synchronizing the carbs?

frickin_laser · July 28, 2005, 12:39:16 AM

Someone recently mentioned to me that you could synchronize the twin carbs on my 04 gs500f. I was told it would run and sound much smoother (less bbbrap! and more purr) if I did this. I'm not sure exactly how to do it-anyone ever done it themselves? Is it even woth the time?

StevenE · July 28, 2005, 02:02:32 AM

It's defenitely worth it. If you synch the carb, the vacuum in both carbs will be the same, resulting in the same mixture going in the 2 cilinders. A well synched carb make your engine pick up better, run smoother (less vibration) and will prolonge engine life.

I do it myself, but it recuires a manometer. I have the gauge types. There are handy guys on this forum who make there vacuum meters themself.

Jazzzzz · July 28, 2005, 02:59:10 AM

I tried making the $4 manometer via the procedure given in an old BMW K-bike newsgroup that I found via a Google search, but it did not work particularly well in my case. It's basically a long tube with some oil sucked into the middle of it - you connect each open end to the vacuum inlets on the top of your carbs and try to balance them by setting the vacuum so the oil level going to each leg of the tube is equal. Apparently the tube I used was a bit too short, because the oil was jumping all over the place going to each leg of the tube.

I wound up "balancing" the carbs by ear, adjusting until the engine was running the smoothest I could get it at 1750rpm, and I'm having it done at the shop when they put my bike on a dyno to get my last jetting kinks worked out for me. When it's cold, my bike still sounds like it has a lopey idle, and it will usually hitch once or twice during the first 30 seconds of being on choke. It costs less to have it done at the shop than it does to buy the few carb balancing tools I've seen for sale (they seem to run about $100 for one designed for a 4-cyl bike; I haven't found any specifically for twins).

Faxxxy · July 28, 2005, 03:54:14 AM

Don't buy the one with mercury...
Get the gauge type..

I bought the one with mercury and my roommate shattered it for me in the garage..

What do you do when 8 ounces of mercury hit the floor and scatter?

The Buddha · July 28, 2005, 07:41:42 AM

I do the thing wihtout a guage of any kind ... eyeball ... buttery smooth ... ask the ones that have sent it to me for jetting ... eyeball is best ... of course that means taking off the carbs ... maybe you dont wanna do that ... heck you do, jet it at the same time ...
Cool.
Srinath.

scratch · July 28, 2005, 07:57:27 AM

Quote from: FaxxxyDon't buy the one with mercury...
Get the gauge type..

I bought the one with mercury and my roommate shattered it for me in the garage..

What do you do when 8 ounces of mercury hit the floor and scatter?

You have to be verwy, vewry carefwul. eheheheh. (<-Elmer Fud impression)

I've had mine for 15 years. One thing you don't want to do is suck the mercury through the carbs when you chop the throttle (don't chop, roll off easy), it doesn't hurt anything...but the environment.

I'm thinking about having a Carb Synch Day at my house for everybody in the bay area...$2 donation and I'll have some hotdogs on the bbq.

Faxxxy · July 28, 2005, 08:14:15 AM

Quote from: scratchI'm thinking about having a Carb Synch Day at my house for everybody in the bay area...$2 donation and I'll have some hotdogs on the bbq.

That really is a testiment of how easy it is to do..
I had an old Goldwing that needed carb sync every 10,000 miles..

I got pretty good at it..

Mountaineer · July 28, 2005, 08:14:29 AM

With an almost-new '04, you can pretty much bet the carbs are in synch. There's not much that you could do to change it, short of taking them off and screwing around with them, with I highly un-recommend.

Faxxxy · July 28, 2005, 08:15:42 AM

+1

Don't screw with the carbs..
They will never work as good as they do from the factory..

The Buddha · July 28, 2005, 08:34:24 AM

Quote from: MountaineerWith an almost-new '04, you can pretty much bet the carbs are in synch. There's not much that you could do to change it, short of taking them off and screwing around with them, with I highly un-recommend.

OK you're joking ... right ...
Factory fitted and professional mechanics are the worst at slapping things that are waaaay off together and calling it good ... Learning while doing and taking the time to do it ... usually results in the best job ... This crap is simple enough that your possibility of screw up is sorta limited ... start running it like you are in a GP race to get most bikes out the door ... and even the experienced mech's start to lost it ...
Cool.
Srinath.

Mountaineer · July 28, 2005, 12:11:42 PM

Srinath, it seems to me that Suzuki has had enough experience with engineering the bikes (like nearly 30 years with the GS twin engine) that synching the carbs would be a real simple step before they're shipped. Your idea of synching by sight is one I followed with my old GS400, and I think it can work, but in my earlier days you had to have a special set of carb adaptors and the vacuum gauges, which I didn't want to spend the money on. It looks like Suzuki is building some excellent machines these days, it doesn't make much sense that the factory would compromise on something so simple and quick as synching the carbs.

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synchronizing the carbs?