Topic: Small leak under Stator case

[TheHulk]

This posting is in regard to my '77 CB550F

I've been noticing a small oil leak coming out between the engine case and stator case. I took off the case and noticed there appears to be a small reservoir at the base, and a small notch connected to it.

Is this assumption correct? Is this an oil reservoir with an overflow notch?

Then I put a small dot from a paint marker on the oil plug pictured below. After dry fitting the case back on and removing it, the paint did not transfer to the case, meaning it is not making contact, and not keeping the oil in. If that is it's actual function.

Should this plug actually be under pressure, held tight by the stator case? Or is the combination of a loose plug and an overflow reservoir part of the original design?

[Nurse Julie]

That is the main gallery oil plug, have you fitted a new O ring to see if it cures the leak?. (DON'T start the engine with the cover off, the case pushes, or should, against the protrusion to keep it in place) , the plug will blow out along with all the oil, a very big mess to clear up.

[bryanj]

If oil is comming out of that groove the plug O ring is leaking

[dave500]

if its only a slight amount of oil it could also be the main oil seal at the crank,these are an old bike now and any 50 year old seal has been doing well,swap out the o ring on that little plug,grab the little stub and it should just pull?wobble out,hopefully this is your fix,if its the crank seal its a mission plus!full engine tear down.

[dave500]

having a closer look at your photo i cant see any oil coming from above,i think youll be right just swapping out the o ring on that plug.
Honda part is # 91319-300-000,also listed as 13x2.5mm