Motorcycle Repair: 1989 GSXR-750, suzuki gsxr 750, gsxr 750 1989

Question
1989 Suzuki GSXR-750, jetted, K&N air filter, vance and hines pipe.

I purchased this bike in late fall 1999. I was told the valves had just been adjusted then.  All modifications were done before I purchased the bike.  (Yes, the Vance and hines pipe makes noise from hell!)Since then I have put about 2500 miles on it, overall 23000 miles total on odometer.  

This season the bike doesn't want to idle properly.  I replaced all the plugs.  When I rechecked the plugs #3 cyclinder was fouled with carbon all over insulater and tip. Replaced it and verified I was getting fire from the plug.  All other plugs checked out OK.

Is my problem the carburetor? or valves?  

If carburetor, is there an easy fix, without a major overhaul on the carburetor(s)?  Is there a needle valve that is clogged I can adjust without screwing up the syncrinization of the 4 carbs?

Thanks for any help you can give...-Jerry

Answer
Hi Jerry,

Send me an email address as requested. I'll return repair information files to explain in detail carb tuning, cleaning, and synchronizing.

Valve clearances must be within specs before synchronizing carbs.

I suspect a bit of varnishing may be present causing some problems. Send to me here: mshively1@woh.rr.com

Respectfully,
Mark Shively