Custom bike sprockets
 

I'm about to assemble the electric motorcycle I have and about to mount the motor. Next step is the sprockets. I'm going with a 5:1 ratio, so I need a 70 tooth rear sprocket. I'm having a hard time finding vendors who offer 70 teeth for a 1996 Honda CBR 600 F3. Does anyone know of any vendors who make 70 tooth sprockets for motorcycles? What prices should I be looking at?

IIRC stock for a CBR F3 is 14/43. I know you can get a 13T front and 46T rear in the aftermarket but I don't think you will get a 70 tooth even going custom.

Your best bet would be to try to find a place that sells stunt bike parts. Typically that niche market isn't concerned about speed but power to do their tricks...Which is promising for what you need.

It's for an electric motorcycle, so nothing is stock anymore. I found one vendor (actually it's my friend's dad's place) that has sprockets up in the 70 tooth range, but they're asking $125 for the anodized aluminum sprockets.

specific tooling investment divided on very small batches of parts = high selling price, that is just fair.

It's either 125$ sprocket (and chain to the meter obviously) or you could engineer a twin reduction setup based on standard sprockets.
Standard front sprockets drive standard rear sprocket that drives standart front sprocket that drives standard rear sprocket.
All in all, you end up with a setup that might be more expensive to start with (but a fair bit less on the long run).

I'd go for the 125$ custom sprocket ...

electricmotorsport.com makes custom sprockets. if I remember correctly they are about $100.

So $125 is the going price for custom sprockets? I didn't know if that was high or not.

Rebel Gears in Crossville TN will make sprockets up to 96t. REBEL GEARS CUSTOM MADE MOTORCYCLE SPROCKETS ANY SIZE

Most custom sprocket places I'm finding ask for measurements and bolt patterns. I don't have the proper measuring tools, except a tape measure. Off hand do any of you know of a database that hosts sprocket measurements and dimensions? Sort of like those websites that sell tires and rims and they have all of the OEM information.

if you know the donor bike, visit The UK, there is a pic of bolting pattern for each sprocket

Also, I would really appreciate a link to the build diary of your EV conversion !