Honda Express tranny oil dillema

I'm trying to resurrect a 1977 Honda Express II. It runs, but will intermittently start blowing oil out the transmission case vent. It may go for days without this happening, but when it does, it pretty much pumps out the case and makes a hell of a mess. The manual specifies 10W-40 motor oil to fill the case, and I fill it only to the bottom edge of the fill hole, as instructed.

I haven't had the thing apart yet for fear I'll ruin a seal or gasket I won't be able to replace. I'm thinking maybe crankcase gasses getting past the seal between the crankcase and the transmission. Any ideas before I tear it down?

Re: Honda Express tranny oil dillema

Jonas Quimby /

I had my bike do this for awhile. Confused the hell outta me.

When I ended up doing was tearing the tranny apart to inspect the clutch (it was fine) and putting everything back together. But when I did, I first cleaned everything really well, and then refilled the tranny with all new oil.

The last owner had taken apart the transmission without knowing what to put in it afterwards. As such it was running with something far too thick in it.

If you havent fully drained your oil yet, that might be something to consider. Something about the two types of oil not mixing right or something...

Re: Honda Express tranny oil dillema

there are places to get the gaskets online... not the cheapest, but you can get em

Re: Honda Express tranny oil dillema

You know, that was the first thing I tried. I figured it was either overfilled or running gear oil instead of the 10W-40 specified in the book. I let it drain overnight, then filled the case again. It worked well for a few days, then started pumping out again. Pretty weird, considering how much higher the vent is than the oil level. Even allowing for expansion of the oil, it shouldn't be coming out of the vent! The only thing I can think of at this point is that the chain might be carrying the oil to within striking distance of the vent, or, like I said in the beginning, crankcase gasses could be passing through the seal and foaming the oil. I'd think there would be performance issues there though, and the oil looks bubble-free. Puzzling. Thanx for the comeback though.


Re: Honda Express tranny oil dillema

Can you point me to a likely site? Thanx.

Re: Honda Express tranny oil dillema

Search for NC50 in eBay, there is a guy that has a full gasket set with a starting bid of $5. Or just use an automotive silicone that is oil resistant.

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