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Been trying to balance my carbs, to see if I could rid myself of the vibes which are
the same as described in another thread. All of the vibrations actually come from the
carbs, and none at all from the engine itself.
Not sure I'm having much success with the balancing, and it all seems to keep changing.
My mates vacuum gauges are the type with the metal rods that slide up and down in
the glass tubes.
Any ideas why the carbs would be vibrating, and how to fix (or balance better)?
Not knowing enough about carbs, I don't understand where the vibrations are coming
from. There are no moving parts as such, are there?

air pulses through the carbs.. which is why they vibrate a bit, fitting the airbox goes some way towards stopping the vibration as it is securely located.

the solid bar vacuum gauges arent really that good tbh.

Thanks for the info. I now know a bit more about carbs. Re-fitting the air-box
might help things then, worth trying to see what difference it makes.
Any suggestions for an alternative to the solid bar gauges then? The only other
type I know of, is the ones with dial gauges.

cheers

I think you can get mercury ones too, but are a bit dodgy as you can suck the mercury into the system.

Ive got dial gauges, myself.

i'd go with quality dial gauges

Dial gauges is the way to go then.

cheers

zimm wrote: the solid bar vacuum gauges arent really that good tbh.

i thought they were the best? did a spot on job on my gixer.

carbtune by morgans are supposed to be one of the best and they are mercury bars. Are they lying?

parby81 wrote:carbtune by morgans are supposed to be one of the best and they are mercury bars. Are they lying?

those are the ones i used.

I had a carbtune bolted on, at the weekend. Worked a treat.
Give the tubes a light tap to help settle them.

Do you have the restricter straw bits fitted? They are like straws with a very small hole in them close to the end of the pipes that fit onto the manifold?

Yeah, each tube appears to have a section near the manifold end, which are the
restricting, or damping the gauges.
I just don't think the whole balancing thing should be as difficult as I'm finding it.
As I turn each screw, I have to be really careful not to apply pressure, as that
revs the bike. But as you turn say the screw for carbs 1 and 2, you'd expect
the gauges to balance when turning one way, and going out of whack when going
the other way, but the whole thing seems a bit erratic.
Wasn't sure if it was me, the gauges, or some other factor that I'm missing.

Have you checked the needles / slides for scoring, jets for gunk, linkages for wear, free movement of floats,,,,,?

it takes time and patience, and yes if you push too hard the bike will rev as these are attached to the throttle butterflies. Need to be very gentle, small increments at a time and take the screwdriver off and blip the throttle to settle it all. Look at the gauges then go again, till you get it spot on.

Had a good look at everything in/around the carbs, and nothing in particular looks
knackered (to me!).
Maybe the technique I'm missing, is the small change, then the blip, let it settle
then go again.
That was one of the things that was confusing me about the gauges. You're tweaking
and two of the gauges are at a particular level, and by accident you press too much and
rev the bike. The gauges then seem to be sitting at another level, and not always as
close as they were when you were adjusting 2 seconds ago.
On the other thread, the person said that he (she?) had balanced the carbs at idle,
and was getting the fine vibrations up through the bars. Once the carbs were balanced
at 3k, rather than idle, the vibes went away.
Is 3k a good level to be running when idling? Thought I'd read somewhere about setting
the bike above idle when balancing, but can't find it now.

Hi,

There's a little thumb screw hanging down by the clutch/res bottle. Turn that screw clockwise untill the bike sits at 3000rpm, make sur ethe bike is warm first though. I found that when balancing the carbs, if you get someone to hold the throttle backwards, meaning holding the throttle closed on the bar (away from you) the bike doesn't rev when playing. It's best to balance carbs above idle at 3000rpm. like others have said, blip the throttle after little adjustments to give you the proper reading.

Regards

Rich