Quick question about carb bench sync

I'm going to do a bench sync after rebuilding my VM24ss. I'm a little confused as to the position of the idle adjust screw before I set the slide heights and I'm hoping you nice folks could clarify something.

The purpose of the wire method is to make sure the slides are all at the same position relative to each other? and I need to have the idle adjust screw far enough in to be able to lower the slides to a complete close after I set the height with the wire? Does this sound about right? I'm just trying to understand the method before I do this. Any suggestions for how far to turn the screw in?

I believe you set the idle speed ontrol screw that puts pressureon the return spring so that it can be adjusted in either direction once you get the carbs on the bike. That way if it's too high or low once it's on the bike you can adjust in either direction.

Yes, the wire method gets the slide heights the same across the rack. Based on varying cylinder pressures, etc, the gauge or manometer method gets them accurate once on the bike and running.

One last quick question. Am I putting the wire at the bottom of the carb bore on the air box side or the engine side? Sorry if this is a stupid question.

bloglos wrote:

...Am I putting the wire at the bottom of the carb bore on the air box side or the engine side?....

Engine side.

bloglos wrote:

One last quick question. Am I putting the wire at the bottom of the carb bore on the air box side or the engine side? Sorry if this is a stupid question.

Not stupid. Do you have the service manual? I think it states it in there, but I would default to the all knowing, all powerful General (Mod) Patton.

bloglos wrote:

One last quick question. Am I putting the wire at the bottom of the carb bore on the air box side or the engine side? Sorry if this is a stupid question.

Not a stupid question. Use the engine side.

Screw the idle screw all the way in, then back it out 1/8th inch. This is your starting position. The raise each slide enough to put in the rod (engine side). Lower the slide so that it holds the rod in place just gently. Tip the carb over (engine side w/rod facing the ground), then slowly raise the slide. When the rod falls out, stop and tighten the adjuster nut. Repeat for other cylinders.

After you are finished, the slides should all be visually at the same amount of opening (approx 1/8 inch), and the idle screw should still be in the starting position.

Now unscrew the idle screw so that only about 1mm of gap is visable at the slide bottoms and you're done! The bike may need slightly more when trying to start for first time.

Once installed, you may need some more or less idle but remember to make the final idle adjustment after the bike has been ridden for at least a half our.

Maonometer syncing and idle mixtures should be done before final idle adjust.

Peace!

DoubleDub wrote:

...have the service manual? I think it states it in there....

Brings up a good point, and maybe I've overlooked it, but don't see conclusive text in the FSM about which end of the carb to deal with when bench syncing.

However, Sudco's Mikuni Tuning Manual is very specific:
With the carbs on the work bench and the spigot or engine side of the carbs facing you, [etc.].

Good Fortune!

I believe you want to use the engine side of the carbs because the slides have a cut away on them one the airbox side.

Sweet thanks everyone. I do have the factory service manual, but it definitely does not mention which side. I'm going to finish up the bench sync and then put them on the bike. Now it's time to de-rust the tank and hopefully this beast will come back to life after 19 years of sitting in a garage.