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Hello, all,

I'm reviveing a '92 ZX-11 C3 after fifteen years storage. Stuck valves have required I remove the head and address that.

I had injected a couple of ounces of motor oil in each cylinder via the spark plug hole, let it sit for a couple of days then very
gently began rocking the bike back and forth in an effort to break free any stuck rings (if there were any, just as a precaution).
No problems there.

However, when I got the head off I notice a significant difference in the amount of deposits on the piston tops. Of course all were
oily but #1 and #3 had what I considered excessive carbon buildup. A compression test would not have told me much due to the
sticking valves.

I want to propose a possible explanation and see how it floats with fellow forum folk. On the C model the hose from the
crankcase breather/separator beneath the battery enters the carburator air-box in front of the #1 carburator. The output
of the vacuum operated crankcase ventalation devise on top of the valve cover enters the air-box near and infront of the
#3 carburator.

So, if the carburators are performing properly (float bowl heights correct, no clogged jets, etc) and are well synchronized (as I've
done in the past) could the deposits on the pistons be due to combustion blow-by and oil vapor from the breather and vacuum
crank ventilation system?

I'm considering removing these two hoses from the air-box and routing them elsewhere with some oil resistant foam at their
ends to prevent ingress of dust, squirrels and small children when at speed. But definitely not near the rear tire.

There is really no telling until I get the bike running and do a compression and leak-down test whether the rings are passing
oil or not.

Nevertheless, I'd enjoy hearing and discussing your thoughts on this possible problem.

H.
 
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