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I have a set of 6 to sync the carbs on my CBX, they work well, you just need to balance them before each use. What are you asking ? How to use them or selling ?
 
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They will work, however, you should connect all 4 at once to a vacuum source, and verify they all read the same. Make any notes of differences, pick one as reference and mark the others with the discrepancy. In other words, you are verifying the calibration and will take any discrepancies into account when doing your sync.
 
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They will work, however, you should connect all 4 at once to a vacuum source, and verify they all read the same. Make any notes of differences, pick one as reference and mark the others with the discrepancy. In other words, you are verifying the calibration and will take any discrepancies into account when doing your sync.
That's true of ANY mechanical gauges. The mercury/other gauges are different.
 

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I was going to go this route with these gauge types. I read somewhere that the needle bounces because the vacuum is pulsing, and hard to get a measurement. Has anyone tried to use these type of gauges and has feedback. The fluid or mercury in the columns seems to buffer that effect, however I don`t always believe whats on the internet :)
 

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All types of vacuum gauges will bounce unless there are restrictors in the pipes to the gauges. In the first post, you can see the little white taps in the pipes, these are adjusted to reduce bounce.
 

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I was going to go this route with these gauge types. I read somewhere that the needle bounces because the vacuum is pulsing, and hard to get a measurement. Has anyone tried to use these type of gauges and has feedback. The fluid or mercury in the columns seems to buffer that effect, however I don`t always believe whats on the internet :)
I have used the mechanical gauges several time, and managed to get very stable readings by adjusting the restrictors. Super easy to do.
 

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These gauges are good for Synchronize Throttle Body?

Sorry my English
View attachment 82282 View attachment 82283
after an engine has been broken in / run in ( there are many POVs to how that process works effectively )

taking the time to ‘ Synch ‘ might result in smooth off idle operations

the gauges measure Vaccum at idle

a direct result of Intake resonances & exhaust reversions Effect IDLE Immensely !!!!

each cylinder is representaive of the mating of the valves & cylinder rings

if Uv done a cold compression check..........................NOT likely ALL cylinderrs read exactly the S A M E

over time of Normal running .......wear/tear U will find

ALL cylinders Do NOT Wear the same

so as U might replace plugs & adjust valves...............Ur ‘ Synch ‘ job will CHANGE

accordingly owing to many factors
 

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As I said above I have a set of 6 of these I use to sync the carbs on my cbx’s, they‘ve worked well for over 20yrs. to set them up you have to connect them all to a common vacuum source as Ray said above. If they read differently unscrew the lense off of them and use the silver screw on the face to adjust their reading until they’re all the same.
 
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As I said above I have a set of 6 of these I use to sync the carbs on my cbx’s, they‘ve worked well for over 20yrs. to set them up you have to connect them all to a common vacuum source as Ray said above. If they read differently unscrew the lense off of them and use the silver screw on the face to adjust their reading until they’re all the same.


how long time wise start to finish did it take to get ALL needles the same

ALL carbs

how often did U have to do them
 

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I sync the gauges before each use, I hook them all up to my MityVac hand vacuum pump through a multi tee I made up so they all see the same vacuum. The actual number is irrelevant just so they all read the same, once they are the same then I sync my carbs/throttle bodies. Setting them up usually is pretty easy & quick, depending on the day.
 

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I sync the gauges before each use, I hook them all up to my MityVac hand vacuum pump through a multi tee I made up so they all see the same vacuum. The actual number is irrelevant just so they all read the same, once they are the same then I sync my carbs/throttle bodies. Setting them up usually is pretty easy & quick, depending on the day.
I've always disagreed with this statement. For no other reason I guess that there is (and always has been) a specific number given in the FSM to set the vacuum to.
 

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Russ, I agree basically with you and you can set the gauges to any number you want So long as they’re all the same. The basic goal of syncing the carbs/throttle bodies is ultimately to make them all the same, so I don’t worry about the actual number, just make them all the same.

The most important thing about the gauges is that they are all the same linearly, so they all read the same at different vacuum loads. I do check mine at different levels & quite frankly they are better and more sensitive than my Carbtune which is ok but you really have to pay attention that the tubes are clean and move freely. I also check the Carbtune setup with my MityVac and manifold setup prior to use, it works well but is way more finicky.

Is there some benefit or result that I’m missing here ?
 

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I just follow the procedure in the FSM. It says to measure and if out of spec to adjust. The spec is specifically listed as shown below. Sounds like you're saying it will run with 1 inHg of vacuum just as well as 10", or 18", just so long as they're all the same. Sorry, I don't believe you. I adjust mine to meet the 2 conditions pictured.

Rectangle Organism Font Slope Parallel
 

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So let me ask,, how do you increase or decrease the engines vacuum? What I’m saying is no matter what the actual engine vacuum is that if you set the gauges up to read the same on the work bench and then attach them to the vacuum ports and then adjust the throttle bodies to read the same across the board you will have sync’d your throttle bodies. On my fjr depending on the day I see between10-12 inHg at the gauges, is that the actual vacuum ? Don’t know w/o actually calibrating the gauges on a master gage. I guess I’m not sure of what you are trying to tell me.

So do you just take your gauges off the bench put them on your bike and just adjust the throttle body vacuum to 9.8inHg across the board ? what about the “master” #3 t-body ? What gauges do you use ? Just tryin to understand here.
 
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