Question on Dual motor Shaft Driven Motorcycle. (Electric Boxer engine)

[seranikas]

I had a thought from seeing how the Boxer engine on some Honda and BMW motorcycles were built. Is it possible or feasible to build an EV converted motorcycle using a similar design. Dual engines on the edge of the frame connected via a shaft or wheel/pulley system to connect with drive shaft. In theory this can leave a lot of extra room for the more battery and necessary components inside the frame as well as balance the bike more efficiently without requiring to move items around to recenter the weight. .

However the question is if having two moderate sized motors will be as efficient as one larger motor in the frame. Most shaft driven builds I see have the motor connected directly to the shaft or one a pulley to add more torque. Similarly what type of motors would be useful for this kind of build. For example the Goldwing has the engine and protective bar come out an extra 10 inches off from the frame on both sides. This could give it enough extra space to mount the motors to the sides.

Two designs I thought of were using the pulley with the motors in parallel with the drive shaft. Similar to how the Goldwing engine is already with their pistons in line and connected with a timing belt at the front. The alternative would be to have two slim motors perpendicular with the original drive shaft connected in the middle with a 90degree gearbox that will then connect with the shaft.

Another alternate design had the potential of adding a 4 speed gearbox inside for some speed/torque control.

Thoughts on this design/concept?

Below is the a diagram of what i feel this concept could look like. Gearbox was an idea of an inline stepdown motor to convert speed to torque. (Not to scale or aligned)

Belt and pulley



Shaft and gearbox.

 

[scianiac]

One larger motor will be more efficient for several reasons but assuming there was no difference one motor would still be better just to save space. One motor with much less belts/chains will be smaller and you want all the space you can to fit batteries. The same goes for gearboxes which in 95% of cases it's better to spend the weight, space, and drag of a gearbox on a bigger motor, controller and more batteries. You have to remember that the space that a motor powerful enough to make the bike fast enough for any reasonable use is actually quite small compared to the space available and the space for batteries needed to power that motor.

 

[seranikas]

One larger motor will be more efficient for several reasons but assuming there was no difference one motor would still be better just to save space. One motor with much less belts/chains will be smaller and you want all the space you can to fit batteries. The same goes for gearboxes which in 95% of cases it's better to spend the weight, space, and drag of a gearbox on a bigger motor, controller and more batteries. You have to remember that the space that a motor powerful enough to make the bike fast enough for any reasonable use is actually quite small compared to the space available and the space for batteries needed to power that motor.

that makes sense. thanks for the reply.