87 Carb Issue - another type of diaphragm

So.. I have been battling a carb problem with my 87. After checking the exhaust pipes to see if they were firing equally, I found the front right wasn't getting hot. Finally broke down and pulled the carbs.

( background: bought the bike from a guy who had it parked in his airplane hanger but had it parked over 2 years with gas in it.)

First I found the previous idiot... I mean owner, used regular clear silicone all over. In the intakes, in the carb bowls..just everywhere. And as a bonus he left me with a lot of stripped Phillips screws. Got the screws out and replaced with ones from my parts carbs, but the worst part is that I found these little diaphragms look pretty wrecked. This one ( below) looks like he used some pretty harsh cleaner trying to get the bike running.

I am guessing that these are like some type of accelerator type diaphragm. The Boats.net site says they are $40.00 each.

Are these cheaper any where else ?

I have checked the other ones and although the first one was the worse, the others look a little beat up too.

 

I am guessing that these are like some type of accelerator type diaphragm. The Boats.net site says they are $40.00 each.

 

Are these cheaper any where else ?

 

I have checked the other ones and although the first one was the worse, the others look a little beat up too.

You can find these on ebay for a tad under $20 each often.

http://stores.ebay.com/Sirius-Consolidated-Inc/_i.html?_nkw=venture+air&submit=Search&_sid=24743148

Item # 370775305262 if link doesn't work.

Gary

I am impressed with his silicone work. Here's what we do. There is a thread right now on what to do with old helmets. I say we get the previous owner, give him an old helmet painted with a bullseye on the back, and tell him to start running. Sounds like good pellet gun practice to me! Holy cow! We can each take turns at a maintenance day......

That is the air cut off valve diaphragm. The valve reduces idle air when coasting to reduce popping. When the diaphragm is torn extra air gets in and makes things lean.

Even aftermarket the little buggers are pricey.

So, if these were bad , as the one was and the others look "effected" would that cause the need to use full choke and cause the one carb to not function ?

So, if these were bad , as the one was and the others look "effected" would that cause the need to use full choke and cause the one carb to not function ?

They'll definitely mess up the idle, which the choke would help. Probably wouldn't lead to a stone cold cylinder though.

Based on what I've seen I'd bet cash money there are more issues. Best to do the whole job.

Anybody have leads to who sells the lowest priced carb kits ? Or do I have to order pieces separately ? Also, what is the proper name for these diaphragms ? Air cutoff diaphragms ?

They aren't generally included in a rebuild kit, need to purchase individually.

Yamaha calls it "Diaphragm Set 5" and has an MSRP of $60.49. Part number 3LD-1490H-00-00 available from an on line seller for $43.55.

Aftermarket they're typically called "Air Cut off Valve". I list them HERE at $32.99. Use coupon code "VentureRider" at check out for 15% off.