Small oil leak under gearbox/shifter

[mobius]

Hello,

Excuse my ignorance as I may not be using the correct terms to describe the exact location of the leak. I will try to upload a picture later.

I have a "77 GS400. Recently replaced the oil, rode it for 30 minutes, parked for the night. The following morning I noticed a couple drops of oil coming from under the shifter/gearbox.

Questions:
Could this result from too much oil (may have added a bit extra) or would this be more geared towards a faulty seal?

I just find it odd that it only starting to leak after an oil change. I made sure the bike was clean and no oil residue was present.

Leak is located under gearbox, in-line with the base of the shifter.

 

[Guest]

Probably the seal for shift shaft, remember the bike is39 years old rubber seals don't last forever

 

[Gorminrider]

indeed^^^^ very common issue. clutch seal also a possible. Usually you can see it leaking when you take the sprocket cover off ...UNLESS you have just oiled the chain which sprays around in here and drips out too, but the latter ceases after less than 50 miles

 

[chuck hahn]

Good news is the shifter seal is an easy change that doesnt require any engine removal or cases being split. Drain the oil, screw a drywall screw into the seal between the shifter shaft and the outer rim of the seal and yank on it with vice grips.

Clean the shaft with some degreaser and get all the rust and crud off. Then put some plastic wrap on the knurling at the end ( or a wrap of electrical tape ) to protect the new seal when installing. Slide the new seal in and get it finger started. Now use a small piece of PVC or a pipe nipple that fits the outer rim of the seal to tap it in and seat. Done.

 

[mobius]

Thanks for filling the knowledge gap. After removing the sprocket cover, it looks like the leak is coming from shaft seal.

How much oil is behind this little seal and is it pressurized?

Also, having trouble finding a reliable source online for this seal - any recommendations?