so I got an urban engine from Jimmy C. thanks JC. It's an Iowa version. With an MLM pipe and some variator tuning, I got it up to 37 mph. BX31 (didn't have an extra Malossi belt handy), 33 grams, gy6 clutch, yellow springs, grey contra (1600 rpm). Also has an SHA clone carb.
Anyhow, we always want more and I had the Malossi roller gears in a drawer screaming to let them out in the light of day. After staging a fight between the gears and myself armed with a 3 jaw puller, a toaster oven, freezer, and a 2x4, I got the old ones off and the new ones on and avoided any trip to the emergency room.
Anyhow, the new gears didn't do poop with the current set up - although I changed it slightly and lowered the weights to 27 grams - a mistake. Tried 30 grams with an ax31 belt - no help. So I put in red springs, 33 grams, the bx31 back on with a spacer and will test that soon. in the back of my mind is that this stock Iowa engine just can't turn those gears.
there's a DR kit in a drawer screaming somewhere. Confirm, deny, otherwise?