mattg37
1 mW
- Joined
- Jul 1, 2020
- Messages
- 11
Im trying to convert a Honda CRF250 to electric as my first electric bike project. i plan to do some posts on the build as it hopefully progresses..
so far i have :
CRF250 2005 rolling chassis that i got for £500
QS 138 90H 4kw motor
VOTOL EM200 cost of motor/controller/throttle/wiring £800 after duty etc
22s2p AIG lipo cells with 300amp BMS cost about £600
ive bench tested the electrics and can get the sprocket turning(fast) even with the $10 QS throttle !
my main concern is GEARING ?
ive read loads of threads of some amazing builds and it seems like 8:1 reduction is the right choice?
i really dont want a noisy jackshaft so am going to try direct drive as its way easier
the motor comes with a 428/14T sprocket so has anyone found a solution for fitting a 10 or 11 t on the tapered motor shaft?
i cant find the details of the taper and key
the rear sprocket needs to be a 428/80t plate sprocket which is big but not ridiculous at 335mm diameter
my local laser cutter can only make one if i supply the material and a cad file ... has anyone already done this ?
for refence the CRF fitment is a 125mm diameter hole and 6 x 8.5mm counter sunk holes on a 154mm PCD
the standard 51T 520 sprocket is 270mm diameter
plus it would need some larger holes ffor weight reduction while retaining strength and looking finished
ive heard water jet cutting distorts the finished product
any advice on bespoke sprockets would be greatly appreciated
i hope my information is of some help to the community
thanks in advance
Matt (uk)
so far i have :
CRF250 2005 rolling chassis that i got for £500
QS 138 90H 4kw motor
VOTOL EM200 cost of motor/controller/throttle/wiring £800 after duty etc
22s2p AIG lipo cells with 300amp BMS cost about £600
ive bench tested the electrics and can get the sprocket turning(fast) even with the $10 QS throttle !
my main concern is GEARING ?
ive read loads of threads of some amazing builds and it seems like 8:1 reduction is the right choice?
i really dont want a noisy jackshaft so am going to try direct drive as its way easier
the motor comes with a 428/14T sprocket so has anyone found a solution for fitting a 10 or 11 t on the tapered motor shaft?
i cant find the details of the taper and key
the rear sprocket needs to be a 428/80t plate sprocket which is big but not ridiculous at 335mm diameter
my local laser cutter can only make one if i supply the material and a cad file ... has anyone already done this ?
for refence the CRF fitment is a 125mm diameter hole and 6 x 8.5mm counter sunk holes on a 154mm PCD
the standard 51T 520 sprocket is 270mm diameter
plus it would need some larger holes ffor weight reduction while retaining strength and looking finished
ive heard water jet cutting distorts the finished product
any advice on bespoke sprockets would be greatly appreciated
i hope my information is of some help to the community
thanks in advance
Matt (uk)