Advance unit

[auxtian]

Does anyone know if the vac. advance unit have a damper in it or does the plate pulse with the revs. Goes around OK just is not smooth
Thanks

[TopCatGr58]

Hey there Auxtian,

The damper it needs is in the small sized tube on the "CARB" body that it is supposed to attach to. Sounds like you have it attached to the Intake Manifold port instead!?
T.C.

[auxtian]

No I have it the right way around
It is just that the plate is pulsating and it's so long since I had to do anything in that area I can't remember if it pulses or just sits there till the revs come up. Even when they do it still pulsates. All started with a pair of broken pickup wires so thought I would change the intakes and check the carbs...bum should have let it be till its neck 5 year service

[TopCatGr58]

Okay,

I remember reading a post about how the vacuum kicks in more as the throttle plate is opened, exposing more of the port hole inside the throat, so possibly your butterfly is too far open for idle!? I can't remember if it pulses or not at idle, but I think not much if at all.

Have you checked to ensure that the unit will HOLD a vacuum, applying vacuum to it, then clamping off the tube to see if it stays in place or slowly moves/returns, which could indicate a leak, and perhaps a reason for pulsing!?
T.C.

[Hobbit]

plate

My xs does the same thing as Auxtian's, the plate pulsates at idle. But the bike runs fine.

[auxtian]

Have been working on it most of the day Sunday here
Took the new inlet boots off removed the supplied gasket put on some gasket goo drank 4 bottles of Coopers Red (Aussie (real) Beer 6%) went got a burger watch a 16 y/o do Somebody to Love on Australian Idol now it is raining so I'm going to try out my efforts
Will keep you posted
Thanks all
CR

[dntemp_ca]

There have been a few threads on this topic....I'm beginning to think this is a common trait of the XS11. The advance on mine pulses or chatters too. I've replaced the carb boots, cleaned and synced the carbs and dismantled and cleaned the mechanical advance mechanism. It's better now but it still chatters a bit, mostly at highway cruising speed. If you have a fairing, you probably notice the clacking noise caused by the advance chatter more than those without fairing. (Yes, I have the vac adv hose hooked up to the proper nipple. Yes, the diaphragm holds the vacuum. Yes, the nipple damper hole is clear.) I'm gonna take the whole advance mechanism apart soon and clean and lube it again. I've put about 10,000 kms on my XS since I bought it and it runs great. But I wish I could get rid of that vac chatter and clacking noise. It just doesn't seem right.

[uk1.1s]

Chatter

Yep - seems about right.

My bike was out of commission for a while and about 2 years ago I posted with the same thing.

Mine WAS owner error tho' - just hooked it up wrong and it REALLY made a noise.

Connected up to the carb body stub with a nice new hose and vac advance unit that held a vacuum nicely and it has quietened down.

But it's not silent and yes I can hear a slight chatter still. Haven't got a big fairing tho' so nothing too bad reflected up. Spare advance I have does the same - so not a dodgy diaphragm in the unit....or both are bad!!

Mine is one of those without the mechanical advance (fully electronic) so I can't do anymore to try to make it work more quietly.

[auxtian]

I found also that the lug that the vaccum unit slips onto is a bit loose so looks like I may have to get it spot welded from the back...yuk...
But since I did the pickup wires that is OK, deciding to do the carbs was my big mistake did the levels and balanced but now idle is crook if I come to a quick stop sometimes she splutters and if I don't blip the throttle it stalls....back to the drawing board.....fuel injection soon