I ended up overvolting my mx650 with 48 volts. I love it but it still struggles with some hills. I don’t need a high top speed so I installed a 89T rear sprocket. I’d like to get even a little more low end by going with an 8T or 9T front sprocket but I can’t find one that will fit with the dual flat hole. Will the single flat fit? Do you have something close that I can modify?
D-bore sprockets with a single flat will not fit the double D-bore shafts.
We recently added a 9 tooth sprocket with 10mm dual D-bore that fits the Razor MX500, MX650, and SX500 dirt bike motors.
It is our item # SPR-2509C and it is available on our #25 Motor Sprockets Page.
A 9 tooth sprocket for #25 chain has a maximum recommended RPM of 2860 though and this is approaching the speed of the MX650 motor so this 9 tooth sprocket should be used experimentally to see if it works well with the bike or not.
A smaller motor sprocket will not cause motor overheating. The smaller the motor sprocket is the lower the gear ratio will be and the cooler the motor will run.
The risk of overheating the motor is when larger motor sprockets are installed and the gear ratio is raised higher because that puts more load on the motor.