Three small Moby 50V questions

It's supposed to be a beautiful day here in Pittsburgh, which is a rarity in itself, and on a weekend-- that's unheard of! So, I'd appreciate your help with these three small questions, and then I can get to work.

First, I got a copper gasket for my exhaust, which came with a crummy steel crush washer instead. It's split on one face (rather than the outer perimeter, like I expected) and seems to be filled with some fibrous stuff. Does anyone know if I should put the split side towards the block, or towards the pipe? I'm thinking towards the block, but wanted to be sure, since I can only really crush it once.

Second, I had a rag tied over my carb's air inlet when I went for my first ride (my airbox is gone), and when I got back it was soaked with gas & oil. What would cause gas to come back out the air inlet? I did take a small spill once, is it possible that the bowl could have drained out this inlet?

Last, anyone know if a gas cap from a '71 50L will fit a '78 50V?

Thanks a ton!


Re: Three small Moby 50V questions


The gas caps should interchange. As fas as I know, most all 40/50 stuff swaps around fine, over many years of production.

It's not unusual at all to have a 2-stroke spit mixture out of the intake; it's pretty darn common, actually. Having the correct airbox will help this to some extent. And yes, if the bike was tipped over it could easily have dumped liquid fuel out of the carb.

As for the gasket, I think you are correct - put the split face against whatever has the largest and flattest surface. In this case, that should be the cylinder. Not 100% sure about this, though.

Re: Three small Moby 50V questions

Legendre, I'm glad the bike you found in the trash happened to be the same as mine, because you seem to have accumulated a ton of useful knowledge about it. Thanks for the help!

Re: Three small Moby 50V questions

Mike Scouty McScoutington /

i dont knwo about the gas cap. it should work but those damn french and their over engineered hyper specialized parts. i have a '79 50v and my buddy has a '78 50v and a lot of the parts are specific to one year. whats more they like to use "french metric". that means if you ever need to match up any threading on your bike good luck. i took a screw into a hardware store that has an unbelievable nuts and bolts section and they couldnt find anything that matched the pitch of the threads. the guy was really confused as to what i had.

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