A little something I've been saving...."A stock motor on methanol responds best to stock type pipes with stingers. We have a pipe we call a Q-98 that should work well. Because of the cooling effects of methanol a general rule of thumb is to run the head pipe length 1/4" shorter than when running gas. A choice you would have with this pipe would be using a 1-3/4" or a 1-7/8" header. My recommendation would be a 1-7/8" header with a head pipe length of 9-1/8". As far as gear the pipe won't perform well trying to make it LUG. It works best when it gets off the clutch quickly and pulls through the power band. A good starting point would be...... With the the clutch engagement at 10,500, gear it to top rpm's in the 14800 to 15200 range.
This setup on a stock motor wont make quite as much peak power as an open 100cc. But the power band will be much wider, simpler to dial in, and should be quite competitive on most tracks."
Hope this helps. Kermit Buller