Motorcycle Repair: 1982 Maxim 550 problem, crank case, vacuum line

Question
I have a 1982 Yamaha Maxim 550 that runs good when it is running, however after running for a little while, the crank case fills up with gas and starts coming out what i believe is the breather tube. I am not sure where to even start looking to fix this problem. I have been told that it may need rings and other people have told me that it might be the floats. Any help at a point in the right direction would be great.

Thank you for your time,
Jim

Answer
A bike where gas gets into the crankcase is usually due to bad float valves in the carbs. You probably need to clean the carbs and replace the o-rings around the float valves.

If your bike has a vacuum operated petcock, the problem can also be that excess gas is flowing into the carbs from the petcock. You should test the petcock by sucking on the vacuum line and see if there's any trace of gas there.