I'm Rich!

[leonvjames]

When my bike (CB77) was new I had several cases of cracked pistons in the first 30.000 miles. I put this down to too smaller main jet. Mixture was just a wee bit lean on the standard 120 jets so going to 130 should help to eliminate this problem. I went to a 350 kit and all the changes that involved. Now done 135.000 miles and had other hassles but no more cracked pistons.
Leon.

[mustanger]

Sounds like you had the opposite problem than this one. However, it's still interesting. I know that leaner mixtures cause the motors to run hotter, but so hot you cracked the pistons??? Didn't you hear the hear the engine knocking before this happened?

[leonvjames]

no, the motor tightened then just seized. I used to pull in the clutch and coast for a while then drop the clutch and proceed a bit slower followed by clouds of blue oil smoke. Used to use a fair bit of oil then so I resorted to running the breather into a plastic bag or bottle to catch the oil blown out and then every so often just tip the oil collected back into the sump. I managed to get home most times like this. Interesting times.
Leon.