What are the symptoms of the carbs being out of sync?

[MVent03]

2009 GS500F 15,800 miles

I suspect that my carbs need some maintenance.

Idles high(1500RPM) after prolonged highway riding.

Loud POPS if I blip the throttle at a stop. (Not a backfire I don't think but it's more than just a decelleration pop)

Seems sluggish off the line and occasionally at highway speeds. (The colder it is the better my bike seems to do on top end.)

I've never checked valve clearances either. I tried once but it was more than I wanted to get into at the time.

Any thoughts?

[ThatOtherGuy]

Don't discount a batch of bad fuel.  I had just serviced both my bikes (GS500 and Bandit), balancing carbs etc and both were afflicted with similar issues to what you describe.  Fuel treatments and a carb clean later running out the bad fuel replaced with good and they are finally running properly again.  You may still need a carb sync, but try getting rid of the fuel and replace with a good source (with a petrol treatment and fuel system cleaner) first.  It may take a long ride to run out all the fuel and clean the system.

[weedahoe]

It's my opinion that if you think they are out of sync, why not go ahead and sync them. At least rule it out and do maintenance at the same time

[craigs449]

check your valve clearance!  should be done at least once a year!  the rest of the bike will not run right until the valves are in spec. get them in check and then worry about syncing the carbs........

[jestercinti]

Valves first, everything else later.

[Suzuki Stevo]

To answer the original question..."What are the symptoms of the carbs being out of sync?"
Stumbling or any kind of hesitation coming off of an idle, and I'm talking about the first 1/32 of rotation. Syncing/balancing makes your carbs work as a team as you transition off an idle. Syncing at an idle is fine and there isn't any reason to sync at any Rpm higher than 1,500 Rpm. The farther you get from an idle the less syncing comes into play 

And yes, any and all valve clearance issues/maintenance should be done before you sync. That's not done to rule out valve clearance as a potential problem, it's that changing the valve clearance will alter the sync by changing the engines flow, so it's valve clearance before a sync...basically don't bother doing a sync if your going to adjust the valves soon.
*For a carb sync* Make sure your engine is up to temp and you have an uninterrupted supply of gas. I have been syncing carbs/TB's with the same manometer since 1979, I have bought more than one bike that needed the carbs balanced as soon as I got it home from the dealer.

   

[MVent03]

Alright, looks like I know what I'm doing Monday then. If I should need to make adjustments, shim it if I remember correctly, can I get an assortment of sizes from a Suzuki dealer?

[jestercinti]

You should be able to get shims from the dealer.  That's the fastest way since online takes a week for shipping.

[craigs449]

to clarify suzuki steve's posting above, the bike should be fully warmed up for CARB SYNC, and completely cold for VALVE CHECK......

[Suzuki Stevo]

to clarify suzuki steve's posting above, the bike should be fully warmed up for CARB SYNC, and completely cold for VALVE CHECK......

Yeah...I do kinda jump back and forth on that