

Should I steer clear of this bike?

Thanks in advance for any and all help/information,

Again... Thanks,
Dennis

[RichLockyer]

There's a number of things that could have happened... all of them bad.

If it was running when it hit the water and it pulled water into the intake, it likely hydro-locked the piston. Blown head gasket, cracked head/cylinder, broken piston, bent rod...

[Dirtbike]

Thanks for the fast reply and help....

It doesn't feel like it hydro-ed it feels very smooth.... just no compression. I hear no air being sucked in or out when the kick starter is cycled by hand. Could the reed valve cause this as this was mentioned by the owner?

Thanks again,
Dennis

[RichLockyer]

It's possible. If it's broken, there will be no pressure in the case to force air into the chamber, but I really don't think that's the problem. There's still going to be SOME air in the chamber on the upstroke and you should feel that as the piston comes over the top. Won't be much, but you should definitely feel it. If the kickstarter is spinning freely, that sounds bad.

Check/replace the reeds, but if that doesn't do it, you're probably looking at a rebuild.