Easy Home-Made Carb Sync Manometer

I had been trying to borrow a buddy's carb sticks for a while. When he finally recovered them from the last guy he loaned them to, they were no longer serviceable. So I decided to make the very simple manometer as detailed in other posts. It was so easy and seemed very precise. It cost me less than $5 for the clear vinyl tubing (the only item I didn't have on hand). I used some motor oil for the medium. Here is a picture of my rig in use.

This was such an easy procedure. I wish I had done this months ago. It sure smoothed-out the idle. I can't wait for my colortune to arrive so I can finish the job.

 

You don't need a Homemade manometer.
All you need is one Vacuum Gauge.
One.
You measure the Vacuum drawn on the Manifolds one at a time.
Mark the values with a small piece of tape indicator right on the face of the gauge.

Bring 4, 1 +2 to the same reading as you pull on 3.

Takes about 35-45 Minutes.
The Carbs get Synced.

Re-check the values to see that they are all the same when you do the last one.
They usually don't change if the rpm remains constant.

Old School.
Worked well back then ... still works fine today!

 

don't let rick make you feel like that was all unnecessary work... i still think its cool. Props for figuring something out!

 

Props.
Well done.

It's more important to get the bike Synced than it is to worry about how you go about doing it!

NO Offense!
Congratulations in order!

 

Bap,
That's the same kind I made and it works perfect. I actually made it for my V-twin (1100 Honda Shadow) but it ended up working perfect for both bikes. They are very sensitive and show every little movement when the bike is running. One of the best tools an owner can have. PD

 

Yep - I made one of those too. Cheapest and best carb sync tool EVER!

 

The only problem that I see with one monometer is syncing the carbs at anything other than idle. I synced my carbs at about 4000 rpm. With all four carbs hooked up it was easy. It is next to impossible to hold the rpm constant using the throttle. Trying to mover the monometer around, sync, and hold the same rpm would be tough

 

Why do you sync your carbs at 4K RPM?

 

I synced at 4K because I usually cruse at about that RPM. I know that syncing at 4K sitting still it is not the same as under load, but what’s the best way? I first synced at idle and then revved up 4k. Sync at idle was dead on but was not dead on at 4k. So I resynced at 4k. Which is better?

 

Sync at Idle.
Check for any variance at about 13-hundred.

If there is a substantial Variance at 13-hundred ... either Sync for 13-hundred or split the difference maintaining your good Idle.

The Carbs need to be in Sync at Idle and just coming Off-Idle when they start drawing on the Main Jet Flow.

Once you Open the Throttles and get into Mid-range ... it's the Sync you put on them at Idle that regulates the Main Jet Flow past the Butterfly anyway!

 

Someone once asked me why its called a Manometer. I didn't really know but replied, "Because when you see how well it works, you go 'Man O Man! This thing is great!'"