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Discussion Starter #1
So I'm new to this conversion topic.

My project is turning a 1980's Honda CM400T into an electric motorcycle while still using the existing transmission. My concept is to take an electric motor and match the specs of the ICE. Hook the electric motor to the crank shaft where the transmission feeds off of. I've done testing with a simple razor electric motor and control on a 12V system to see if it could at least rotate the rear wheel. That was a success.

I bought a bigger motor with specs of 2000W, 4300 Peak RPM, 48V system and matching controller (It was cheap on amazon and it's to further the idea of fabricating the motor pars to see if it would work). With this idea, I was going to gear the electric motor sprocket to the crank shaft to match the 8500 MAX RPM the original ICE reaches (Roughly 3:1 gearing between the electric motor and the crank shaft).

I'm currently in the process of modifying the case of the ICE to accept the modifications. Meanwhile, I'm going through the original wiring harness and would like to use it as the new wiring harness, but not sure how to hook the two ideas together. Does anyone have a thought on this? What's a basic wiring diagram this type of application where I want to run the lights, turn signals, brake lights, etc. off the 48V system while mainly using the original wiring diagram.
 

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Discussion Starter #3
A 48V 1,800W motor will not be powerful enough to propel a full size motorcycle
…& using the trans usually just wastes energy

I'm runnung a 48V 8,000W motor on my ElMoto @ 5.4:1 (1980 Kawasaki 440 LTD)

Check it out.
https://www.diyelectriccar.com/forums/showthread.php/el-moto-electric-motorcycle-187481.html
I appreciate your comment and I will definitely look over your build as a guide for some of my concerns.

This is some food for thought though...

In a normal ICE, the force from the pistons are relative to the amount of fuel/air mixture and compression with spark (In general terms without going into great detail). The more fuel and air you bring in, the more combustion and force output is being exerted, right? But in that same ICE, there's a limit to what that can reach, max rpm's is a good indicator for that. I believe whom ever did create the transmission thought this same concept as they wanted to get more out of the limiting force from the piston combustion. For a car or motorcycle in this case, each gear in the transmissions allows for further speeds and ranges with the same constant 1500-8500 RPM range the motor gives you.

How come that same concept can't be used with an electric motor? Using an electric motor to run through gearing and prolong the speed and range of the energy being given. Obviously other factors of friction, drag, etc. have be taken into consideration. But if you look at a gearing graph as I have attached, how come an electric motor reach it's max RPM's and use the gearing to increase the speed and range of the motor?

I'm not bashing on you at all, just haven't sen a lot of conversions using the existing transmission and based on what I explained, it makes sense to use one even if there is energy loss through heat and such.
 

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ICE torque curves have very little at low revs and need gearboxes to keep the revs within the hump of the torque curve.

Electric motors have ample torque from zero and often sustain 90+% of max torque up to 50-70< of max revs.
 

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Discussion Starter #5
ICE torque curves have very little at low revs and need gearboxes to keep the revs within the hump of the torque curve.

Electric motors have ample torque from zero and often sustain 90+% of max torque up to 50-70< of max revs.
I figured that was the case, but doesn't that help this idea a bit more though? This would help a smaller electric motor get to high speeds with lower power requirements with the help of momentum and ease of transition into the next gear, would it not? I'm not trying to come off rude at all, just generally interested in this topic. I've heard talk about 3 speed transmissions coming to the newer electric vehicles. Even so, a lower spinning electric motor would help its longevity if you look at it with that aspect?
 

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This would help a smaller electric motor get to high speeds with lower power requirements with the help of momentum and ease of transition into the next gear, would it not?
Not quite. With multiple gear ratios, a greater reduction ratio can be used at low road speed (providing more torque to the wheels), then less reduction ratio at high road speed (keeping the motor within it's allowed top speed, and the speed that it can reach with the available battery voltage). Regardless of the gear ratio or motor speed, the same power is required to accelerate the vehicle at a given rate.

I've heard talk about 3 speed transmissions coming to the newer electric vehicles.
A 3-speed transmission is mechanically awkward, and I haven't heard of any electric vehicle with one, but there could be one.

So far, EVs have almost all been single-speed, because that's all they need: the motor which is large enough to provide adequate power at high speed provides enough torque for low speed without resorting to a lower gear ratio.

There have been some EV's with two-speed transmissions:
  • The original Tesla Roadster had a two-speed, but it was unreliable and Tesla gave up and went to a single-speed... but Tesla Motors at the time knew nothing about automotive technology, so it's not surprising they couldn't make it work.
  • The very limited production Rimac Concept One had a motor driving each wheel, and the rear motors (only) had two-speed transmissions.
  • The coming Porsche Taycan has a similar configuration to the Rimac, with two-speed transmissions in the rear only.
  • The Brammo/Victory Empulse electric motorcycle had a six-speed motorcycle transmission.
The Rimac and Porsche both use a two-speed to get high performance over a very broad range of speed - if they were limited to normal highway speeds, they wouldn't need the extra ratio.

Even so, a lower spinning electric motor would help its longevity if you look at it with that aspect?
An AC motor is so simple mechanically that spinning it more slowly makes little difference - it would only save bearings, which should outlast the vehicle anyway. Avoiding excessive speed would be more important to a brushed DC motor. With any motor efficiency is more important than wear, and there is some efficiency benefit to avoiding both very low speeds and very high speeds.
 

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I appreciate your comment and I will definitely look over your build as a guide for some of my concerns.

This is some food for thought though...

In a normal ICE, the force from the pistons are relative to the amount of fuel/air mixture and compression with spark (In general terms without going into great detail). The more fuel and air you bring in, the more combustion and force output is being exerted, right? But in that same ICE, there's a limit to what that can reach, max rpm's is a good indicator for that. I believe whom ever did create the transmission thought this same concept as they wanted to get more out of the limiting force from the piston combustion. For a car or motorcycle in this case, each gear in the transmissions allows for further speeds and ranges with the same constant 1500-8500 RPM range the motor gives you.

How come that same concept can't be used with an electric motor? Using an electric motor to run through gearing and prolong the speed and range of the energy being given. Obviously other factors of friction, drag, etc. have be taken into consideration. But if you look at a gearing graph as I have attached, how come an electric motor reach it's max RPM's and use the gearing to increase the speed and range of the motor?

I'm not bashing on you at all, just haven't sen a lot of conversions using the existing transmission and based on what I explained, it makes sense to use one even if there is energy loss through heat and such.
Internal Combustion Engines & Electric Motors are very different animals
…& as such, have very different characteristics.

My ElMoto can/will pull up a steep incline (like a big bridge) better than the Turbo Diesel in my truck (& it's very powerful)

https://www.youtube.com/watch?v=5CpeS5ENA18

Also, keep in mind that the cooling fan, in an electric motor, is not very effective unless it spins at an adequate speed
…&/or won't keep the motors internals properly "kooled"

For more info (if your interested) here is a go kart with a 48V 1,800W brushless motor

https://www.diyelectriccar.com/forums/showthread.php/damien-200069.html
 

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Discussion Starter #8
Not quite. With multiple gear ratios, a greater reduction ratio can be used at low road speed (providing more torque to the wheels), then less reduction ratio at high road speed (keeping the motor within it's allowed top speed, and the speed that it can reach with the available battery voltage). Regardless of the gear ratio or motor speed, the same power is required to accelerate the vehicle at a given rate.


A 3-speed transmission is mechanically awkward, and I haven't heard of any electric vehicle with one, but there could be one.

So far, EVs have almost all been single-speed, because that's all they need: the motor which is large enough to provide adequate power at high speed provides enough torque for low speed without resorting to a lower gear ratio.

There have been some EV's with two-speed transmissions:
  • The original Tesla Roadster had a two-speed, but it was unreliable and Tesla gave up and went to a single-speed... but Tesla Motors at the time knew nothing about automotive technology, so it's not surprising they couldn't make it work.
  • The very limited production Rimac Concept One had a motor driving each wheel, and the rear motors (only) had two-speed transmissions.
  • The coming Porsche Taycan has a similar configuration to the Rimac, with two-speed transmissions in the rear only.
  • The Brammo/Victory Empulse electric motorcycle had a six-speed motorcycle transmission.
The Rimac and Porsche both use a two-speed to get high performance over a very broad range of speed - if they were limited to normal highway speeds, they wouldn't need the extra ratio.


An AC motor is so simple mechanically that spinning it more slowly makes little difference - it would only save bearings, which should outlast the vehicle anyway. Avoiding excessive speed would be more important to a brushed DC motor. With any motor efficiency is more important than wear, and there is some efficiency benefit to avoiding both very low speeds and very high speeds.
Great bit of information! I do enjoy learning what others have done. My question to you is, why did that Brammo/Victory Empulse motorcycle have the transmission if it seems to be a waste for the electric motor? I noticed the motor that is in that particular bike is roughly 40kw peak and 25kw continuous with having a max rpm of roughly 5400 RPM.

I also do understand and electric motor is different from an ICE hence why I'm traveling this route. I would like to put this to an ultimate test though.

I just acquired a motorcycle frame (2 actually both with motors, seats, tires, the bare essentials really) for $50 and would like to convert the electric transmission bike and configure it to match the original ICE RPM's as stated before, but then would like to swap that same electric motor I used for the transmission bike and put it to a direct drive, single speed as everyone else has done and truly compare. Basically swap all of the components, controller, batteries, and motor while creating 2 wiring harnesses (Which I still do need help with the schematics as per my original question on this thread was) and see what range, speeds and challenges I come across.
 

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My question to you is, why did that Brammo/Victory Empulse motorcycle have the transmission if it seems to be a waste for the electric motor?
While one ratio is typically adequate, more than one ratio does provide better performance, and most bikes are all about performance. Six ratios (instead of just two or four) does seem pointless; I assume they were just using an available bike transmission. In the case of the Empulse, I think the transmission choice was as much about the riding experience and actual performance - sport bike riders want to be engaged in the experience, and shifting is part of that.
 

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Great bit of information! I do enjoy learning what others have done. My question to you is, why did that Brammo/Victory Empulse motorcycle have the transmission if it seems to be a waste for the electric motor? I noticed the motor that is in that particular bike is roughly 40kw peak and 25kw continuous with having a max rpm of roughly 5400 RPM.

I also do understand and electric motor is different from an ICE hence why I'm traveling this route. I would like to put this to an ultimate test though.

I just acquired a motorcycle frame (2 actually both with motors, seats, tires, the bare essentials really) for $50 and would like to convert the electric transmission bike and configure it to match the original ICE RPM's as stated before, but then would like to swap that same electric motor I used for the transmission bike and put it to a direct drive, single speed as everyone else has done and truly compare. Basically swap all of the components, controller, batteries, and motor while creating 2 wiring harnesses (Which I still do need help with the schematics as per my original question on this thread was) and see what range, speeds and challenges I come across.


Look around, there are many, many electric conversions that have/use the stock trans.
...but, from what I understand, most still don't find it necessary or even helpful to shift/change gears
…& if using multiple gears were helpful, it would be even more helpful in a heavier vehicle, like a car (packed with batteries)

Here is a wiring diagram I drew up of my ElMoto

It's not super detailed but, I'd like to point out how the 48V electrical system is activated by the "stock" key switch (via a relay, connected to where the "stock" ignition coil was connected)
...which means that the 48V system can also be (easily/safely) switched off by the "stock" Off-Run-Off switch (next to the throttle) on the right handle bar, too.


Hope it helps
 

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Discussion Starter #11
Look around, there are many, many electric conversions that have/use the stock trans.
...but, from what I understand, most still don't find it necessary or even helpful to shift/change gears
…& if using multiple gears were helpful, it would be even more helpful in a heavier vehicle, like a car (packed with batteries)

Here is a wiring diagram I drew up of my ElMoto

It's not super detailed but, I'd like to point out how the 48V electrical system is activated by the "stock" key switch (via a relay, connected to where the "stock" ignition coil was connected)
...which means that the 48V system can also be (easily/safely) switched off by the "stock" Off-Run-Off switch (next to the throttle) on the right handle bar, too.


Hope it helps

I personally would still be interested and have more numeric testing to see what differences can actually be made with a transmission versus direct drive.

I greatly appreciate the help with the diagram and will look more into your videos as I start to ramp up on this build after my current project. If I have other questions or more details concerns, I'll definitely get after you and get your thoughts.
 

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So I'm new to this conversion topic.

My project is turning a 1980's Honda CM400T into an electric motorcycle while still using the existing transmission. My concept is to take an electric motor and match the specs of the ICE. Hook the electric motor to the crank shaft where the transmission feeds off of. I've done testing with a simple razor electric motor and control on a 12V system to see if it could at least rotate the rear wheel. That was a success.

I bought a bigger motor with specs of 2000W, 4300 Peak RPM, 48V system and matching controller (It was cheap on amazon and it's to further the idea of fabricating the motor pars to see if it would work). With this idea, I was going to gear the electric motor sprocket to the crank shaft to match the 8500 MAX RPM the original ICE reaches (Roughly 3:1 gearing between the electric motor and the crank shaft).

I'm currently in the process of modifying the case of the ICE to accept the modifications. Meanwhile, I'm going through the original wiring harness and would like to use it as the new wiring harness, but not sure how to hook the two ideas together. Does anyone have a thought on this? What's a basic wiring diagram this type of application where I want to run the lights, turn signals, brake lights, etc. off the 48V system while mainly using the original wiring diagram.
While your researching & planning, here's more "food for thought"
...to "take an electric motor and match the specs of the ICE." you would need a lot bigger motor
(a 2,000W motor is only ~2HP)
...& the first 1,000 or so RPM's are wasted/useless, for accelerating in an ICE
...where as, the RPM's are utilized right from the beginning, in an electric set up

1980 Honda CM 400 T
Engine and transmission
Engine type:Twin, four-stroke 395.00 ccm (24.10 cubic inches)
Power:43.00 HP (31.4 kW)) @ 9500 RPM
Top speed:156.0 km/h (96.9 mph)

* With just a "flick of the wrist" my bike (which has about the same factory specs as yours) can go from 0 to top speed in (~4) seconds

1980 Kawasaki 440LTD
48V 8,000W (brushed) @5.4:1
48V (45V nominal) 2kWh lithium battery pack
Top Speed: ~35MPH
Range: 25 miles

** also, keep in mind that space on a motorcycle is very limited
...how much space will your trans occupy?
...would/could this space be better used for batteries?
 
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