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Carb synchro tool review?

  • Thread starter Thread starter lurch12_2000
  • Start date Start date
L

lurch12_2000

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I searched the forum for some help on what others were using for synchronizing the carbs on my '83 GS1100G and found this:

http://i32.photobucket.com/albums/d44/rustybronco/vacuumgauge005.jpg

anybody used it?
Some questions are:
Where did you pick up the vacuum gauge? Max output reading? how much?
Size of the plastic tubing and how many feet total length cut into 5 pieces?
Does the green plastic valve unit have on/off valves so you check each carb seperately in consecutive order starting with carb #3? Any local stores have it? Get initial reading of all and then go back and start adjusting throttle doohickies?
Need four 6mm screw-in type connectors on intake boot for my model? Where are they available?
Should I expect readings around 15cm and try to make #2 and #3 carb(inside ones) a little lower?
thanks...
 
bout 114 USD...not bad considering the vaccum guages ive seen lately run about the same and you have to deal with the bouncing needle crap...That and a Colourtune plug will be my next tool purchases..
 
The performance/drag shop down the street wanted about 160 to do it, provided they had the adaptors. Im sure there are places that would do it a bit cheaper, but buying that tool would pay for itself in nearly one shot. You have to consider that if you are planning on rejetting or whatnot, you'll have to sync every time you adjust your needles, or change out jets. Unless you KNOW that what you've done jet and needle position wise is right on, i would purchase a tool.
 
I bought my carbtune for ?52 & have been balancing peoples carbs for years with it at between ?10 & ?20 a go which is far less than uk shops charge for the job

Minimum charge ive found in the uk is ?35 & some ripoff merchants want ?60 :shock: for what is sometimes 10 mins work
 
Exactly. they prey upon the uninitiated. I had never really synced em before Steve had brought his mercury sticks over and showed me how to do it, but after witnessing it first hand, i couldnt believe what these people wanted to do the job. And they're just SYNCING them, they're not tuning them. Buncha crap i say!
 
I don't think there is anything wrong with using one gauge with a switching port. Keep in mind that you are either going to have to make or purchase the port adaptors (not cheap when purchased seperately from someone like Motion Pro). In the end, some money can be saved but you are going to have to fuss around with the assembly.

I made two vacuum plentums, to damp needle fluctuation, and used them with two vacuum gauges to sync my 450. Worked fine. Fortunately, I already had the vacuum gauges so it didn't cost too much. Even still, by the time I purchased some sections of ABS for the plentums and some brass fittings and glue, I was almost half way towards some cheap mercury gauges (which I eventually purchased anyway). At any rate, nothing wrong with going cheap if that is what you want to do. It'll work which is the main thing.
 
TheCafeKid said:
........ You have to consider that if you are planning on rejetting or whatnot, you'll have to sync every time you adjust your needles, or change out jets. Unless you KNOW that what you've done jet and needle position wise is right on, i would purchase a tool.
Click to expand...

Not Quite. Syncing the carbs actually is adjusting the throttle plates to all be at the same angle. As long as the carbs are not removed from the rack, and nothing else disturbs their relationship the sync will hold. I've removed my carbs from the bike several times since my last sync. I've changed jets and needle pos. none of which affected the sync. As for the tools; I prefer merc. tubes, of which the morgan carbtune is topnotch. I have had excellent results with vac. gauges. Though they are a bit more cumbersome in action. The digital ones do not seem to be worth the money, as any of the name brands are $300 +.
 
Jd Powell said:
Not Quite. Syncing the carbs actually is adjusting the throttle plates to all be at the same angle. As long as the carbs are not removed from the rack, and nothing else disturbs their relationship the sync will hold. I've removed my carbs from the bike several times since my last sync. I've changed jets and needle pos. none of which affected the sync. As for the tools; I prefer merc. tubes, of which the morgan carbtune is topnotch. I have had excellent results with vac. gauges. Though they are a bit more cumbersome in action. The digital ones do not seem to be worth the money, as any of the name brands are $300 +.
Click to expand...
Well in my case i have to disassemble my slides to move my needles..in which case i would prefer to resync..
 
I just got and used the TwinMax electronic balancer for the first time. I can tell you it is simple to use, very accurate and no fluids to piddle with like MotionPro's or Carbtune's.

What I like is the fact that you balance each carb off of a reference carb (#3). Unlike the needle gauge type there isn't any fluctuations unless you want to take it up to that sensitivity. If you do it is still easy to see the difference between the two carbs as far as how much the needle bounces into each side of the scale.

For the best price out there go to RL Motorsports, $87.95.

TwinMax-thmb.jpg
 
Last edited:
I guess I got opinions on what type of synchro tool is preferred (not the one I showed) and that needle gauges have a tendency to jump around when measuring.

But some follow up on my other questions that weren't answered:
vacuum gauge for reading up to 30in (70cm) of vacuum and hose included is available at Sears for $20
pet store had 4 way valve with knobs for shutting airflow as needed to help stop needle jumping (as I understood from threads I researched) and measuring one carb at a time for $4 and package 8ft tubing for $2. I'm calculating that I'll need to cut into 4 2ft(approx) sections. May vary lengths from left to right carb as I think I would be on the right side of bike when testing.
still need hose adapters for screwing into the intake boots, 6mm for my GS1100G. any thoughts on these from bikebandit that you can leave on permanently with the rubber cap for $8?
http://www.bikebandit.com/product/1778
I think that would be everything for the homemade tester for a total of $34.
Again, what is the average vacuum reading everyone seems to be getting and happy with at 3k rpm?- 15cm for carbs 1 and 4 and 14cm for carbs 2 and 3?
 
RageZro said:
I just got and used the TwinMax electronic balancer for the first time. I can tell you it is simple to use, very accurate and no fluids to piddle with like MotionPro's or Carbtune's.

What I like is the fact that you balance each carb off of a reference carb (#1). Unlike the needle gauge type there isn't any fluctuations unless you want to take it up to that sensitivity. If you do it is still easy to see the difference between the two carbs as far as how much the needle bounces into each side of the scale.

For the best price out there go to RL Motorsports, $87.95.

TwinMax-thmb.jpg
Click to expand...



There are no fluids in the Carbtune... where did you get that idea? The silver parts you see are stainless steel rods, not mercury. The weight of the rods plus the inline restrictors ensure that the readings are very smooth, with no bouncing around.

With the Twinmax (on a four cylinder bike0) you still have to piddle around with switching between carbs and remembering readings. Seeing all four readings at once is a huge time-saver.

The Carbtune is the best bang for the buck by far. Easy, fast, and dead accurate.
 
TheCafeKid said:
Well in my case i have to disassemble my slides to move my needles..in which case i would prefer to resync..
Click to expand...

Are you running mech. slide carbs? (Identified by the throttle cable being directly connected to the slide via an actuating arm assemly.) Or are you useing CV carbs (these would be the BS series mikunis) CVs are identifyable by the round top which houses the diaphram. On these carbs the throttle cable actuates a row of butterfly valves.

I have the 34mm BS carbs on my current bike. I also have to dissasemble the slide to move the needle. This does not have any effect on the sync, as the throttle plates are not adjusted.

On the mech. slide carbs however, syncing adjusts the slide height so if you have to remove/dissasemble the actuating assembly to adjust the needle pos. I totaly agree with your decision to resync after. Please forgive my lack of foresight as to the differences between carb styles.
 
I am running mech carbs...VM26SS to be exact. No problem boyo, I wasnt sure on the CV's anyway as the one bike i have that uses them ive never had to adjust as of yet, so it was a learning experience for me anyway :)
 
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