Questionl982 yamaha seca 650 turbo burns oil and leaks oil out of the baffles when not running (not lots, like a tablespoon or so over night). its not the stop-check valve, or broken line.
AnswerHi Chris,
Most often the gravity slowly pulls
oil down into the exhaust through the turbo seals.
This is what happens also when the check valves have a slow leak.
There is a check valve in both the feed and return oil lines.
Due to the age of the bike all the seals
are in question as well as the
condition of the cylinders, pistons and rings.
A leak down test can verify if the
rings are sealing all through the
movement of the piston.
Some cylinders will have good compression
yet have a ring seal leak as the piston moves
down the cylinder.
This can result in some oil blow by into
exhaust and breathers.
Leaking carbs can simulate an oil leak
by flooding the exhaust with
fuel and mixing with exhaust soot.
A bad fuel valve or carb float valves
leaking might be the cause.
Check also for fuel diluted oil which
might drip out exhaust.
If you can do a cylinder leak down test
and confirm the engine ring seal and
valves are okay then it
might just be leaking turbo bearing seals.
A worn Mitsubishi TC03-06A turbocharger can circulate engine oil
through the air induction into the carburetors and back into the engine
and eventually into exhaust pipes. This is usually
a sticky check valve and/or a turbo bearing seal problem.
There is a turbo failure check list here:
http://www.jhdiesel.com/failurechart1.htm
Turbo for sale:
http://www.invasionautoproducts.com/tcmotu.html
Rebuild turbos:
http://gpopshop.com/services.html
Good luck!
Wayne S.
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