HI Mugenkidd,What I do to the rossi's to make them run are two things,lower the compression if you run nitro,two,three or four head shims,They have to much compression but they run fine on no nitro.With no nitro I use one to two head shims,mainy one shim.Now the carb I sharpen the low end needle becouse you can not fine tune the bottom end becouse it is ether rich or lean.Once you fix the needle the carb will not load up or lean out on take off.On the one I worked on I opened up the end(output) of the tuned pipe to 1/2" I.D. the engine did not over heat and carb tuned. better and the engine hit 23k rpm's.I found this out about the pipe from running the K&B100,temp was 358deg's and then i opened up the tuner pipe at the end(cut the stinger off) and engine ran at 256deg's and stoped blowing out the couplers and ran like A top! Take care-Mac