Diaphram looking valve near the igniter

[Avidrider62]

Any one ever tested these to see if they work? Carl is slightly lost and his friend connection is too. Here's what happens. The bike needs vacuum advance to warm it up. If not , if farts, snarls, pops. When very warmed up and with igniter hooked to number 1 carb, upon rpm deceleration, engine wants to hang a 1800 rpms. Bike behaves good with no vacuum to the igniter when hot.
Short of buying a new one, if avail, any ideas how to ensure it's the diaphragm issue. Oh, I have a few parts to and kept trying them too.

[ekap1200]

Back in the way-backs, auto engine's had these items all over their vacuum lines.
Most were delay lines. If you have a hand held vac/pump and a vac/gauge you can see what it IS DOING. And then compare it to someones that has no issues.
Be sure of how it is connected as to the direction before removing it. Most were color coded as to the direction of applied vacuum. Apply vac slowly and watch your gauge on the module side. It may delay the applied vac or not. Now release the vac at the hand/pump, it may or may not delay the release of the vacuum. It may even , delay in one condition only ie. at applied vacuum and not in the release of vac or delay in both directions. With no information on it, comparing vac readings on a known one, of good condition is the only way I know of too accept/reject it. Gene Kap.

[Avidrider62]

other trick to fix i heard is a vacuum tee and then a restrictive device, ie..small carb jet, to change the vacuum.