Motorcycle Repair: Suzuki GS 650L, suzuki gs, starter fluid

Question
Dear Mark,
I could really use some advice. I recently picked up a 1982 Suzuki GS 650L and the idle is very erratic.

A shot of starter fluid gets it going and then I adjust the throttle to around 1.75 rpm. It idles consistently until I start out. With each up shift up and then return to neutral the idle increases. After ten minutes of riding the idle is around 4 to 6 thousand RPM's. In order to get it home I adjust the throttle cable tension each time I  stop. Now its safely stored and I need to start looking for a better solution.

The bike had been sitting for awhile but the seller assured me it was in "good running condition" It may have been, but its not now. I have a couple of ideas but no real experience. First, he added a secondary petcock because the first one was leaking in the off position. I can see nothing leaking, but what should I be looking for when going over the fuel system? I'm also thinking the carbs need cleaning but don't want to get in there if I don't have to. What simple solutions should I try before any major work?  

I really appreciate your advice,

Dan

Answer
Hi Dan,

I suspect the carburetors need thoroughly cleaned to remove varnishing left by the old gas in the float bowls.

You've described symptoms of an intake air-leak, too. Erratic idle is indicative of this, but so is unbalanced carb synchronization.

AIR-LEAK CHECK: Spray brake cleaner or carb cleaner around the carbs and rubber intake manifolds. Brake cleaner will make engine rpm bogg. Carb cleaner will make engine rpm rise. Use one or the other. Carb cleaners are more flamable than brake cleaners. Perform test with cool engine.

If no leaks are found, clean and synchronize the carbs. I think you'll correct the problem.

I return repair information files by email. You did not include your email with this question as requested. If you want this detailed how to info, email me:

mshively1@woh.rr.com

Visit: "www.bikebandit.com" and click on "OEM Parts" when site opens. Select your MC from the menus that appear. See exploded views of the carburetors, etc... here.  

If you experience electrical or charging system problems, visit: www.electrexusa.com for replacement parts. AVOID Suzuki's stock parts. Suzuki GS Series MC charging systems have a design flaw and are destined to fail. Electrex USA manufactures high quality components designed by them to correct the Suzuki GS design flaw. To learn more about this and other GS related intel, visit: www.thegsresources.com

Respectfully,
Mark Shively
Dayton, Ohio