ca77 top end rebuild?

Forest · Post by **Forest** » Sun Jul 29, 2012 9:12 pm

Hello Everyone. I was hoping someone with some more knowledge might give a little advice.

When I am riding I am having oil pumped out of the breather tube at the top of the engine and its coming out at a fast rate. I am assuming that the 305 engine breather tube is designed to release pressure in the engine so is it most likely that my piston rings have gone bad if I am getting oil blow by out of the breather tube?
Any other possibilities for the oil out of the breather tube?

If this is the case then I am going to drop the engine this week and do all new gaskets on the top end and replace the piston rings. Not sure if I am going to need to bore the cylinders 0.25 or if a simple honing with standard rings will work. Any guidance or warnings would be greatly appreciated!

Thank-you,
Forest

Hotshoe · Post by **Hotshoe** » Mon Jul 30, 2012 9:45 am

You might want to do a cylinder compression test before digging into the engine.
It'll help you narrow down the cause of the problem.

OldStan · Post by **OldStan** » Mon Jul 30, 2012 10:30 am

Is this a recent development on a bike that's been fine, or on one you've just acquired? If someone put the top end gaskets in wrong you can get a lot of oil out of the breather.

Forest · Post by **Forest** » Mon Jul 30, 2012 12:46 pm

This is a problem that just developed a few months ago after I took a ride through the mountains. I was thinking that all the hill climbing put extra stress in the engine and took the last life out of the piston rings. I will do a compression test but I am thinking that the gaskets were correctly installed before since it just recently became a problem.

If I was running the engine too lean would that cause the engine too run hot a wear out the piston rings faster?

Thanks for the help