Motorcycle Repair: 1980 Yamaha 650 Special Valve Job, valve seals, pan gasket


Question
QUESTION: Hello Sir,
I have the above mentioned bike. I am leaking oil out of the joint and end of the muffler on the right side. I spoke to professionals and they suggested a valve job for 1200.-1500.$.
Is there a site with a step by step procedure for this act? I have the book, but i talks about total dismantling of the engine. I am about to take the top part of the engine off, not sure of what to expect.
Thank you for your time.

James


ANSWER: Have you checked compression?

Oil in the exhaust dosn't necessarily mean a full valve job but may just need vavle seals. Valve seals will require the top end to be removed.

A compression test will tell you a bit about the condition of the valves and valve seats.


---------- FOLLOW-UP ----------

QUESTION: Thank you for your timly response.
I have already dismantled the top of the engine so unfortunately its too late to run a compression test.(excited & impatient) How will I know if the valve seals need replacing? Will they be decomposed or cracked?
Thanks again for your time.
James

Answer
A leaky seal is not necessarily broken or cracked. But if you are getting oil drips from your exhaust I would expect to see something obvious in the seal.

BTW, it is common to get fluid dripping from the exhaust. This happens when the exhaust is cold and water vapor condenses and drips out. The water vapor usually comes out looking oily and will smell so often people mistake it for oil. Oil coming out of the exhaust will be black. Are you sure its coming out of the exhaust and not from some other location (oil pan gasket, head gasket, cylinder base gasket). Just a thought.