crf50 4 speed transmission upgrade????

[crazycableguy]

my bike is an urban cruiser wheelie bike. I dont have enough top speed and dont want to change the sprocket size due to the loss of torque.

I would like to keep my gearing the same but simply add a fourth gear....

Enter the ebay search....

I found a 1 down 3up gear set for the 50's made by ahp. $150.00

it has the following ratios:

Primary reduction ratio: 3.722 Gear Ratio: 1 - 3.182 2 - 1.706 3 - 1.238 4 - 0.917

(stock 1st gear: 3.272)

(stock 2nd gear: 1.666)

(stock 3rd gear: 1.190)

does anyone have any experience/insight with this or any aftermarket transmission gearing?

Thanks-

[qwoke-q]

Well, if you want to add a 4th gear and keep the first 3 ratios, then essentially you will be losing torque in 4th gear. So you could get the same result for the price of a sprocket. Or you could buy the AHP 4 speed, or a 4 speed from another Honda bike. As far as I know, there is no 4 speed with the same first 3 ratios as the Honda 3 speed.

[T Bolt USA]

we have the same kit ,good set up for mildly built 50 motors

[crazycableguy]

thanks for the info qwoke-q...

my main purpose in the transmission upgrade it to go faster than my friend top speed, but I dont want to loose them off the line.

to keep close to my current gearing could I go with the above upgrade and then drop a few teeth on the rear sprocket?

[qwoke-q]

If you keep your current gearing, you will not gain or lose any speed or torque. But you will have to shift one more time and essentially you will have paid $150 and not gained performance.