GoldenMotor.com Forum
General Category => Electric Motorcycle Conversion => Topic started by: Trials bike on June 14, 2018, 01:42:43 AM
-
Why can't I start a new topic?
I am wanting to convert my old gasgas trials bike into an electric bike and buy all the components from goldenmotor (looks like $2k worth of stuff) I am stumped on how to find an output shaft sprocket for the goldenmotor. Where are they sold? It needs to be a sprocket made for a 520 chain. How do the sprockets lock onto the shaft? I searched google for "electric motor sprocket for 520 chain "
Who sells these sprockets? Do they exist?
520 is the most common size chain for dirt bikes and trials bikes. Seems it should be easy to find them but its not.
-
Hi and(https://i.imgur.com/evDSMvT.png)to the forum.
Now that your account has been confirmed you should be able to start a new topic.
I think the internal diameter for the sprocket needs to be 7/8" (0.875" or 22.2mm) for the 5kW motor, and you'll need a pitch of 5/8" (0.625") to match your 520 chain. But you will need to use a sprocket with the least number of teeth to allow a reasonable gear reduction. An overall reduction of 10:1 will produce much better torque, but this would also reduce the top speed.
The sprockets are usually secured to the shaft with grub screws, but the correct sized drive key must also be used:
(https://i.imgur.com/ffvZZQU.png)
A 5/8" (0.625") pitch 10 tooth sprocket suitable for a 7/8" shaft should hopefully fit, but if the teeth are too wide for the chain to fit over, you may have to grind the outside of the teeth down (or use a wider chain).
A quick Google search returned this 10 tooth sprocket (https://www.rainbowprecisionproducts.com/50b10f-78-p-10250.html) which should be ideal, unless you can find one with fewer teeth. ;)
Finding a suitable 100 tooth rear sprocket to achieve the 10:1 gear ratio may be a bit more of a challenge. A two stage gear reduction using a jackshaft may be required to obtain a decent low gear ratio for increased torque.
Alan
P.S. Check out this post (https://goldenmotor.com/SMF/index.php?topic=6514.msg35867#msg35867) for further information.