Electric Motorcycle – KZ440


Hi Folks!

If you are interested in building your own electric motorcycle, you have come to the right place! I’m working on posting all the information on how I built my own electric motorcycle to share with your. If you are ready to jump right in to building your own, please check out my BUILD YOUR OWN ELECTRIC MOTORCYCLE instructional DVD set!

Here’s a teaser video to get you going.

My electric motorcycle conversion DVD is now available IN FULL, for FREE on YouTube. Watch the PLAYLIST HERE.

For “Chapters” of how I built the cycle, please see the links on the sidebar, or click the links below. I’m currently going through and adding in all the details to this project. Don’t worry if all the detailed info isn’t there yet, I’m going to keep adding to it!

Donor Bike and De-ICE-ing LINK

Electric Motor LINK

Motor Mounting Plate LINK

Batteries LINK

Battery Rack LINK

Charging LINK

Motor Controller and Throttle LINK

Balance of System LINK

Driveline and Gearing LINK

Parts supplies and other links

The cycle uses a single-speed gear reduction. 14 tooth on the drive sprocket, and 72 tooth on the rear wheel sprocket. This low gearing was designed to give the bike good acceleration, with a top speed of 45 mph, the top speed limit in the area that I use the cycle in. (I mostly use it in the city, where it’s all 25 mph zones.)

The Briggs & Stratton Etek motor is rated at 150 amps continuous, and rates as a 8 – 12 HP motor, depending on voltage. With my 300 amp controller, and 48V of batteries, that comes to about 20 HP peak, which you get INSTANTLY from an electric motor. If I swapped out the inexpensive drive sprocket ($10 at the Farm & Fleet store) I could probably go 60 or 65 mph and still be within the amperage rating of the motor, although I wouldn’t have as good acceleration.

The cycle goes 20-30 miles per charge, depending on speed, weather, hills, etc. on 4 Optima Yellow-Top batteries. It charges overnight with a built-in 48V charger. I’ve also charged it directly from a 48V 400 watt solar panel.

Here’s a video of my friend testing the cycle in the parking lot after updating some work on it.

Next, Donor Bike and De-ICE-ing —>

{ 1 trackback }

Mother Earth Fair in Review
June 6, 2012 at 11:05 am

{ 49 comments… read them below or add one }

1 Michael January 9, 2011 at 11:20 am

nice job and congrats on your win for the car keep up the great work.
you are very inspiring.
by the way besides playing with your toys what kind of work do you do are you some kind of engineer or something

2 Alex Kahl @probefahrer January 9, 2011 at 11:36 am

coooool! where can we more of that bike?

3 Ben N January 9, 2011 at 12:26 pm

I am not an engineer.
I have a library card, internet access, and talk to whoever I can learn from.
I am self-employed and do some work in video production and odd jobs. I simply learn all I can while working on anything. Really, if I can do this kind of stuff, anyone can!

4 Ben N January 9, 2011 at 12:29 pm

See more videos on the motorcycle at MY YOUTUBE EV MOTORCYCLE PLAYLIST.


5 sonny June 16, 2011 at 1:53 pm

Awesome stuff Ben! Just wondering what the specifications of the bike is? Like 0 to 60, range on one charge, how long does it take to charge?

6 Ben N June 20, 2011 at 10:26 am

Sonny, there’s no 0-60 time on it, because it was designed for use in the city. The single-speed gearing is set up for 0-45mph, but with no clutch, and no shifting.
It goes 20-30 miles per charge, using four off-the-shelf batteries, and recharges in 8 hours or less.

7 Patrick August 3, 2011 at 4:15 pm

Hey Ben, I have always been interested in buliding my own electric motorcycle. But I want to build a bike that has a decent range like 60-70 miles. I dont know what that would take but I think it would be a great goal. There are electric motorcycles on the market with that type of range and some even have 100 mile ranges or more. I know the batteries they use are high tech, but there has got to be a way I can do it with sealed batteries. So how do I do this? Also what would be a good starter bike? I guess I need something lightweight so I can go farther.

Thanks alot!

8 Patrick August 3, 2011 at 4:21 pm

Oh yeah by the way your presentation was awsome, it was the most detailed one I could find on the internet. I was just hoping someone would ask a question about range. I am a college student so if I built an electric motorcycle it wouldnt just be a toy or luxury, it would be my daily driver, so it would be nice to have a bike with better range so it can go everywhere a gas powered motorcycle can.

9 admin August 4, 2011 at 9:09 am

A lightweight motorcycle will help with range. Still trying to cram in up to 100 miles range is asking a LOT!
I did recently test ride a Zero S. It was great! Very light, belt driven, and SMOOOOOOTH!

I also saw a fantastic homebuilt cycle at the Detroit MakerFaire – see that guy’s web page at: http://experimentalev.wordpress.com/
Sport bike frames can make excellent conversions because they have a lightweight frame and when you remove the engine and transmission, it leaves a nice space for you to build a rectangular area to hold even more batteries!

10 justin April 2, 2012 at 6:44 pm

i was wondering, im tryin to make my electric vehicle, and i kinda need info on which would work better for my vehicle.. a belt of a chain because my vehicle is of my own design and everything and i want to make it as powerful and eassy on the battery as possible so that i can be my main car..

11 admin April 2, 2012 at 7:06 pm

My cycle uses a chain, because it’s simple, and easy to change gear ratios on. Also, I’ve heard that a chain can be more efficient, because it can’t slip. I got to ride a commercially-built electric motorcycle a while back that had a belt drive. It was very nice and quiet. I think a cogged belt would be a great way to go, but I imagine it would be a bit more expensive for the parts than stock chains and sprockets would be.

12 justin April 2, 2012 at 7:47 pm

whats a safe amount of batteries you can use without turning yourself into a crispy critter??lol because i was thinking of using about 6 l-ion batteries for my power source..

13 admin April 3, 2012 at 9:17 am

By “amount of batteries you can use”, I’m assuming you are asking about system voltage. On a DC system, higher voltage makes your motor spin faster. Higher voltage at the same power is lower amperage, which is good for range, and higher voltage at the same amperage is higher power, so there are all sorts of good reasons to go with higher voltages. “Low-Voltage” is usually considered anything around 42 volts or lower. That’s the point at which, most likely, the voltage won’t penetrate the skin and give you a shock. But that also assumes that you are touching bare wires or battery terminals. U.S. household wiring is 120V and we really never think anything because of it. But all the wiring is covered, and we have safety systems – grounding and fuse boxes. It’s the same with an EV. There really isn’t a particular voltage that you are going to “fry yourself” at. Higher voltages do have a higher risk of electric shock, assuming that you did NOT properly build your system with shrink tubing, battery boots, and work on it with the power connected.

Lead acid batteries are typically 12V, but Lithium are usually somewhere in the 3V range. You build several cells together to make a “12V Battery”. A 72V lithium motorcycle would be great, but remember that you will need something like 24 lithium cells, not 6 batteries.

14 sweed April 3, 2012 at 9:46 am

hello, im wondering if that engine is strong enough if you want to make it go faster???(You’ll have to excuse the english)

15 admin April 3, 2012 at 10:02 am

The electric motor that I’m using is rated to pull 150 amps continuous at 48 volts. When I am cruising on the cycle, it uses a little less than 100 amps. By changing the gearing, I could increase the top speed, but also pull more amps. Since I live just outside a city, where the speeds are low, I’d rather have the lower amp draw and top speed, but YES, the motor is powerful enough for a higher speed.

16 justin April 3, 2012 at 1:15 pm

thanks ben big help, ^_^ i watched your vids on youtube in high school and decided to try to make my own and this will be my first (hopefully best and last) vehicle so i want to say ty for the inspiration dude! ๐Ÿ™‚

17 admin April 3, 2012 at 1:28 pm

You are welcome! Just make sure to send some photos and videos this way when you are done with YOUR project to inspire others!


18 justin April 3, 2012 at 1:47 pm

will do !!

19 justin April 4, 2012 at 3:03 pm

hi ben
justin again, does your video one the electric car show you how to hook up the aircon and radio to your powersource? cuz i only have your motercycle video, and it doesnt quite cover that part of my inquiry to give you an incite on what im trying to do.. im mixing the motercycle tech with the car comforts and tech into one awsome vehicle so if yes i’ll go ahead and make the purchase to get it of no, i’ll just have to figure a way out lol ^_^

20 sweed April 4, 2012 at 4:33 pm

Thanks for the answer!;-)
I aint very good at this electrical stuf so i’ll ask you, do you think one can build somthing like that with a washingmachine motor couse im looking for the cheepest solution i can find for the summer when they are raising the gasoline prizes here in sweden all the time…

21 admin April 4, 2012 at 5:34 pm

BUILD YOUR OWN ELECTRIC CAR does NOT cover air-conditioning, just because my particular car didn’t have it. Power for things like the radio, headlights, airbags, etc. are all untouched. Those all run off the existing 12V electrical system, which is un-modified. The only change to that is adding a 12V charger or a DC/DC converter to the original 12V car battery.

For most electric vehicles, you have TWO electric systems, one at 12V for the original vehicle radio, lights, accessories, etc. and it ONLY does that, and a completely separate HIGHER voltage system that’s just for propelling the vehicle. There’s all sorts of good reasons not to mix the two, including that nearly all cars use the frame of the vehicle as the 12V- of the electrical system!

22 admin April 4, 2012 at 5:42 pm

Most washing machine motors are not nearly as powerful as you would need to drive an electric vehicle. HOWEVER, there are now starting to be clothes washers that use a direct-drive AC motor. It’s a powerful motor right on the drum of the machine (instead of off to the side, and driven with a belt) which produces enough torque to spin a whole tub of wet clothing. If you had several of these motors, you might be able to build “hub motors” from them, where the motor drives a wheel directly. You would still need to figure out how to drive the AC power to the motor(s) and control their speed. Paul, at the Open Revolt project has been working on an Open Source AC Motor Controller. Perhaps several direct-drive AC clothes washer motors and an Open Revolt AC controller might make for a good start on a purpose-built vehicle.

I haven’t heard of anyone doing this yet, but it is certainly within the realm of possibility!

23 justin April 4, 2012 at 8:23 pm

ok ty for the info ben , do you know any sites i could go to to study the electronic systems of a basic car?? cuz im stumped at the moment for that part lol any wisdom from ya i would be grateful for sir ๐Ÿ™‚


24 sweed April 5, 2012 at 9:06 am

so you don’t think it would work even if its low geared? or that it would be hard to get it to work…

25 admin April 5, 2012 at 9:30 am

I think a web search for “Car 12V electrical” will get you all sorts of web pages that will help you out.

26 admin April 5, 2012 at 9:55 am

There are a lot of different types of motors out there, including motors from washing machines and other salvaged machinery. The important thing to keep in mind is how much power you can put through them, and how much is needed for your project. For my motorcycle, the motor is rated for 12HP at 48V. How many horsepower can an unknown motor from a washing machine put out? If you can find out, and it’s in the range that might work, great, go for it! You CAN using gearing to increase torque, but at the expense of speed. Depending on the motor and how you want to use the vehicle, that can be fine too. My cycle is geared in such a way that the top speed is 45 mph, but I’m just outside a city where it’s all 25 mph zones anyways, and only 45 just before my house.

27 sweed April 6, 2012 at 6:53 pm

hello me again, you must think im a pain in the…
but im just curius;)
how much power do you think one can put out from a car alternator if you convert it into an electric motor?
(not for a motorcycle, only for fun)

28 Ben April 7, 2012 at 10:30 am

I believe that most alternators are designed for about 65 amps, while outputting 14.4V. If you multiply 65×14.4, you get 936 watts. Lets just call it 1000 watts for easy math.

Assuming you could easily convert an alternator into a motor, you should not expect to be able to convert any more than 1000 watts from electric power to mechanical power. That’s about 1 and a quarter horsepower. It might be good for something like a kick-scooter.

Power is pretty easy to figure out in general watts = volts times amps. Horsepower is roughly 750 watts. There’s lot of different types of motors out there, of different sizes, power, and cost. Very small motors generally are NOT appropriate for any kind of vehicle use, but taking something apart, and learning how it works can be lots of fun!

29 sweed April 7, 2012 at 1:08 pm

Thanks, that was about what i belived!
But would it work for “instant” use?

30 admin April 7, 2012 at 6:35 pm

Hey, anything will work once, at least until you melt it!

31 Brian Curtin May 24, 2012 at 10:39 pm

Greetings! Have you considered building your KZ440 (or variants) for sale to the public? I have no tech skills whatsoever and I would be interested in purchasing one with more range and speed. Thank you for your reply.

32 Brian Curtin May 24, 2012 at 10:44 pm

Second question: Why can’t a generator be connected to the drivetrain in some way to recharge the battery so that it would be a self perpetuating apparatus?

33 Ben May 25, 2012 at 10:38 am

My entire project cost right around $2000, starting with a used frame in poor condition. I put a lot of hours of work into the project, which is great when it’s being done as a hobby. If I had to charge for all my labor, it would end up being rather expensive. There are commercially available electric motorcycles from brands like Brammo and Zero that a person can already buy. I’m encouraging people to build their own electric motorcycle, to save money, learn about electric vehicle design, and take pride knowing that they built it themselves! As such, I offer for sale an instructional DVD teaching people how I built mine, and how they can build their own.

34 sweed May 31, 2012 at 9:42 am

hello there, iยดve just found a electric lawn mower engine(BOSCH) and it was pretty strong and fast when i tryed running it whit only one 12v car battery. i was thinking of putting it on a bicycle with two car batterys wired in series and having it belt driven… what do you think about that??, would two be enough???

35 admin May 31, 2012 at 11:23 am

Sounds like fun! Try it out!

36 Samuel June 5, 2012 at 9:19 pm

First of all, Ben’s motorcycle build has been a great resource for my build plans. I do, however, have a few questions. The first invovles the range estimates: voltage x amp hours / 100 = the range. I used this to estimate the range I will have, but it seems unreal, it’s over 300 miles. Am I doing it right? I am using 22 batteries, each one being 3.2v and 20ah for a total of 72v and 440ah. The next question concerns gearing. How many teeth are the front and rear sprockets? My stock sprockets are 16t front and 42t rear. With a rear tire diameter of 25.8 inches and a top motor speed of 3240 rpm (45 rpm per volt) I am estimating 96mph top speed. It is a little faster than Ben’s 45 mph. Can this be right, and with that gearing will it be able to move from a standing stop? Thanks for any opinions.

37 Samuel June 5, 2012 at 10:47 pm

One last question. As mentioned, I will be running 22 3.2v 20ah batteries which will be wired in series to get 72v. In order to run 12v lights, I am planning to wire another circuit grouping all of the batteries in paralell to get my 12v (well some series to get from 3.2v to 12v). Will this work or will I create some sort of nuclear melt down or something? Thanks

38 Ben N June 6, 2012 at 7:33 am

Your math is a little off. When you add up batteries (cells) in series, you add the VOLTAGE, but the amperage (and AH) stay the same. When you add batteries in parallel, the voltage stays the same, but the current or capacity (Amps or amp-hours add up). You can add one or the other, but not both!
22 cells times 3.2v = 70.4V, at whatever your original capacity is, 20AH. 70.4v x 20ah = 1408.0 watt-hours. Divide by 100 watt-hours-per-mile gets you 14.08 miles per charge. My pack is 48V at 55 – that’s a 26 mile range.

My gearing is 72 tooth rear to 14 tooth front for a little over a 5:1 ratio. This is probably a little lower gearing than I need. I have great power pulling away from stops. The gearing limits my top speed to 45 MPH, but that’s the speed limit right in front of my house anyways. With my motor and gearing, it just happens to work out to about 1 mile per hour per battery volt. If I was at 72V, it would do freeway speeds. With gearing of 42:16 or 2.625 you would be pulling twice as many amps at all times as my gearing would. You could start out using your existing gearing and see how it works for you. Use an ammeter to measure how much amperage you are pulling at takeoff and cruising, and see if it is reasonable or not. In general, electric motors are happier spinning faster and getting geared down. They generate less waste heat, and the internal cooling fan spins faster as well.
When you aren’t happy with the gearing, go to a larger sprocket on the rear wheel for a lower gear (you make the rear sprocket bigger because you can only make the front one so small) There are many places you can order larger and custom sprockets from. I ordered one from a place called Sprocket Specialists, and have been very happy with it.

39 Ben N June 6, 2012 at 7:43 am

It’s rather tough to group batteries in series to do one thing and also in parallel to do another. It’s really asking for trouble as you are that much more likely to cause a short circuit somewhere.
A much better way to go to use a “DC to DC Converter”.
The DC/DC converter takes one voltage of DC and converts it to another voltage of DC. So, you can take your full 72V pack, run it through the converter, and get 12V out the other end. You then run that 12V to your regular fuse box, and from there to your headlight, turn signals, horn, and the rest of your 12V system.
The DC/DC I’m using is a computer component that I bought for $10 on Ebay. Just make sure you get one rated for your system voltage, with the correct output. (Many are adjustable to 13.5V or higher for charging a 12V battery.) You also want one rated at high enough wattage for your needs. Mine is a 100 watt. My headlight is 55 watts, so that’s the main draw, and leaves more than enough overhead for turn signals and the other basics.

40 Samuel June 7, 2012 at 9:42 pm

cool, you saved me there. I was able to cancel the order on the batteries, and I am now looking at a set of 120ah batteries. The only problem is contending with the size and weight. ugh! How did you mount the front sprocket to the motor? Obviously a custom mount, but was it something you did your self or had it made at a machine shop? Also, when you are nearing the limit of your range, can you tell a difference in power, or does it just keep going until it dies? Thanks

41 admin June 8, 2012 at 8:56 am

The sprocket that goes on the motor is easy. The motor had a standard driveshaft (7/8ths of an inch) so I just got a hub that size and a sprocket with 14 teeth designed to go on there, and welded the hub and sprocket together. It’s very simple.
See http://300mpg.org/projects/evcycle/driveline-sprockets-and-gear-ratios/ for more details on the sprockets, chain, and gearing.

For DC motors, the higher the voltage the faster the motor spins. As a battery pack runs down, it’s voltage also drops. So, with no other voltmeter/ammeter/or other instrumentation, you can tell that you pack is running down by your top speed dropping.

42 sweed June 25, 2012 at 10:47 am

god eftermiddag! thats “good afternoon” on swedish.
if one have several batterys wired together, will all of them be charged if I put just one charger on just one battery?

43 admin June 25, 2012 at 3:38 pm


If you put just one charger on just one battery, only that battery will get charged.

You want to either have one charger on EACH battery OR have one single charger that is the voltage for the entire battery pack (48V for example) that charges ALL the batteries.

The main thing is that you want each and every battery fully charged every time.

44 Justin M August 3, 2012 at 4:37 pm

Hello! i have a question. the only motor i am able to find a a Dayton 3/4 HP 115/230 V AC motor. would i need an inverter? and what should i do as far as the motor controller?

im plan to run it on a 48V system


45 Justin M August 3, 2012 at 4:44 pm

Also would it be bad to run batteries with the same V but different AH?

thanks again!

46 admin August 3, 2012 at 5:06 pm

AH is just the capacity of the battery. You can think of this as the size of the “gas tank”. Bigger is better, until you can’t fit it in the motorcycle anymore! The only other thing to keep in mind is that how many amps you can pull (A) from the battery is typically related to the capacity of the battery (AH). For example, don’t expect to be able to pull 500 amps from a 20AH battery!

47 admin August 3, 2012 at 5:09 pm

AC motors are totally different beasts than DC motors. You would need an inverter, and if you want to do anything other than one set speed, you would need a variable frequency drive (VFD) And only 3/4HP? My cycle is is 12 HP.
Keep looking around, a 3/4HP AC motor is NOT the right thing for an electric motorcycle.
Take a look at some of the motorcycles on the EV Album for a better idea of what motors people have been using for their projects.

48 Doug December 30, 2012 at 10:38 am

Hi Ben,

I’m pretty much useless when it’s come to electrical but I was wondering if the batteries they make for large automotive stereo systems might be usuable? (http://www.kinetikpower.com/2009/default.asp) <<<like these) From my understanding they pack more punch than normal car batteries and are quite a bit smaller as well.

49 admin December 30, 2012 at 10:46 am

The Optima YellowTop batteries I used in my electric motorcycle project are marketed to people with “extreme power needs” on their vehicles, such as large car stereo systems. I’ve been very happy with them. For lead-acid batteries, AGMs are best suited for an electric motorcycle.

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