About: Ordinary guy with no special skills, just trying to change the world one backyard invention at a time. See more at: On Twitter – @300MPGBen and at
The finished project is a 1981 Kawasaki KZ440, converted to electric. It is powered by four Optima Yellow Top sealed (AGM) lead-acid batteries, that drive a Briggs & Stratton Etek electric motor. The speed of the motor is controlled by an Alltrax brand AXE programmable controller that can run at up to 48 volts and 300 amps. Contrary to popular belief, and electric motorcycle is NOT silent, but is CONSIDERABLY quieter than a typical gas cycle.
The cycle is GEARED to 45 mph, has fairly good acceleration, no clutch or transmission. Theres no oil to change, to mufflers to rust off, no air filter, no carbs to tweak, and no gasoline. I designed it for primarily city riding. The top speed and acceleration could be easily changed by swapping out a $20 stock sprocket.
The cycle recharges from the wall, through arenewable energy program, and if there is a blackout, I can actually run my house off my electric motorcycle! In the future, I hope to expand my system to include charging the cycle with photovoltaic solar panels. Real-world range per charge is 23-32 miles, and charging takes less than 10 hours for a full charge. ( A different charger could charge them even faster – see details on the Batteries PDF)
In this Instructable, Ill walk you through the work required with the motor, batteries, controller, and mounting all components, including showing you some low-tech paper and cardboard CAD tricks.
But what do you want? You might not even know yet. I always encourage people to take a look at theEV Album. Its an on-line listing of mostly home-converted electric vehicles. Each listing shows the make and model of the vehicle, the cost to convert, the speed and range, and other specifics of each project. You can also search by type of vehicle or brand name.
For example, if you go to youll see a wide variety of electric motorcycles. Different brand names, lithium and lead-acid battery types, and a wide range of costs of conversion. Likewise, if you want to see Scooters, Mopeds, and Minibikes, you can visit
Give some thought to what cycle you would like to convert. Do you like sport bikes? Great! They have a lightweight and strong aluminum frame! Do you like standard? Great! Theres lots of those out there and you can show off the motor and batteries. Hang out at biker events with your unique ride!
If you arent sure what to expect in terms of range per charge and top speed, dont worry, online calculators can help you out.
For more on my electric motorcycle,electric car, and other projects, swing by my blog at
If you are interested in building your own electric motorcycle, but want even more information, more details, and hands-on style instruction, check out theINSTRUCTIONAL VIDEO DVDthat I created to teach how ANYONE canBuild Your Own Electric Motorcycle!
As of January 2018, Ive now posted the Instructional DVD, the entire 2 hours and 40 minutes of it, FOR FREE on YouTube. The DVD is broken down into shorter sections and available as a playlist.
It may be cliche, but every shop class, repair book, and seminar starts off talking about safety.
The reason why is because ITS IMPORTANT! Any type of work always has some sort of risk to it. Minimize that risk, and protect yourself by thinking ahead and using proper safety equipment.
Ill hit a few of the basics here, as well as a few you may not have thought of that are particular to this project.
Wear yoursafety glasses, work gloves, and hearing protection. If you already wear eyeglasses, the larger boxy type safety glasses work well over your eyeglasses. Otherwise, add side protectors to your existing glasses. If you dont wear eye-glasses, I like the the slimmer style that fit tight to the face. This is the same type some motorcycle riders wear out on the road. Heck, get yourself a nice pair, and they are multipurpose!
Wearingwork-gloveswill save your hands a lot of cuts and scrapes. Thick leather gloves are durable, but clumsy. Mechanics gloves give you much more dexterity. I prefer these, as I can leave the gloves on while using any type of tool. If you have to take gloves on and off to use a particular tool, it doesnt take long to give up on wearing gloves. Wear welding gloves when welding. Latex or other rubber gloves are sometimes handy for working with fluids or while painting.
Wearhearing protection. During any drilling, cutting, or grinding, you should be wearing hearing protection. Soft ear plugs are cheap and disposable, and pretty comfortable. I like the big ear-muffs because they are easier to take on and off than soft plugs are to take in and out. I like having normal hearing while I am not cutting and grinding.
Remove jewelry, or at least cover it up. Besides getting caught on a moving part, most jewelry is also extremely electrically conductive. Remove rings, wrist-watches, necklaces, wallet chains, and that big key chain hanging on your belt loop. Dont wear big conductive belt buckles that can also scratch paint-jobs. If you cant or wont remove a piece of jewelry (wedding rings, etc.), cover it up. Wearing work gloves will cover a ring, and a necklace can be tucked inside your shirt.
Clothing.Im sure youve worked on enough projects that you know what appropriate clothing is. Typically, you want long shirt sleeves and long pants. Dont cuff your pants. Metal shavings, dirt, and possibly hot metal likes to get caught in there. Wear closed-toe shoes or boots, preferably leather, and safety toe if you have them. Natural fiber clothing is also preferable. In a bad situation synthetic fibers can melt (onto a person!) At least wear a cotton T-shirt under your fleece sweatshirt….
Now onto a few things that are more specific to this project.
Motocycles are powerful, heavy enough to hurt if they fall on you, have chains and sprockets, and run on electricity by the time we are done with it.
That brings up a few safety cautions of particular concern:
Pinch Points:Be really careful where the chain and sprockets come together! Always make sure you have the chain guard in place. Build a custom chain guard if the project requires it. I once got my finger pinched between the chain and back sprocket when I was adjusting the chain. YEOWCH! That was just with me turning the back wheel slightly by hand. Id hate to imagine if the same thing happened with the motor running!
Electric Spark and Shock:Always keep covers on the battery terminals. Never work on the cycle with the power connected. Always have the real wheel off the ground when testing the vehicle. Keep conductive materials away from the batteries. 48 volts is right on the border of what is generally considered low-voltage or not. Risk of shock is fairly minimal, but all electricity should be taken seriously. SPARK is a greater concern. 48V short circuited has the potential to create large sparks that can melt battery terminals and propel molten lead. Always wear safety glasses when working on batteries and battery connections.
I recommend covering the handles of your battery wrenches with shrink tubing. You get a nice snug grip on your wrench and greatly increase its electrical resistance. You could also use electrical tape, but thats just going to make everything sticky eventually.
Lifting and Jacking:Chances are, you will want your cycle elevated. It makes it much easier to work on, as it prevents you from bending over, and working from floor level. I recommend a motorcycle lift. A small, sturdy table can also make a good stand, but its challenging to get the cycle on and off that stand safely.
Whether using a lift, jack, or stand, make sure the cycle is SECURELY attached to it with straps or some other means. An elevated vehicle could easily become unbalanced while working on it, falling off the stand, damaging the motorcycle or landing on you, your other projects, or someone you love.
Use your multimeter correctly.Many typical multimeters allow for you to test voltage, amperage, and resistance. To test amperage, you have to physically move one of the probes to a different jack on the multimeter. MAKE SURE YOU MOVE IT BACK when you are done with the amperage test. Even if you flip the control on the multimeter back to voltage reading, but forget to put the probe back in the right connection point, the next time you go to test voltage, you will melt the tip of the one probe off in about one billionth of a second. And it scared the bejeezers out of me. I mean you. In theory, if that happened, it would really startle you. So make sure you use your multimeter right.
Dont smoke: Smoking is a fire hazard. Especially when you take the gas tank off.
Dont drink alcoholwhile or before working on the project. It impairs judgement, and you might do something stupid. Likewise, do not drink, smoke, or do other drugs while RIDING. Go for a ride, come back, and THEN have your beer.
Isnt getting insurance the last thing you do before you go on the road?
You do NOT want to go through all the time and expense of building an awesome electric motorcycle, only to find that you can NOT legally ride it!
Some legal reasons you may not be able to legally ride your cycle in your area may be due toRegistration, Insurance, or License.
None of these things are that complicated, but you must comply with whatever the rules are in your area. (If you have a large private property, and will not be using this vehicle on-road, you may be able to ignore this.)
Registering your cycle should be done exactly the same way any typical gasoline powered cycle would be done in your area. In some places, cars are required to pass a smog test, but motorcycles are exempt from that. A vehicle may also be exempt from certain tests or requirements if over a certain age (Classic or Antique) or primarily for show and exhibition or part-time use (Hobbyist.)
It seems that motorcycles are sold much more often WITHOUT a title than cars ever are. Make sure you get a title and bill of sale with the VIN – (Vehicle Identification Number) printed on it. If you do NOT get a title, make sure that you will be able to get one. This can sometimes require additional cost, paperwork, and/or vehicle inspection. Sometimes an inspection may require a matching number on the frame, engine, and transmission. Because of that, I recommend registering your vehicle as it is BEFORE removing the engine or transmission, even if it doesnt run.
A VIN is extremely important. I personally know somebody who built a pretty nice electric motorcycle from scratch. He made EVERYTHING on it, from the frame on up. He couldnt get it registered or insured. Without a VIN, registration may be possible (but lots of jumping through hoops) but extremely difficult. Without a manufacturer Make and Model, he couldnt get insurance. Eventually, he just took the cycle apart and used the parts on other projects.
By CONVERTING an existing motorcycle to electric, we have the VIN, Make, and Model to make the project fit inside the box for the government and insurance.
INSURANCE:One of the first things I did before really getting going on this project was to call my full-service insurance agent. I told her exactly what I wanted to do. Motorcycles are commonly modified and customized. This was really no different. I had no problems getting insurance. My insurance is about $100 a year and provided through Progressive.
Before starting your project, talk to an insurance agent. The year, style, or engine size of the motorcycle frame may dramatically effect your rate. A 1500cc crotch-rocket is likely to cost more than a 250cc standard cycle. Since you are removing the engine anyways, just get a cycle that you like, with enough room in it for the motor and batteries.
License:If you dont already have a motorcycle drivers license, get one. I signed up for a course at my local college. Besides being excellent training for a first-time rider, the class also gave a benefit of streamlining the process (and reduced the cost!) of getting the motorcycle endorsement at the Department of Motor Vehicles. Even if you are a long-time rider, an electric motorcycle will perform slightly different than an engine powered machine. Some colleges and other training centers also offer advanced and specialized rider training.
I have heard of people converting a small to medium sized motorcycle to electric and getting it titled as a moped. In that case, you do not need a motorcycle endorsement, but you cant legally carry a passenger either. You may also be restricted to which roads you can ride on.
Once again, make sure you check AHEAD OF TIME on all the legal requirements in your area for vehicle operation. Its pretty exciting once your electro-cycle is completed, and youll want to be ready to hit the road!
Now that we made it through the basics of safety and legal, you want to start that search for your
. You may already have something thats been sitting around with a bad engine or transmission. Otherwise start looking for your cycle. You may want to check out Craigslist, the local newspaper classifieds, or stop and see every motorcycle for sale on the side of the road.
Besides just overall style and finding something that fits your budget, heres what to look for in the donor bike.
It might sound obvious, but get something thats in fairly good condition. You want to do a conversion, not a restoration! Make sure the turn signals and headlight work. The horn should work. It shouldnt be all rusted out. Get something that looks nice enough and will be fun to ride. If you happen to be somebody who regularly builds custom motorcycles and restorations, just ignore what I said. Go hog-wild instead. I do have to admit that the cycle I bought to convert to electric was not in very good shape. The price was right though. In the end, fixing all the little things on it took a fair amount of time and work. Looking back on it now, I would have preferred to spend a little more money and and have had fewer things to fix.
SAVE MONEY WITH ABADENGINE OR TRANSMISSION
In this conversion, the original engine and transmission are NOT used. If you buy a motorcycle that is in pretty good condition OTHER than a bad engine or transmission, you might be able to get a really good deal on it. Just make sure to keep the engine and transmission with for a while to confirm proper registration.
SAVE MONEY WITH AGOODENGINE AND TRANSMISSION
If you choose to buy a cycle in good running condition, make sure to carefully remove the engine and transmission. Keep all the parts together, label everything, and keep it out of the weather. Sell the engine and tranny to make some money back on the purchase of the cycle.
Most motorcycles are driven by a chain, but some use a belt or even a driveshaft. Get a donor bike with a chain. This will give you the most flexibilty and efficiency. Chains are cheap, dont slip, and are easy to change gear ratios by swapping out an inexpensive sprocket. Electric motorcycles CAN be built with a belt or driveshaft, but it is more of an advanced project and has other considerations.
You will want a cycle with enough room in its guts for the motor and batteries. A too-small cycle will limit where you can put the motor and batteries, and how many batteries will fit. An extremely large cycle gives you plenty of room, but the frame may become heavy quickly. Popular choices include sport bikes and medium-size standard cycles.
Sport bikes typically have an aluminum frame (light-weight) and it is shaped with two supports over the engine, and two under it. This gives you a box to mount your batteries. Sport bikes also usually have some sort of plastic fairing over the engine. After conversion to electric, you can put the fairing back on, and look almost stock.
A medium-size standard will have two frame supports under the engine, which can be re-used as a base or tray for mounting the batteries. You will most likely want to avoid any cycle that has a single piece of frame above or below the engine. It just makes it more difficult to find a way to mount the batteries. You can always fabricate something custom, but its best to start with a solid foundation.
Most cycles have a mechanics repair manual available for them. You might be familiar with the Haynes or Chiltons brands for car repair. Find the book for your cycle. Although it wont cover the new custom electric system, it will tell you how to fix your brakes, align the chain, painting tips, general repair and maintenance, and have plenty of other useful information.
Once you have your donor bike, you need to De-ICE it. ICE stands for Internal Combustion Engine. Youll be removing the engine, the transmission, and anything else related to that system. That includes the gas tank, the exhaust pipes, and a radiator if it has one. Remove these parts carefully, so you can re-sell them.
You will want to know where to put the electric motor for the conversion. The easiest way to do that is simply to put the electric motor exactly where the output shaft of the transmission was. Locate where the chain goes to on the transmission end and mark that location on the frame. Use a wax pencil or silver marker with a speed square to put a mark on the frame both vertically and horizontally from the output shaft of the transmission. You will later use these marks to position the electric motor.
Add TipAsk QuestionCommentDownloadStep 4: Electric Motor
To power your motorcycle, youre going to need a motor. But what type, what size, and where do you get it from!?
This project used a Briggs & Stratton Etek. Its a DC (Direct Current), brushed, pancake motor, rated at up to 48V and 150 amps continuous. I got it used, through Craigslist, from a college student who built those robots that battled each other. He was using this motor to swing a hammer, but it was too powerful, and he kept breaking hammer handles!
Direct current motors are very straight forward. They are easy to control the speed of. Also, batteries use direct current. By using a DC motor, theres no intermediate step of converting DC battery power to AC power to run the motor.
The Briggs motor has eight holes on the end (the face) of the motor to make it easy to mount to a piece of flat steel or aluminum. Some motors have a foot on the bottom of them for mounting, which wouldnt have been as easy to use in this situation.
Permanent Magnet motors tend to be very compact. They create rotational energy (torque) by pushing two magnetic fields against each other. The one magnetic field is produced by current from the batteries (an electro-magnet). The other magnetic field is from mineral permanent magnets. These magnets are much more compact than a second electro-magnet would be, allowing for an overall powerful, yet small motor. The limiting factor in the design is the strength of the permanent magnetic field. Many permanent magnet motors spin equally well in either direction. Just swap the positive and negative battery cables for it to spin the other way. The permanent magnets are ALWAYS magnetic! So dont drop a washer near one of the vent slots, or it will get sucked in and you have to take the whole thing apart to get it out! Since then, I made sure ALL washers are stainless steel (not only are they corrosion-resistant, but they are non-magnetic as well.)
I chose this motor knowing that many other people had used the same one in their electric motorcycle designs.
Permanent magnet motors are generally designed to spin equally well in either direction. If the motor spins the opposite direction of what you intended, all you have to do is swap the two cables. On a large motorcycle, you could take advantage of this with a reversing contactor to have a reverse gear.
Electric motors are rated differently than gas engines are in terms of their power. A gas engine is rated in horsepower with the engine running at nearly maximum speed and fuel consumption (full-out!) An electric motor is rated at how much power is can put out continuously – for hours at a time. So, a horsepower rating between an engine and an electric motor is not apples to apples.
More and more engines are also now being rated in Watts. A watt is a unit of power used. Most people understand watts, as in that a 100-watt light bulb uses more power than a 75-watt lightbulb. It puts out more power (as light and heat) but also costs more on your electric bill.
In electric vehicle design, keep in mind that volts x amps = watts. Also, 1 Horsepower is roughly 746 watts. So, its pretty easy to do some simple math to figure out the power of our motor.
By being connected to four 12V batteries in series, the system nominal voltage is 48V. The motor is rated at 150 amps continuous. 48 x 150 = 7,200 watts. Divide that by 746 (watts to horsepower) and you get about 9.6 horsepower. That doesnt sound like a lot. However, you can pull much higher amperage briefly through the motor – typically three or four times as much. My system amperage is limited by the fact that the motor controller maxes out at 300 amps. That still means we can get DOUBLE the power out of the motor compared to what you might think it can produce, just based on the numbers stamped on it.
Combine that with increased efficiency (by completely losing the transmission) and the fact that you haveFULL TORQUEright off the line (a gas engine has to rev up to several thousand RPM to get into its best power band) and even a compact electric motor has far better acceleration than you think it might.
I later had my cycle tested on a dynometer at a large Harley-Davidson gathering. The cycle officially clocked-in as 12hp. But when the guy first went to ride the cycle up to the dyno, he almost threw himself off with how quick it accelerated!
What other motors might you use in your electric motorcycle? Besides permanent magnet DC motors there are also Series-Wound and Brushless DC motors as well as some new AC motors. Series-wound motors are similar to permanent magnet DC motors. They are bulkier, but produce fantastic torque! You could use a series-wound drive motor out of a junked electric forklift. Do not use a pump motor. Those typically do not have a male driveshaft. Same goes for electric golf cart motors. They may otherwise sound like a good motor for a cycle, but unless you have a way to easily connect a standard sprocket to the motor, they will be a lot of tinkering to make work for your project.( A friend of mine is currently working on designing a kit with a specialty part allowing anyone to build their own electric motorcycle using an off-the-shelf golf cart motor. Look for that in the future.)
Brushless DC and AC motors are very similar. They require dedicated controllers designed specifically for them. If you go that route, buy your motor and controller as a matched set through a reputable dealer.
in general, all these motors are air-cooled, so you dont need a motorcycle with a radiator on it.
For planning purposes, you want to know that your motor will FIT in the motorcycle before you buy it! Made sure to measure the space you have and the physical size of the motor before you buy. If the motor is not in front of you in person, dont worry, most mainstream manufactured motors have diagrams that you can download, that include the physical dimensions. (See Etek_Diagram PDF file attached below.)
Besides the diagram showing physical dimensions, it also lists important information on torque, voltage, RPM, etc. That helps you plan out your cycle design as well.
Once you have your motor selected and in-hand, you need some way to physically mount the motor where you need it to go in the motorcycle.
To do this build an Adapter Plate or Motor Mounting Plate.
I built mine from a piece of scrap 1/4 aluminum plate that I had around. The plate needs to have a hole in the middle of it for the driveshaft to pass through and four holes in the appropriate locations for the bolts to mount the motor to the plate.
The plate also needs mounting points to connect it to the frame of the motorcycle. On this project, I re-used the existing mounting points in the frame of the cycle where the engine and transmission originally bolted in place. Those holes are already just about where I needed them and it meant I didnt have to make any new holes in the frame.
Rather than making a template from scratch, or drilling holes based on careful measurements of the motor, I simply made my own paper template based on the PDF file that I already had of the mechanical drawing of the motor. In a graphic design program, I simply made sure that the measurements on the diagram matched up to 100% actual scale, and printed it out on paper. The motor is compact enough that the whole image fit on one 8.5×11 sheet.
I cut out the piece of paper and then glued it (rubber cement) to the aluminum plate. Using a drill press, I simply drilled holes of the appropriate size (the size is marked right on the diagram!) right through the crosshairs on the piece of paper. That gave me a plate of aluminum with a central hole for the driveshaft, and four holes to mount the motor to the plate. I test-fit the plate in place on the motorcycle, with the drive-shaft hole lining up with the marks on the frame indicating where the chain originally went. I then sketched right on the plate tabs of where the plate would extend to the existing mounting points on the frame – one on the bottom and one on the high side of the back. I will later add another attachment point on the front with an angle bracket.
At that point, I could just put the motor and plate together to confirm that all the holes lined up. I also traced the outline of the motor on the plate.
Once I rounded off all the edges, I put the plate in the motorcycle, and ran threaded rods (3/8 and 5/16, which matched the holes in the frame) through the frame attachment points, through the plate, and through the matching attachment point. Stainless steel nylock nuts and washers went on both sides of the adapter plate and on the outsides of the motorcycle frame. If I ever need to adjust the position of the motor side-to-side, I can loosen the nuts on either side of the plate and move it one direction or the other.
This motorcycle is powered by four off-the-shelf batteries. They areOptima Yellow-Tops, rated at 55 amp-hour capacity, and cranking current of nearly 900 amps. They areAGM- absorbed glass matt. Thats a style of lead-acid battery that is sealed up and the electrolyte is soaked into coils of fiberglass matting. They cannot leak, spill, or slosh around.
While there are other types of batteries available, this seemed to be the best combination of price and performance for my project.Floodedlead-acid batteries are really not acceptable for a motorcycle. Besides being challenging in adding water, the movement and possible tipping-over of a motorcycle would not be good for flooded batteries.
Sealedlead-acid batteries (VRLA) would also be fine, as wouldgels. However, neither of those can crank the power as well as an AGM can, which is what gives the cycle good acceleration. Lithium batteries are excellent for weight, capacity, and power, but are currently only for those with higher budgets. If you use lithium batteries, everything else about the project is the same, except for a different battery charger and a battery management system.
Going back to some simple math, we can get an estimate of motorcycle range. I have four batteries, each of which is 12 volts, but they are wired up in one series string of all four of them, so its really 48V in total.
So, in theory, 48V x 55AH = 2640 watt-hours capacity. 100 watt-hours per mile is a typical ball-park number for energy consumption per mile on an electric motorcycle. (Of course that does vary by weather, speed, riding style, etc.) But this is just a rough estimate.
Just a real rough estimate, but its good enough to say Will this vehicle meet my needs? Will it perform the way I want it too?
In this case, yes. I only live a couple miles outside town, and the next town is ten miles away. I can use this cycle to drive all over locally, and head to the next town over and back on one charge.
In real-world driving tests, the single-charge range of the cycle came to 23 miles if I drove full-tilt, and 32 if I was doing easy acceleration and in the city 25 mph zones.
Lead batteries are NOT light. It helps to make a mock-up from foam or cardboard, so that you have a LIGHTWEIGHT, easy-to-handle version of the battery to experiment with. I like to think of this as the poor-mans C.A.D.
If you are into computer design, there are many great programs out there to help you create 3D images and think in three-dimensional space.Google Sketchupseems to be getting fairly popular. Still, you really cant beat an actual, physical object in your hands. I just prefer something that weighs less than lead.
In my earliest version of the cycle, I had three batteries in it. Then I moved up to four (for more range and higher top-speed.) I was never sure how to fit four inside the frame in a way that fit well and looked good. By using cardboard mock-ups, I was able to experiment with various arrangements of batteries until I found one that I liked. In this case, the fact that I could mount these batteries turned on end allowed me to come up with a configuration that I liked.