Parts Question, thanks!

[8SpadeEpiphany]

So mechanics told me the advancer diaphragm is shot on my bike. I posted a parts request for some carb boots (unrelated) and the advancer diaphragm (part number: 3H5-81683-09-00). Someone was awesome enough to respond on both parts but I wanted to make sure that the part was what I needed. It's described as the "pickup coil assembly is the entire assembly,everything under the left engine sidecover,vac pod, pickups, plate,wiring etc" Does this assembly have the advancer diaphragm I require? Any help would be awesome.

Thanks guys!

[TopCatGr58]

Hey 8Spade,

The Vac Pod in the description IS the vacuum diaphragm assembly. However, that part # looks like it's off an 80 model, but haven't checked it against the Official Yamaha Microfiche site! IIRC, the centrifugal advance parts provide a little LESS timing advance vs. your 79 parts. However, you're probably only going to be needing to take the vac. pod off of the timing parts assembly to replace yours that is broken...per your mechanic's statement?

Yes, these things do go bad, get holes in them, and they are NOS from Yamaha, so used is about the only option. I've meant to go to my local auot store and see if I can rumage thru their parts to try to find an automotive unit that would be close and not to hard to modify to fit our engines, so at least we would have another option!
T.C.

[bikerphil]

I've repaired those vac. pots before. You can carefully pry them open and seal the hole in the diaphram with RTV. Crimp it back together and you're done. The one I repaired has lasted 2 yrs. and is still holding. Ebay also has 'em from time to time.

[tw1980]

I think I remember reading some posts where people were running without vac advance hooked up.Try your search function If you haven't already tried that.

Terry