carb vacuum

[okflyer1]

I just rebuilt the carb's on an 83 1100 interstate, while trying to sync the carb's, I removed the hose from the #2 manifold and noticed a pulsing going on thru the adptor for the sync hose, ran a compression check, 150 on all 4, any ideas, also plugged the vacuum advance hose, would not hold a vacuum...

 

[scdmarx]

I haven't been through a carb sync yet on the wings. But with a vacuum gauge connected directly to manifold vacuum, a steady pulsing usually indicates a valve problem. If the compression test closely matches the other cylinders, but the vacuum gauge pulses on one cylinder, I'd be suspecting a valve adjusted too tight.
Or I could've misunderstood you question completely. Take your pick. :hi:

 

[jdegase]

my vacuum gauges have little adjustable valves (in each hose) to take the pulse out of the vacuum, if you dont adjust this valve its very hard to read the needles.
not sure if this info will help you.
my set is a 4 gauge set and each hose needs to be adjusted so the needle is steady. then you can adjust each carb easily

 

[slabghost]

my vacuum gauges have little adjustable valves (in each hose) to take the pulse out of the vacuum, if you dont adjust this valve its very hard to read the needles.
not sure if this info will help you.
my set is a 4 gauge set and each hose needs to be adjusted so the needle is steady. then you can adjust each carb easily

:yes: yep! on our bikes you read each cylinder vacuum seperately. So each one does pulse.

 

[RBG]

They are supposed to pulse and if your advance does hold a vacuum you need to fix it if you want the bike to run correctly at speed..iE buy a new unit or fix the diaphragm in there..not sure if it can be "fixed"

 

[slabghost]

They are supposed to pulse and if your advance does hold a vacuum you need to fix it if you want the bike to run correctly at speed..iE buy a new unit or fix the diaphragm in there..not sure if it can be "fixed"

Do a search for littlebeavers thread, He came up with a fix.

 

[dan filipi]

Here's that thread.......all 14 pages, Oy!
viewtopic.php?f=23&t=1468&hilit=vacuum+advance