Gearing Advice

[70ccswag]

I'm looking to switch gearing to gain some top speed.

I have a 70cc malossi iron, 19mm Delly carb, hoca var. and clutch with 2k springs, 1k contra (too low I know, but checking top speed), and I finally got it running right. After the initial bog from the light contra it pulls from ~5mph to 54.2mph (GPS) at 10.4k rpm (tach). I have a strada rx8i (keeway matrix 50) minarelli clone with the larger crank shaft output.

Does anyone have any suggestions as to what gears will accomplish this?

Much appreciated

[90GTVert]

Check your gears to see where you are now before you decide on anything.

If your current bog is below 5MPH, it's probably not the contra. It's more likely to be an issue with the clutch springs or the belt not being in a good "first gear" position (low in the front pulley, high in the rear pulley).

[stepthrutuner]

My thinking is to go around 10% longer gears. That's a 1000 rpm drop roughly and keeps you in your power band. If you have hills you will regret going much longer. Besides that, you're probably pretty close to being drag-limited (I assume you were sitting up?) so even optimal longer gearing might only be able to eek out 60 mph.

Man, put that stiffer contra in. That spurt away from stops is what it's all about as far as having a neat little traffic weapon goes. :thumb: