ive heard in the edge its because the fan air intake is so close to the exhaust the engine is really hot all the time...wiesco pistons a little rich jetting and turned up oil pump should get you by with out problems
The 550 is a gutless fuel hungry engine that is almost impossible to be a "finely tuned" performance fanner. A yamaha 485 Phazer had twice the "Nut" than a 550 Poo. But, jetting it down and wrapping the pipe will help a bit.
Rot.