Modern Buddy

I smelled gas in my oil after a drain and refill of the gear oil this weekend. I am assuming it is a clutch side seal leak. I have two questions for the forum.

1. Is there any other cause for a gas smell in the gear oil? If so, how would I trouble shoot that also. I just want to make sure I cover all bases.

2. In the event I do need to replace the clutch side seal, what items should I replace, since I am cracking the engine to get to the clutch side seal.

I already am assuming I will be replace the clutch side seal (main), flywheel side seal, and hub seal. I have heard suggestions of replacing the cruciform also. The scoot is a 2005 Stella with 3400 miles. It has not been driven much, so I am suspecting the clutch is fine, so I would like to save the money on that part.

Unless you are shifting hard I doubt you would need a cruciform so soon.

You will want new gaskets for the clutch, reed block, and case halves.

Thanks. Are you aware of any other reason (besides clutch side seal)that there would be a gas smell coming out of gear oil when drained?

I have heard people say eliminate anything else before you try to change out the clutch seal; however, I have yet to find what other things need to be eliminated.

Also, this particular Stella is always on a side stand. I have heard this could lead to some issues. I am going to go ahead and put a center stand on just out of an abundance of caution. ... and it looks nicer.

My 2T's have the cold weather plug removed from the back of the carburetor so any blowback from the engine runs down the back of the case.

I'm not sure if I could smell the difference of gas vs no gas in my oil.

Do you have access to a shop that could do a leakdown test? That'd indicate if you have a bad seal.

I was running it with the winter plug out. I recently rigged up a new plug with a drain hose in it, but I have yet to use it much (I need to post it up under tips and tricks or something).


Just for clarification, I am talking about the final drive/tranny oil/Drive Oil/Gear Oil. I just call it gear oil, but I may have the nomenclature wrong.

When I catch the smell, I am not smelling it on the bike, I am draining it and smelling it while it is in a container well away from the bike. You can definitely smell a bit of gas.

I will go ahead and plug it up with the modded winter plug and test it again.

As to the leakdown test, I will look into that, but I really don't have access to a shop. Nevertheless, my original goal in this post was to figure out what I would need to "rule out" other potential causes of gas smell in the gear oil