bench synchronizing, what is meant by this.

[toymechanic.]

I have a Motion Pro mercury sychronizer. And once the carb are installed I used the Motion PRo to adjust and synchronize to carbs then adjust mixtures screws a second time.

So what axactly is bench synchronizing?

[NICK!]

Hold the carbs up to the light and adjust the gap of the throttle plates by moving the sync screws until they all look the same. Helps get the regular sync done faster because they won't be so far off.

[fastpakr]

A small drill bit is helpful here to get them lined up more precisely.

[toymechanic.]

A small drill bit is helpful here to get them lined up more precisely.

Do you use the drill bit as a feeler gage?

[fastpakr]

Exactly. I should mention that I haven't actually done this myself, but I've heard others describe the procedure a number of times and it certainly sounds like the best way to do it short of a legit vacuum sync procedure.

[Hoomgar]

I'm not sure how the process is done on CV carbs but I know how to do it to VM carbs. Is the process similar? If so I can provide more info.

[bradleymaynar]

What Mark said!!

Brad tt

[Billy Ricks]

On CVs you're attempting to get all the throttle plates, butterflies to some, to have as close to the same opening as possible. A piece of light guage wire works good.

[DaveDanger]

My thoughts of a bench synch would begin with the drill bit gauge to mechanically set the throttle plates as close as possible, but would continue with a homebuilt "flow bench". Rig a bracket to rigidly mount the carbset in as close an approximation to the angle they normally sit on the engine. Cobble together whatever hose setup is possible, PVC pipe, or flexible air hoses, etc... to the engine side of all the carbs. Connect all these hoses to a shop vac. Have a "regulator pipe" in the shopvac hookup so that you can manually control the vacumn to a manageable amount. Connect your Motion-Pro® or whatever brand carb sync tool the way you normally would. Turn on the shopvac and synch to your heart's content. You'll still have to fine tune once it's all back on the bike, but you'll surely get it closer than any other method, and NOT have difficulties overheating the engine while you do it.

Caution** Make sure that you have the vacumn low enough that you don't instantly suck out the mercury in your sync tool. That's where the "regulator" comes into play. Basically a short (8") length of PVC pipe with 1/2" holes drilled all through it to allow an intentional leak. You simply tape up holes until you have sufficient vacumn to make the flowbench work. Begin with the sync tool connected and all the holes open (Very low vacumn), and tape one hole at a time till you have the vacumn you normally see on the sync tool.

[themess]

bench sync

Nice idea, Dave.

Suzuki recommends slightly different synchronization for 1-4 than for 2-3, with specific guidelines for their proprietary synchronization tool. Do you have any suggestions for getting the same result when not using the Suzuki tool?

Tom
GS850G '82

[DaveDanger]

As best I remember (At least the illustration shown in the Clymer manual) #1 & 4 cylinders are set about a half bubble higher than #2 & 3. That's doable with the bench setup just as easily. The nice thing about the flowbench is that it's dead steady... no vibration of bubbles and bubble shake from rpm variations and cylinder suction. Obviously when you reinstall it all back on the bike those factors will be reintroduced and you'll have to adjust for them, but it's usually a quick job after a good bench synch.

[toymechanic.]

As best I remember (At least the illustration shown in the Clymer manual) #1 & 4 cylinders are set about a half bubble higher than #2 & 3. That's doable with the bench setup just as easily. The nice thing about the flowbench is that it's dead steady... no vibration of bubbles and bubble shake from rpm variations and cylinder suction. Obviously when you reinstall it all back on the bike those factors will be reintroduced and you'll have to adjust for them, but it's usually a quick job after a good bench synch.

Dave,

The Suzuki sychro tool has calibration screws on it and the illistration in the Clymer manual tells you how to calibrate the tool, so in reality if you are using a Motion Pro non calibration type you would have 2&3 a half bubble higher than 1&4. Or that is how I'm reading the Clymer's manual.

Gary

[DaveDanger]

My memory may have fooled me. It's been a while since I saw the illustration. You may be exactly correct

[sharpy]

carbs

Instead of a drill i use the little plastic tube from a can of WD40 or simular