twinmax carb synch tool?

[dpotter58]

http://www.rlmotorcycles.com/home/ac...es/TwinMax.htm

Anyone ever use this?

[Ken Talbot]

For the life of me, I can't figure out how this unit or any of the one-at-a-time gauges would work. They look like they would do an excellent job of setting one carb to a particular vacuum level at a particular point in time. Everything I've read about synchronizing multiple carbs works on the principle of setting two of something to an identical value, whatever that value happens to be. I.e., you sync one carb to another, or you balance left side to right side, etc. You do a number of iterations of this and you end up with everything exactly the same.

It seems to me that the moment you disconnect this electronic unit and move it to another carb, you lose any reference for setting the next carb. As you adjust the setting on the new carb, it changes the motor speed, which then changes the vacuum in the carb you just set because it is also now operating at a different speed. You're now setting the new carb at a different engine speed than when you were setting the first carb.

We need to head from some others who use individual gauges to hear how they get consistentcy. There must be a way, but I just can't imagine it.

[randy]

Ken,

My sentiments exactly. The carbs are inter-dependent. Can't synch them unless you can read ALL FOUR of them at once.

[planedick]

Not so...

I have a mercury type that is missing some mercury, so I connect only two lines at once, one stays on the # 3 carb as that is the one that is connected to the idle stop and just move the other line to each of the other carbs in turn. Just remember to do # 2 before # 1 as # 2 effects both, and do # 4 last. Works for me.

[Trikerneil]

I calibrate similar units to this for a living

If you connect that instrument across two carbs the meter would read zero when they were balanced.

You'd then have to balance another pair or use one carb as a referenece to set the remaining three.

Just my 2p worth

[81xsproject]

I use the homemade sync from the tips section with one gauge. It is entirly possible. I just swith back and forth on the fish tank vacuum valves until there is no difference between the two I am sync'ing. Probably would take me five minutes if I didn't get paranoid of overheating and shut the bike down for a few minutes between sets.

[randy]

81xsproject,

If you're worried about overheating when doing a synch, set a box fan in front of the motor.

[desert1]

Gauges

I have 4 vaccuum gauges but really need a pictorial set of instructions to be able to set them up, I have no bleed valves or manifold to hook them to all I need is some guidance, please any takers?
Bruce

[DiverRay]

Bruce,
I would mount all 4 on a board, and run the vacum lines from each one to a carb. If you use 4' lines, you can lay the board on the ground, prop it against the handlebars, or whatever to read it easily.
Then it's just a matter of trying to get all 4 gauges to read the same.

[Ken Talbot]

Originally posted by Trikerneil
I calibrate similar units to this for a living

If you connect that instrument across two carbs the meter would read zero when they were balanced.

That's the part I cannot visualize. How do you connect 'across two carbs'?

[Trikerneil]

There are two pipes sticking out of the bottom of the unit.
Connect each pipe to a vacuum nipple on a carb rubber and the difference in pressure could be read.
If you look at the larger picture on their site the scale is zero centred and reads plus or minus values.
Zero would indicate the carbs were balanced.
If one pipe were left open to atmospheric pressure then vacuum referenced to atmosperic could be read assuming the unit could handle that range pressure differential

[Ken Talbot]

Aha! I can "see" it now. That makes all the sense in the world. A unit like that would be a lot easier to pack around to XS rallies for tune-ups-on-the-spot than a set of mercury sticks. Might have to give that a bit more thought....