Frozen rings on K75

[xians421]

I recently purchased a replacement motor from a junkyard. The E-bay description said the engine started and ran before being removed from the wrecked bike. It's been sitting for a few years. Compression check revealed 0 in all three cylinders. Turned it on its side and added some oil into the spark plug holes and got 40 in #1 and 150 in #s 2 and 3. Added some Marvel Mystery oil and waited three days 30 in #1 and 50+ in 2 and 3. I talked the junkyard into giving yet another motor but I am still holding out hope for the first one. I don't want to waste my wrenchers time on the 2nd one if I can help it. Thoughts?

[Scott_]

Do you happen to know anyone with a small bore scope? that you could look into the cylinder, valve bores, etc...

Personally, I'd probably return that one and look for another breaker with a better definition of "a few years".
I have a car in storage for "a few years" that's going on close to 20 years now.

[wmax351]

Yeah, K75 engines are plentiful. Return it and get another.


If you feel like it, the gasket kit is pretty cheap from motobins. When I put a craigslist engine in mine, I tore it down completely and inspected/cleaned the whole thing. Worth it, imo. Totally oil tight, and I know it's solid. Also got the grit that had fallen into the cylinder through the port during storage out.

[xians421]

Thanks guys. I actually got the yard to give me another one without even returning the first one, so I'm crossing my fingers.