Topic: Bench sync

[la ca fe]

I’ve been looking on YouTube for a good cb750 bench sync video but no luck. Just finished rebuilding my carbs and set the float height.
Does anyone have a good bench sync method for a 76 cb750?

[HondaMan]

I use the 'zeroing' method most of the time, and very few times has it needed vacuum balancing afterward.
But - this presumes a K1 (or later) style carb slide rack, which operates all 4 carbs together: if you have the 4 individual cables instead, it's easier to balance it with vacuum gages: you'll need 4 of them, like from Motion-Pro or similar.

[Medyo Bastos]

I’ve been looking on YouTube for a good cb750 bench sync video but no luck. Just finished rebuilding my carbs and set the float height.
Does anyone have a good bench sync method for a 76 cb750?

Houndog has a nice guide in the garage:

http://www.hondachopper.com/garage/carb_info/bench_sync/bench_sync.html


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[Deltarider]

Mechanic Trigger in the UK site has restaured many CBFours. I quote him: "WD40 straw works fine with me and no damage to the slides  "
I myself also used to do it engine side with a small allen key, taking extreme care not to damage the slides, but a WD-40 straw is safer.

[seanbarney41]

I use the 'zeroing' method most of the time, and very few times has it needed vacuum balancing afterward.
But - this presumes a K1 (or later) style carb slide rack, which operates all 4 carbs together: if you have the 4 individual cables instead, it's easier to balance it with vacuum gages: you'll need 4 of them, like from Motion-Pro or similar.

+1...back off the main idle screw til it is not touching, adjust individual sync screws so that each slide is just fully closed, turn in main idle screw so that they are open just a ctack.  This should allow the bike to start and not immediately rev to the moon.  You may have to give a little extra throttle to start.  Adjust idle speed with the main screw once the bike is fully warm.  This will usually get your sync pretty close.

[la ca fe]

I’ve been messing with cb750’s for years and every once in a while there is a new task I’ve never tried before, like in this case the process of rebuilding carbs. Thanks to you all I’m getting this part of the process done and now I know how to do it again.