It might be worthwhile reading up on pipe tuning. Macs website has a good article on it.

I don't have a lot of experience with pipes yet, but I used the can from the MVVS 49 conected to a macs header pipe with great results on a GMS 47 recently. The header pipe comes a little longer than you will need. You tune it by cutting the header 1/4 inch at a time and measure peek RPM. the first couple times i cut it i got 300 RPM more, then 200, then only 100 more, so i figured i was close and left it alone. the throtle responce is outstanding and the needle settings are not sensitive. The length between the ehaust port and the expansion chamber is pretty critical, so if the guy insists you need a different pipe he might not just be trying to get into your wallet. The header pipe you have might be too short.

A lot of folks are playing with Mousecan pipes now. You start with a macs header (20$) and add an empty mouse can, spend a few minutes tuning it, and viola! you have a screaming beast ready to leap off the ground and rip up some sky! they almost always provide great midrange too. It is a little work but worth the effort.


Bob is right about CG. very important for flat spins. tiny bit too forward and you never get the tail down, tiny bit too far back and you have trouble getting out of the spin. the little tweeks can change a boring plane into a beast

hang in there