What is this gunk!? 1983 Honda CB550sc

Took off the oil pan and pump from my ’83 CB550SC. This is what I saw in one of the parts (it’s not the strainer, it’s not the pump itself, it’s not oil tube, I think you’ll recognize the part).

Oil pump

It was almost totally gunked up with some rust-colored goo. No idea what it was. But I’m pretty sure it would be at least hard, if not totally impossibly for oil to pass through effectively.

Any idea what this stuff could be and whether or not it might be a sign of something to worry about?

fyi, this motor was sitting for several years after having its oil drained. I did find a single small fleck of metal stuck in the oil strainer. Not sure if those tidbits will help diagnosis.


Looks like you had some water in there somehow. You can get some condensation in a motor, particularly if it’s stored with no oil in it, depending where you keep it. If the temps drop low in the storage room condensation can definitely happen.

For long term storage, put fresh oil in the motor, then put a piece of tape over the air intake and the crankcase breather.


Evan Fell

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