Carb Synchronization !

[giraffe]

Where can I find some information on synchronizing the carbs on the GS500 ? I remember seeing a simple way of doing it on a BMW website using a heavy-oil and a clear tube ..

I can't even find the synchronization screw !

[KevinC]

There is an article on building a $4 carb balancer at:

http://www.airheads.org/index.php?Technical%20Tips+%244%20Carburetor%20Synchronizer

I have a different version, with an aquarium needle valve between the two legs at the top of the "U". By adjusting the valve, you can gradually adjust the sensitivity from zero (valve open), to very sensitive as you get the carbs tuned in. This allows you to use a very short U ( i think mine is baout 12" high), and I just use colored water for a fluid. It works very well.

The synch screw is between the two carbs on the throttle linkage. It adjusts the angle of the butterlies relative to each other, so there is only one screw required.

[tiedyeguy]

This brings a question to mind...does anyone know what a carb synch guage set goes for?  Eventually, i should buy one...

[Black Snowman]

Cheapest I've seen a ballance gauge set (4 dial vaccuum gauges on a board) is about $60. Can't remember where off hand but they're out there.

[Kerry]

MotionPro makes a pair of mercury stick gauges.  Go about 2/3 of the way down the Service Tools - Page 1 page on their site for info.

Chaparral Motorsports offers the Econo version -- the one I bought -- for $35.99 and the Pro version for $64.99.  (Search for part numbers 315-0437 and 315-0440 respectively.)

[tiedyeguy]

Thanks for the help. ordering one from chaperal.

[dond6]

JC Whitney has one for $39.99. Mercury Synchronizer,
Part # AGB063198T

[Mizen]

My bike is in dire (I think) need of a carb-sync, it is running hella rough and I can't find any other problems with filters/lines/plugs/gas etc.... A synch has not been done for 25k miles (I know, I know....)

Anyway, my Haynes manual doesn't have diddly-freakin'-squat about this procedure, so I'm unsure about how to proceed.  I have a set of carb sticks on the way, but I don't know where to hook them up to, or what the nominal factory recommended vacuum level is (or whatever the sticks measure)....

I can probably find the butterfly adjust screw.  Is there anything else I need or should do.... :dunno: ?

Any help is appreciated guys and gals!  Thanks,
Matt

[Kerry]

Mizen,

I went back and found that you have a '91, so here is the matching diagram for your carb setup:

'91 Carburetor diagram from BikeBandit.com

To synchronize the carbs, attach the vacuum lines to the vacuum takeoff (#8 ) on each carburetor.  Obviously, you must first remove the clip (#15) and vacuum cap (#14) from each carb.

The only adjustment you make is to the screw (#50) between the carbs.  There is no set amount of vacuum - you just want to get the two levels as close to each other as possible.

Good Luck!

[Maniac]

This sounds disturbingly easy...  

I've always heard that syncing carbs was a royal pain in the butt. Is the GS just that much easier to work on?

[Wrencher]

Carb Sync'ing isn't that difficult, its just a tedious process. Harleys and singles are easy, one carb= nothing to sync. Twin carbs are pretty basic, as described above. The PITA part comes from doing that with a bank of 4 carbs on a CBR, Gixxer, etc. The ENOURMOUS PITA part is on bikes like Honda Valkyrie with 6 carbs. Lots of fun.

[Kerry]

Anyway, my Haynes manual doesn't have diddly-freakin'-squat about this procedure, so I'm unsure about how to proceed

I just noticed this part of your post.  Do we have the same Haynes manual?  ('89 - '97)

My manual devotes almost a whole page to the procedure, including two pictures.  It's in Chapter 1, section 25.  (Page 1.18 )

[Mizen]

Fantastico!  Thanks for the input Kerry.  I have a haynes manual 89-96.... maybe my mistake was expecting the info in the carburator section, pages 2xx something.... Boy would I feel stupid if it was in there.... :lol:

Can't wait to have this done soon.  Being on a crappy running bike is no fun!

[JLKasper]

I have a different version, with an aquarium needle valve between the two legs at the top of the "U". By adjusting the valve, you can gradually adjust the sensitivity from zero (valve open), to very sensitive as you get the carbs tuned in. This allows you to use a very short U ( i think mine is baout 12" high), and I just use colored water for a fluid. It works very well.

     
That addition of that "aquarium needle valve" sounds like the dog's hangers.  Where might one pick up such an item (I'm assuming a pet store that specializes in tropical fish), and would the clerk look at you crosseyed if you asked for it?  What size tubing do you use, and I'm guessing a couple of tees are also involved?  

[yamahonkawazuki]

aaaah, the cbx is satans spawn :x   whoa, i just looked at my post counter :dunno:

[Kerry]

[...] "aquarium needle valve" [...] I'm guessing a couple of tees are also involved?

Right you are.  For a picture, check out the old thread My $5 carb balancer...

[JLKasper]

Thanks, Kerry!

I had links to a $1.55 and $4.00 carb synchronizer, but not to KevinC's.  I think I'll splurge for the fiver.  It looks like a dandy, and won't take up as much space in the toolroom.    

<<the symbol of perfectly synchronized carburetors!