QuestionI have oil pumping out of the breather vent when the bike is warmed up somebody told me its a compression problem can you please help me.
Thank you Andrew Wolfe
AnswerHi Andrew,
The first thing to check is if your
oil level is correct. If it is overfilled
with engine oil then it may start blowing
the excess out the breather.
There may be a filter on your engine breather
somewhere that could be plugged.
You could check the compression with a
compression gauge or do a leak down
on the cylinders.
A leak down test can tell you what and where
the engine is losing this pressure.
You apply 80-100 psi to the spark plug
hole after first setting the piston
at TDC (top dead center) and holding
the engine from turning by putting
it in gear and holding the rear brake.
With this air pressure applied you can
hear any leaks the engine has.
If the valves are leaking you will hear
air in the carbs or exhaust.
If the piston or rings are leaking
you will hear air in the breather
or oil filler.
The compression test will tell you
if the engine has a leak but
not so easily define what is leaking.
You can look up leak down test online for
details.
Breather oil is usually caused by excess
pressure inside the engine.
This is usually too much oil or
engine rings leaking pressure.
If you find a cylinder low on compression
compared to the others then that
may be the problem.
Unfortunately if it is not overfilled
or has a plugged hose or breather filter
then it may require a top end rebuild
to find the crankcase pressure problem.
If you have a piston ring stuck from
rust or carbon then running
some additive might help like "Seafoam"
If it is wear then only replacing parts will help.
Good luck,
Wayne S.
----
