# what size dc electric motor would i need to make a motorcycle go over 100 mph?

180 pound rider and i dont know how much the bike weighs but it is a suzuki gs550e

seandogue7 years ago
If you don't have any idea of the weight of the bike, then it's awfully difficult to predict how many hp will be needed. It weighs ~450 lbs equipped. How much of the clutter will you be stripping off? And how much will you be putting back on with the Emotor, batteries, and controller? What kind of acceleration do you expect the bike to allow? How long does it need to run? this will affect the AHr rating of your pack and therefore its gross weight (in addition to any other factors affecting the pack size) Aside from the novelty, why a motorcycle, rather than a frame more in tune with the application (modified BMX or road bicycle)? There are a few faux-motorcycle bicycles out there that could be modified to give the impression of a motorcycle without all the weight of the equipment on a real motorcycle made to withstand the secondary effects of being attached to a 30HP internal combustion motor. All rhetorical questions...I'm not terribly interested in answering them but they're what you need to examine at a minimum. Perhaps looking at it from this perspective will show you how to construct the equations that help balance the numbers and determine the HP required for your particular situation.
lemonie7 years ago
Like I said on your previous question, see this one:
https://www.instructables.com/id/How-to-build-a-72Volt-electric-motorcycle/
It claims 70 mph with a 72V motor, which if you look it up is more than 15 HP (follow link to motors website). I don't think you'd need as much as 80 HP, but no less than 40.

L
psymansays7 years ago
Wow, that's asking a lot. Basically, I think you would need at least 80 horsepower (60 kW) to hit 100mph on a motorcycle. You also need the highest voltage you can get, probably 72 or 96 volts. At 96 volts, you need a speed controller that can throughput 625 amps of current. That's a crazy amount, so, you'd probably need about 10 65-amp solid-state relays, in parallel, just to go forward-only. So, that's 8 high-capacity car batteries, a PWM generator with 10 solid-state relays, and a motor designed to power a full-size car, with a very strong transmission. That's gonna make a very heavy bike.