Is it possible?

[shiznizbiz]

Is it possible to accurately vacuum synchronize my carbs with a singe vacuum gauge?
The reason i ask is that im a tad low on funds and i want to get my bike going before the weather gets icey. Im going to spring for the carb adjustment tool since the bench sync round shed light on how awesome this tool will be. The bench sync is done and is perfect.

[tkent02]

No, borrow one and do it right. There is a way they used to do on multi carburetor car engines, but I don't think it would work well with CV carbs, since they don't run well with the airbox off. Let the engine warm up and then let it idle, take a small hose, stick one end in your ear, the other into the intake air flow on each carb. Get the sound of air flowing in as even as you can between the four carbs. Like I said, I don't think it would work very well with CVs. Better to borrow the right tool.

[shiznizbiz]

LOL! im not sticking anything in these ears. I think i may have let the original post be misleading. Now that i re read that, i look stupid. lol
I was refering to hooking a vac gauge up to each of the sync ports one at a time workign my way from #3, #2, #1, #4. making sure that they get to the proper levels. I was going get 4 adapters of proper size with end caps so i could leave them in place while switching back and forth. I know it may take a little while, and wouldnt be as good as haveing 4 hooked up, but is it possible to get it close enough with out it beign too far off.

[tkent02]

Dunno how close you could get it, maybe better than the bench synch alone. They are interrelated, so changing one effects the others, but you may get it close enough to run OK. You could probably see if there was one cylinder way out from the others.
Let us know how it well you do.

[shiznizbiz]

cool. Nothing to it but to do it. I guess ill just give it a crack and report back.

[tkent02]

Sure, let us know. I am curious about it.

[Steve]

There have been several reports of home-made manometers, including one that used a single gauge and an aquarium manifold to switch between the carb sources. When you finally get to see all four vacuum readings at the same time and see how adjusting one carb affects the readings on all of them, you will see why it is an exercise in futility to use a single gauge.

Now, if you are VERY close to start with, you might get lucky.
I had the opportunity to verify the accuracy of a sync job with a single gauge.
It was remarkably close, but could have been better.

.

[BassCliff]

Hi,

Here's a simple 2 cylinder manometer:

http://www.powerchutes.com/manometer.asp

Links with 4 cylinder manometer info:

http://forums.sohc4.net/index.php?topic=23038.0

http://www.vfrdiscussion.com/forum/index.php/topic/16200-homemade-manometer/

http://www.youtube.com/watch?v=NqGsumK-mjI

If you Google it you'll find stuff all over the internet (or search this forum). I'm sure you'll get the idea. You would probably want to use a small reservoir at the bottom of the four tubes. Use tubes that are long enough so that the liquid does not get sucked into your engine. Use two stroke oil or ATF for the liquid just in case it does get sucked into your engine.

Thank you for your indulgence,

BassCliff

[shiznizbiz]

sweet!. yeah i may try one of those designs. they look as though they would work pretty well.

[Baatfam]

Your best bet would be to find a local GSR member or other multi-carbed motorcycle nut who has the proper tool and borrow it...

Maybe you would have to leave a little something as a deposit, or maybe not...
And maybe you could return it with a six pack of something good...
Or maybe they would just come over and help you...

Must be someone from here in your neck of the woods...

I know my carbtune came home with a sixer of 312 beer this summer...
(Thanks again Matt)

[mlinder]

It won't work. Whenever you make an adjustment to one, it affects the others.

[gearhead13]

I used a single automotive style vacuum gauge to sync a twin once. The one thing you need to do is put restictors in the vacuum line to even out the pulses, I used small beads stuffed in the lines

[Steve]

Shiznizbiz, you ready to do your carb sync?

I just noticed your location.

I will be coming through your area on Friday, November 19. If you are ready to do your carb sync, send me your address, I can stop by and sync your carbs for you. Yeah, I have my mercury sticks with me.

.

[shiznizbiz]

Sorry, Ive been away from my pc for the weekend.
I havent got to work on my bike much. I still have a couple of issues to chase down first before its ready for sync.
I have a climbing idle(possible airleak in the intake), and a lean condition in cylinders 1 and 2. so much so that the stock pipes are already blueing a bit after a few idle sessions. I cant nail down the air mix with the climbing idle, so thats first.
Combine that with my minor issues of exhaust not fitting down into the head right, (im thinking the after market crush gaskets may be an issue, double checking that in the a.m. too) and the dang choke lever assembly disintegrated on me because the cable was too long and met too much resistance.(duh) Thats being resolved soon enough. oh and i need to find a place local that has my air filter in stock. eh. its going to be a fun week.

[shiznizbiz]

Shiznizbiz, you ready to do your carb sync?

I just noticed your location.

I will be coming through your area on Friday, November 19. If you are ready to do your carb sync, send me your address, I can stop by and sync your carbs for you. Yeah, I have my mercury sticks with me.

.

Thats quite awesome of you. I read about good guys on here all the time...here's a prime example. This is how a strong community is built.
PM Sent