Motorcycle Repair: Knocking, suzuki 1200s bandit, auxillary fuel tank

Question
I have an 03 Suzuki 1200s Bandit with 1756 miles on it. I have noticed a knocking noise that seems to be coming from the gas tank (I know that sounds strange). It only occurs when I go from higher (3k - 6k) Rpms to idle(1200 rpms). An example would be cruising along at 60 mph and then coming to a stop light. The knocking will occur for a couple of seconds then fade off then occur about a second then go away. When investigating the noise off the bike, the loudest I hear it is around the lower portion of the gas tank. I have used 87 - 92 octane and it still persist. The bike was taken in for its 600 mile service at the dealer and has never been above 7000 rpms or abused in any way (I'm 42 and ride conservativly).

Thanks - Tony  

Answer
Hi Tony,

It's impossible for me to diagnsose sounds accurately without being present.

I recommend having a local tech ivestigate the sounds for you.

If you want to investigate further, remove the tank, plug vacuum lines, and start the engine. Listen for the sound using a mechanic's stethoscope. The engine should run for about five minutes on the fuel in the carbs.

If necessary, connect an auxillary fuel tank. Place a fan in front of the engine.

Visit: "www.banditalley.com" and "www.gixxer.com" Both are good resources.

Respectfully,
Mark Shively