I've seen alot of posts about vacuum syncing the carbs.  Is there a FAQ anywhere on how this is done?  I recently rejetted, but didn't sync the carbs.  There did not seem to be anything in my service manual regarding this procedure.

I'm assuming this just consists of making sure the fuel levels in both carb bowls are equal?  Or am I wrong.  :dunno:

ASLAM.

Its a method to make sure the 2 butterflies open the same amount.
Vacuum method is sorta over rated... but doable. I eyeball synch them...
Take off the carbs and drain them... well you might want to drain the take off... Then from the airbox side look at the butterflies and lower the idle screw till you see just a thinnest sliver of light... Then adjust the synch screw till the slivers on both carbs are equal. That's it. The vacuum method... Have the tank off and get fuel to the carbs via a remote tank... I have a dirt bike radiator overflow tank I use for that purpose. The caps on vacuum spigots should be replaced by a clear plastic hose that fits tight on it. Then Toss them over the rafters and into a bottle of oil... yes you need 10-20 feet of hose. Then clip them with a adjustable clip. Start the bike and let it come to a steady idle... helps to start with a bike that's warmed up by riding... Then open the adjustable clip till oil gets sucked in but not wildly fluctuating. Then tweak the adjuster screw till they are equal height in both hoses. That's it. The eyeball method is pretty close and easier IMHO.
Cool.
Srinath.

is this hard to do for a mech. newbie?

Thanks scratch, does anyone have pictures of the screw on top of the throttle linkage?  I'm not sure about which one you're referring to adjusting.

Thanks again.

ASLAM.

Quote from: aslam[...] does anyone have pictures of the screw on top of the throttle linkage?  I'm not sure about which one you're referring to adjusting.

It's item #39 on the BikeBandit 1997 GS500E Carburetor diagram.

Quote from: aslamThanks scratch, does anyone have pictures of the screw on top of the throttle linkage?  I'm not sure about which one you're referring to adjusting.

Thanks again.

ASLAM.

Thank Srinath, too, he answered before I finished my book.

Note: balance screw = synch screw = screw on top of the throttle linkage

And you can use the tube method that Srinath described, too.

when do I have to sync my carbs?...my bike has 4000km on it

Quote from: Frostis this hard to do for a mech. newbie?

You have to be careful to not chop the throttle at high rpm's (or at all, be smooth with the throttle) or you'll suck in the fluid from the mercury sticks or the oil through the tubes, and through your motor (and mercury sounds really, really bad going through the cylinders). And squeezing your hand in between the gas tank (this is why it's easier to just leave the tank off and use a remote auxilliary tank) and adjusting the synch screw by feel (you can see it, but you should be lookin' at the carb sticks), without pressing too much on the throttle linkage causing the rpm's to rev up.

Quote from: Frostwhen do I have to sync my carbs?...my bike has 4000km on it

I suggest after every time you mess with the carbs or valves.

so at the 4000mi interval...when i should check the valves...i should also sync the carbs too??

how longs does it take to check valves and sync carbs for a TOTAL newbie?

Take a day. Just to be sure you have enough time, and to take your time, don't rush, you want to do a good job and not forget to do anything. It is very satisfying, at the end of the day, to have a smooth running machine.

O.k., timewise, I'll guesstimate it at 6 hours total, but that's not including lunch, breaks, oogling the shiney bits, or cleaning. :mrgreen:

Quote from: Frostso at the 4000mi interval...when i should check the valves...i should also sync the carbs too??

Sure thing.  The hard part (if you can call it hard) is getting/making the carb synch tool and auxiliary fuel tank.  Since the gas tank will be off for checking the valves, using the carb synch tool is very simple.

Quote from: Frosthow longs does it take to check valves and sync carbs for a TOTAL newbie?

Depending on how timid you are about "applying the wrench" (and whether you have the necessary tools handy), the first time through will take from 3 to ... 5? hours.  Or is that the 2nd time through...? :mrgreen:

HINTS

* Check the valves first, synch the carbs after.
* Consider applying some gasket sealer to the

TOP ONLY of the valve cover gasket when you reinstall it.  It will make it easier to remove & reinstall in the future.[/list:u]And now for some threads that may help with both jobs....

* Only useful if one or more valve clearances are out-of-spec:

DIY Tappet Decompressor? Is there anything like that..
* Aux. fuel tank picture, carb synch tool links: maintenance
* Where to hook up the carb synch tool: Carb synch[/list:u]

THANKS Kerry!

Long time ago I tried to synchronize with the clear tube and some oil in it. It didn't work because the vacuum switched very fast from one side to the other. The oil started foaming and got sucked into the carbs (hehe, huge plume of smoke :mrgreen: ).

So I tried another method. Remove one of the sparkplugwires and let it fire on ground. Now the engine runs on 1 cylinder. screw idle up until it's at 2000 rpm. Now let it run on the other cylinder. Adjust the rpm with the syncronizing tool a bit and then check how fast the other cylinder runs. Repeat until both cylinders run at the same idle-rpm.

Connect both sparkplugwires and reset idle-screw.

That's how I did it, and it seems to work because it's really smooth at all rpm's.

Quote from: LarsLong time ago I tried to synchronize with the clear tube and some oil in it. It didn't work because the vacuum switched very fast from one side to the other. The oil started foaming and got sucked into the carbs (hehe, huge plume of smoke :mrgreen: ).

So I tried another method. Remove one of the sparkplugwires and let it fire on ground. Now the engine runs on 1 cylinder. screw idle up until it's at 2000 rpm. Now let it run on the other cylinder. Adjust the rpm with the syncronizing tool a bit and then check how fast the other cylinder runs. Repeat until both cylinders run at the same idle-rpm.

Connect both sparkplugwires and reset idle-screw.

That's how I did it, and it seems to work because it's really smooth at all rpm's.

Oooo nice method... I'll try it next time. Just do it on a hot motor I guess.
Cool.
Srinath.

Sorry for newbie question but what a "syncronizing tool"

Quote from: alabrasaSorry for newbie question but what a "syncronizing tool"

It is a tool that helps you "balance" the carburetors so that they work together as well as possible.  Most work by comparing the strength of the vacuum generated by each carburetor.

For a couple of "real" carb synchronization tools, see the 7th and 8th items on Service Tools - Page 1 on the Motion Pro web site.  Don't buy a tool until you have compared prices at various online vendors.  For example, here are links to the

Motion Pro Economy Carburetor Tuners (which is the one I have)[/list:u]and

Motion Pro Mercury Carburetor Syncro Tuners[/list:u]on the Chaparral website.

Another type of carb sync uses dials with needles rather than columns of mercury.  For a few homemade carb synch tool ideas, check out the links I posted in my previous post in this thread.

If you still have specific questions, post them here.

Thanks Kerry...Lars made it sound like his method used something else in lieu of typical tool. I thought he had discovered a simpler method that didn't require carb tool. Darn!

Quote from: alabrasaLars made it sound like his method used something else in lieu of typical tool. I thought he had discovered a simpler method that didn't require carb tool.

Quote from: LarsRemove one of the sparkplugwires and let it fire on ground. Now the engine runs on 1 cylinder. screw idle up until it's at 2000 rpm. Now let it run on the other cylinder. Adjust the rpm with the syncronizing tool a bit and then check how fast the other cylinder runs. Repeat until both cylinders run at the same idle-rpm.

Sorry, alabrasa.  I didn't realize that Lars had used the term "syncronizing tool" that way.

Lars' method really IS "tool-less".  If the fuel tank is already removed, the only tool you should need for his method is a Phillips screwdriver.  Perhaps by "syncronizing tool" he meant the adjustment screw between the carbs. :dunno:  (See item 39 in this diagram.)