ER5 Carb balancing - one dial steady, one not

[andy_uk]

Okay...I have previously used a manometer style balancer but this time I was lent one with dials instead.
I hooked it up with both dampers wide open, one dial was as steady as a rock, the needle on the other was almost hitting both end points.
I could steady the needle with the damper almost closed but surely there shouldn't be that much difference between each carb?

Valve clearances were spot on and the float levels were fairly close.

Any ideas or is it normal?
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Aprilia Classic 125, GS500E, ER5-A1, ER5-C4, ER6 & an XJ6 project frame...

[mentalboy]

Both needles should be trying to knock the shit out of themselves if the dampers are opened up. The steady one must have a closed damper, unless the gauge is FUBARed.
The dampers should be all but closed. The best way to preserve the gauge internals is to close down the dampers before you start and then ease them open until they just start to shudder. The idea being that you have enough shake to be able to read the dial, too little and it's likely that you've closed it down, too much and you won't be able to read it - unless you've got an impressive bout of Parkinson's where your tremors match the shake
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Make mine a Corona.

[RhynoCZ]

[331X2]

Swap the gauges on to the opposite cylinder, if the fault moves to the other gauge then the bike is the issue, if it stays on the same gauge then it's the equipment.

[Islander]

Just increase the damping until it's reasonably steady.

[orac]

get it hot, spray WD40, brake cleaner or something similar on the intake rubbers to make sure there isn't a leak causing it not to pull vacuum.
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Current rides - 2016 Triumph Street Triple Rx, 1994 Suzuki Bandit 400 VM, TGB 204 Classic 125cc
"with nothing left to lose, there is everything to gain. It's not the size of the dog in the fight, it's the size of the fight in the dog"

[RhynoCZ]

[Islander]

Why invent a problem where none probably exists?

It's perfectly normal for dial type vacuum guages to flutter - the vacuum in the inlet isn't constant. This is why they have valves inline to provide damping. The normal procedure is to close the valve until the needle becomes still, then back it off slightly so that it begins to flutter. Do this for each dial and then balance the carbs. Don't forget to blip the throttle a few times after they're balanced to make sure they settle back to the same reading on each gauge.

Dials are as accurate as liquid manometers - the main advantage of the liquid type is that you can knock a set up yourself if you don't have anything else to hand.

If you're really that worried about the gauges, you can check them by swapping the tubes over - any variation between readings should swap as well.