[Bryan Wilson]

I have ripples behin the side pipes (not as bad as yours) that were caused by the pipes getting to hot. I use to see the pipes glowing red at night. I cured the excessivly hot pipes by running more advance in the timing. With the advance to far retarded there is unburnt fuel getting into the pipes and burning in the pipes.I also found that having the explosion hapening inside the engine instead of in the pipes makes the pipes quieter and cooler and also a noticable increase in horsepower.
Cheers,
Bryan