TBS synch tools

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wel1123

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It's time to buy a Throttle body Synch gauge or mercury manometer for my 07 FJR ( don't trust anybody to do anything on everything I own). Whats everyones thoughts on a good buy for a good tool? I used borrowed gauges in the past with fair results but need to buy my own now.

 
I originally bought the Motion Pro Economy (mercury). Recently purchased the CarbMate electronic after a garage gremlin cracked one of the tubes on the mercury gauge. It still works, but I thought it only a matter of time before it fails.

You have to learn the CarbMate. I also purchased the four cylinder adapter that is basically a set of petcocks that allows you to open one cylinder at a time to the gauge. The CarbMate does NOT give any values. It allows you to zero a reference signal on one cylinder, and then match other cylinders to that one via its second input.

The CarbMate takes a little getting used to, but once you spend a few minutes learning how to compare (3 to 4),(3 to 2),(3 to 1), and then (1 to 4), it works extremely well. You can also watch the flashing pattern of the LEDs to get both cylinders being tested to "look" exactly the same. I followed up behind the CarbMate TBS with the mercury gauge. The CarbMate is supposed to be 0.5 accurate and I found that by matching the visual flashing patterns of the LEDs, that the mercury gauge showed identical matches. The CarbMate was much more accurate than I could ever achieve with the mercury gauge. You just don't know what the actual vacuum value is. You can only match the cylinders to each other.

The CarbMate also does not work for off-idle or higher RPM matching. I assume because the pulsing of the vacuum values is not significant enough to trigger its LEDs.

 
How about the Morgan CarbTune? I was looking into one of those and it seems to get pretty decent reviews.

 
I bought a Motion Pro mercury Carb Styx several years ago when I had a CBX. It works well and I used it to check my FJR throttle body synchronization.

However, some recent reading regarding mercury toxicity has convinced me that mercury really is some bad stuff for your health! Particularly mercury vapor, which is created in abundance when used in a manometer type setup as a Carb Styx. I'm inclined to stay away from using it any more.

When I checked the Motion Pro website last week, they appear to have discontinued selling the Carb Styx, and now only offer the electronic gage sets.

Last time I looked JC Whitney had a fairly inexpensive gage set too.

 
used Motion Pro economy from Rad-Mart. Best 25 bucks I've spent in a while. Drop him a PM. I believe he still has one more.

 
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I have a TwinMax, but don't know if it's a good idea to use it in a 4-cyl bike, since I'd have to do 2 at a time. Maybe the error keeps compounding, no? I could always check other 2 to see if they're the same.

Hey, question: for those doing their '07s; WERE THEY OFF? I was planning on doing it on my brand new '07 only if they have been off before. Thanks.

JC

 
I have a TwinMax, but don't know if it's a good idea to use it in a 4-cyl bike, since I'd have to do 2 at a time. Maybe the error keeps compounding, no? I could always check other 2 to see if they're the same.
Hey, question: for those doing their '07s; WERE THEY OFF? I was planning on doing it on my brand new '07 only if they have been off before. Thanks.

JC
Do it!

 
I have a TwinMax, but don't know if it's a good idea to use it in a 4-cyl bike, since I'd have to do 2 at a time. Maybe the error keeps compounding, no? I could always check other 2 to see if they're the same.
I use a TwinMax too. There is nothing wrong with doing it two at a time. Most bikes have a cylinder specified as the one to match to in the service manual. It's #3 for GenII FJR's and probably the same for Gen I's. The only problem I see with it is poping those caps off and on. I'm going to an aquarium store and get a three or four gang air valve so I can run #3 to the TwinMax and the other three to the valve. That way I can just turn on one cylinder at a time to match and go back and recheck them when I think I have a good balance. I've used it already on my 06 with excellent results.

 
Hey, question: for those doing their '07s; WERE THEY OFF? I was planning on doing it on my brand new '07 only if they have been off before. Thanks.JC
Unless your atmospheric conditions are extremely close to those at the factory in Japan, (at the time the TBS was done there) then you'll probably see some variation between cylinders.

Also factor in variables beyond that - are you adjusting at idle, cruising RPM, airscrew adjustment VS throttlebodies, blah blah blah.

You can find imperfections in anything, it's just a matter of how powerful a microscope you use. Based on what I've seen posted by others, my impression is that some dealers will shine this on unless you're standing there while they do it.

 
I have a TwinMax, but don't know if it's a good idea to use it in a 4-cyl bike, since I'd have to do 2 at a time. Maybe the error keeps compounding, no? I could always check other 2 to see if they're the same.
I use a TwinMax too. There is nothing wrong with doing it two at a time. Most bikes have a cylinder specified as the one to match to in the service manual. It's #3 for GenII FJR's and probably the same for Gen I's. The only problem I see with it is poping those caps off and on. I'm going to an aquarium store and get a three or four gang air valve so I can run #3 to the TwinMax and the other three to the valve. That way I can just turn on one cylinder at a time to match and go back and recheck them when I think I have a good balance. I've used it already on my 06 with excellent results.
I use a Twin Max on my Beemer twin. Don't you have to make sure that both vacuum lines from the Twin Max have EXACTLY (as close as possible) the same length to the the TB's? Just wondering.

-Sirby :blink:

 
A friend gave me his carb sync gauge set

https://www.jcwhitney.com/Motorcycle-Fuel-S...s/600014252.jcw

and it works for me. comes w/vac line snubbers (for less gauge bounce)and ea gauge is adjustable and also comes with verious adaptors (fits the FJR) & hoses. I use my Mityvac gauge to "zero" ea gauge in the center of their range. It doesn't matter what they read, just as long as each read the same as the others. Adjusted this way, only one of my gauges is slightly off at 0 inches...Later,,,De :rolleyes:

 
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I also have a Twinmax, a great tool, from my beemer twin days. It always worked like a champ there, but like a differential manometer, it does not give you an absolute vacuum measurement, only relative.

So technically you still need a vacuum gauge tool of some kind in order to do a full TBS. That's just so that you can set the #3 absolute vacuum to spec (9.1" Hg.) and then adjust the other 3 to match. You are then supposed to insure that they are all still at ~9.1" at idle speed

Factoid for the truly frugal: 9.1" of mercury = 133" (11' 1") of H2O. If you wanted to calibrate a manometer to use an unknown, more viscous fluid (like ATF) you could use a variable vacuum source (such as a MityVac) on a Tee connector and two manometer tubes to calculate the fluid's vacuum scale ratio.

1" of mercury = 13.6" of water.

Here's a neat link for vacuum units conversions: https://www.brandtech.com/vac_unit.asp

 
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