Originally Posted by cannonball2
You have a good eye on the fenders. Had to make two small extensions the extend the rear fender to get the proper spacing. Details details.
A common CG sprocket will bolt directly to an 18t sprocket on an IGH or coaster, aligns easily and runs very true.
The BB mod is just flange bearings bolted to the BB. The clutch is a 12t, mainly because I screwed up and ordered that instead of the 11t I wanted. It runs to a 28T which I had on hand. This also keeps the sprocket size small for clearance. These are #35 chain. This gets the most teeth in the smallest overall size.
The secondary side is a 9t to a 44t running a BMX chain. This gives an 11.41 overall ratio. The 3speed Nexus takes this ratio to a 15:1 for low and an 8:1 for 3rd. 2nd is direct drive at the 11:41. This gives a top speed around 43mph should I want twist the engine to 4750rpm which a stocker will do no problem.
I just put a newer used Briggs 3.5hp 9000 series in place of a Briggs 3hp 8000 series that was worn out.
I like riding with more torque, I'm only legal on trails no pedals any more. I had 20:1 ratio with 26 wheel no shift gears. It was good.
Now for how I had to fit the newer used engine I have only 13:1 ratio.
As an option I may get 14:1 ratio, but I'll have to do as mentioned below.
Option is to be using the engine to drive a jack shaft with the clutch on it with a reduction of 1.08 : 1
Then the auto clutch will not engage at 2000 to 2200 rpm ting the bell of the clutch to fully lock, nope ting the bell to lock up will be at 2167 to 2367 rpm.
Either way I was wondering how in comparison does your bike with 3 speeds do with the similar engine on hills?