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bennelson 01-09-2008 09:54 PM

Electric Motorcycle conversion
1 Attachment(s)
EDIT: January 2018. I have posted ALL of my original BUILD YOUR OWN ELECTRIC MOTORCYCLE DVD as YouTube videos. They are divided into sections. The following playlist is the full and complete collection of the OFFICIAL video that I made based on this project.

[Author's note, added September 2014.]
It's been going on seven years since I built the motorcycle. I've learned so much working on this project, leading me to also build an electric car and a hybrid. I also now give presentations teaching people how to build their own electric vehicles. When the motorcycle was complete, including a 48V battery pack and welded battery rack, I created an instructional DVD set teaching how anyone can build their own. If you are interested, please take a look at the DVD on my blog at: It's also now available as a digital download as well.
Have fun reading this thread. It was a blast to learn how to build an electric motorcycle!
-Ben Nelson 9/24/2014

PPS: Apple computers discontinued their web page service, simply deleting the original web page that I created on this project. Because of that, there are some broken links and missing images in this thread. For the latest on this project, please visit

(Begin original post)

Last summer, I converted an old, non-running motorcycle to run on batteries and an electric motor.

It has sort of been a tinker-along-the-way project. I have never had a motorcycle before, but always wanted to learn to ride. I also hated how loud motorcycles are. (Shouldn't they call them ENGINE-cycles!?!?)

I had tinkered around with an electric bike, which was great fun, but then I wanted more speed and shocks. I was also suprised at how car drivers behaved around the electric bicycle. People would pull out right in front of me not realizing how fast I was going.

I sort of figured that if I wanted something that was faster, better suspension, and street cred, that thing would be a motorcycle.

I took a good look through the Austin EV Album to see what parts people commonly used on small projects and e-mailed a few folks for advice.
I picked up a copy of the "Secrets of EL Ninja" book/plans and used it as a rough basis for the conversion.

I wanted to do eveything as cheaply as I could, but I did buy a new Alltrax controller and later, new Yellow Top batteries in place of the tiny AGMs I was using from the bicycle.

The cycle is completely street legal, licensed, registered, and insured.

It was only designed as a short-range/limited speed project, mostly because of what I could fit in it for batteries. It goes up to 38 MPH and the longest I have ever taken it is about 16 miles, with just a little break and tiny bit of charging between the two 8 mile one-way trips.

Both my office and the grocery store are only about two or three miles away each, so even this limited range is plenty.

It's a blast to ride. Easy to steer. No clutch, no engine to kill or restart, just twist the grip and go. It is also quiet. There were a few times I would just hop on and zip off to the grocery store. When I got back, my wife would never know I left because the thing is so sneaky quiet. (yeah yeah - loud pipes save lives. Don't get me started. I may just have to hook up an iPod running engine rev noise or stick a baseball card in the spokes. Maybe use a bicycle bell like on that one crazy Commuta car.)

The motorcycle is stashed in the garage for the winter. I would like to eventually work on a cheap, simple, 4 wheels and a roof vehicle for getting around in non-motorcycle weather. (Yes, another Forkenswift....) I am in Wisconsin - motorcycle season isn't that long.

So basically the cycle runs at 36 volts - I would like to bump it to 48 sometime, just need to find space for one more battery...
It goes 10 to 15 miles on a charge which uses about a kilowatt. That comes to about a penny a mile. I figure if gas is $3.00 USD per gallon, that means I get 300 miles per gallon! (I've also done the math completely based on energy content using a conversion from M.I.T. When I did that, my first ride clocked in at 321 miles per gallon equivalent.)

SVOboy 01-09-2008 10:12 PM

Sweet job! I demand more pictures...I'm extremely jealous...


bennelson 01-09-2008 10:47 PM

3 Attachment(s)
I spent about $2000 on this project all together.

$100 for original cycle
$500ish for motor (used on Ebay)
$300ish for New Alltrax AXE 48v 300 amp programmable controller
$160 EACH for 4 Optima yellow top 55AH batteries.

I am also including in this total cost, a motorcycle safety class, new helmet, a year of insurance, lots of little trips to the hardware store, etc.

I am still trying to figure out how to fit that last battery in there.

Here are a few more photos.

bennelson 01-09-2008 10:56 PM

Here is the link to the info I have posted on the EV Album.

MetroMPG 01-09-2008 11:39 PM

Awesome. Thanks for posting that.

Ben's site is cool. More pics & info, neat design. Check it out:



It goes 10 to 15 miles on a charge which uses about a kilowatt.
Your 15 mi / kWh = 67 wH per mile. Nice!

The best I've achieved on a charge cycle with the ForkenSwift is 311 wH / mile.


Question: what type of DC/DC converter did you get? We have one but haven't installed it yet, partly because of winter, and partly because it didn't come with installation instructions (but looks similar to yours with the pins sticking out the back).

If all you need is short range & 35 mph, have you considered shopping for a Citi/ComutaCar? Or are you also looking for another project?

MetroMPG 01-09-2008 11:44 PM


Originally Posted by bennelson (Post 4758)
I am still trying to figure out how to fit that last battery in there.

  • If you know someone who can weld, I've seen people reshape the frame in such a way that you could put another one ahead of the lower single battery.
  • Or, you could do battery "saddle bags", gomi style. (You have seen the gomi bike, right?)


MetroMPG 01-09-2008 11:47 PM

PPS: you know to keep an eye on your ETEK brushes, right? I've read they wear quickly compared to most motors, and if you let them get too low you can damage the commutator.

Silveredwings 01-09-2008 11:54 PM


Originally Posted by MetroMPG (Post 4772)
Or, you could do battery "saddle bags", gomi style. (You have seen the gomi bike, right?)

" butta" :thumbup:

bennelson 01-10-2008 12:24 AM

I would rather stay away from saddle bags. for one thing, it means you need to add two batteries, and I only need to fit one more.

My controller only supports up to 48 volts, so I max out at four batteries anyhow.

Since the cycle is working and registered, I don't have to worry about a state trooper inspection or anything. Maybe I could look at welding and bending the frame. I personally don't weld or have a welder. I would rather not pay a professional welder either.

Hmmm... which of my friends has a welder...

If I do any welding on this, I would also do up some real battery mounts at the same time then. Plenty of bed frames down at the local thrift store.

Now if I can locate a cheap 72V controller, I can add the 4th batt AND do saddle bags.

No I havent' checked the brushes lately. I will have to do that in the spring before I get riding again.

Daox 01-10-2008 09:38 AM

You could remove one battery from the engine area, move it to a saddle bag, then add the 2nd saddle bag for 4 total. Or, you could ask me to help out and I could probably take care of that welding for you. I'm no professional, but I can put two pieces of steel together (some of my work). I doesn't look like it would be hard to extend the very bottom a few more inches for another battery to slide in there.

bennelson 01-10-2008 10:10 AM

Hey Daox,

Yeah, maybe we should have you come out sometime and take a look at the bike and see what it would take to bend/weld another battery in there.

MetroMPG 01-10-2008 11:02 AM


Originally Posted by bennelson (Post 4777)
No I havent' checked the brushes lately. I will have to do that in the spring before I get riding again.

One eBay ETEK seller reported that the motor ultimately didn't do well in the golf cart segment for that reason: brush maintenance (and motor damage where inspection was neglected). Very low maintenance is supposed to be one of the selling points of electric motors, after all.

My favourite ETEK application is still the electric 5th wheel on a Honda Insight.

bennelson 01-10-2008 04:55 PM

3 Attachment(s)
Here is some infor on the DC/DC converter I am using.

It's an Artesyn BXB100-48S12FLT.

If you scroll back up this thread to the photos I posted, it's the little black rectange in the middle of the piece of plywood. That was when I just had it mounted up for testing.

I bought it on Ebay. Price was $10. Seemed like a good deal, so I bought 2, in case I fried one while tinkering with it, or for use on another vehicle.

The fine print on the side lists it as 36-75V in, and 12V 8.3A output.

So, it looks like it's a 100 watt converter. I have heard that headlights are about 55 watts, so it's enough to run the headlight and taillight and brakelight. I have been running a 36 volt system and no accessory battery, the lights and all run straight off the power converter.

The only problem I have had so far is that after a long ride, my system voltage can drop to 33 volts under load - Going up big hills, or pulling away from a stop too fast. This converter stops working at 33V or under. It was only a problem the one time, coming back home at night on a relatively long ride.

If I fit another main battery in my cycle to raise system voltage to 48V, this would no longer be a problem at all. Otherwise I think I could add a small battery to run the lights from and have the dc converter top off the battery.

The converter outputs 12.5 volts. I know that's not enough for charging a 12V battery. There are a few pins on the converter that appear to be for adding a pot that can change the output voltage. I think I could tinker with it and make it output a higher voltage for charging.

I had NO documentation for the DC/DC converter. It took me a while to figure out which pins I had to connect to what to make it work. Besides the obvious Vin and Vout, it also had RC, CASE, +SEN, Vadj, and -SEN pins on it.

I have a switch on my control panel that turns the DC/DC converter on and off. It is totally seperate from the propulsion system, so the motor can be safety'ed off, but I can still turn the lights on or use the horn.

Right now, there is no key for the bike other than the big red emergency disconnect. If the cycle is parked, there is nothing stopping a person from turning on my lights and draining the batteries.

I plan on eventually adding a keyed electric switch that will control a contactor for the motor and power to the DC/DC converter, similar to having an ON and ACC setting in a car's ignition.

My tachometer is useless as it originally was mechanically connected to the engine. However, it does have a light for the Brake and one for OIL.

I wired my brakes up so that the the BRAKE light goes on when ever my brakelights do. I know that is how it's supposed to work, but I had to modify a few things when I moved the rear brake to a hand brake.

I wired up the OIL light to an output from the DC/DC converter. So, it's just a big ON light. When it is lit, I know the DC converter is working right, my brakelights will light up, etc.

I would like to eventually convert the tachometer into an ammeter. I think I could just pop one of the right size right into the tachometer housing. If I was really clever, I could scan the tachometer, pull it into photoshop, mess with it to make a ammeter scale, print that out and fit it into the ammeter. Then I would have an ammeter that would look "factory original".
Click on this link and scroll about two thirds down for a better example of what I am talking about:

In some photos, the bike's gas tank is green, in others, it is white. When I got it, it was silver/primer gray.
I originally hit it will the green, just to make it a little different - yes, a GREEN vehicle.

Later, I thought I would paint the tank white, and put black spots on it like I did for the paintjob on my old Chevy/Geo Spectrum. Unfortunately, a cow-spot pattern needs a bigger area to look right at all.

I am now leaning towards a really right yellow. It would match the batteries and be highly visible, a good trait in a small, quiet vehicle. I could still paint green lightning bolts over the top of the yellow, or maybe just one of those static electricity logos.

Anyhow, I started scraping the paint off the tank a few weeks back to get through the eight layers of paint that are on there. Should save some weight too. I have already cut the bottom out of the gas tank. It makes a great spot for the charger - I can pull the plug out through the gas cap.

bennelson 01-10-2008 06:06 PM


I just checked the front of my Kawasaki Repair Manual. It says the original KZ400 (mine was the 440) weighed 375 lbs.

I weighed the cycle when I had the small batteries in it and it was 400 lbs. I am really supprised that an Etek and 3 18AH SLAs weigh more than the engine, transmission, and mufflers of the original.

The specs on the Optima Yellow Tops say 43 lbs each. I think the original small batteries all together weighed a little more than one yellowtop. I am guessing that the bike currently weighs around 475, which would put it exactly 100 lbs over original stock weight.

The manual also says the fuel tank held 17 liters (including reserve). If gas weighs 6.25 lbs/gallon more or less, then a full tank of gas weighs about 28 lbs.

The weight of the batteries is LOWER than the original gas tank and even with where the engine and transmission were. Center of balance seems pretty good.

MetroMPG 01-10-2008 10:25 PM

Thanks for the DC/DC info. Sounds like you got a better deal than I did. I know if I dig around the web I could probably find the documentation I need. Mine's a VICOR, I believe.

Re: weight. That's a good point - you've got good weight distribution with the batteries where they are now (vs. in the gomi saddle bag location).

Considering that, I think it makes sense to see about getting someone to help you mod the frame to put the 4th batt with the others.

Daox - you're a cool guy for offering!

bennelson 01-22-2008 11:15 PM

Any other questions or comments on this?

SVOboy 01-22-2008 11:52 PM

I still think you should post the advice you pm'd me the other day, :)

bennelson 01-23-2008 12:25 AM

Here is some general advice I gave out for anyone considering doing a gas to electric motorcycle conversion:

Originally Posted by bennelson
For a motorcycle:

Make sure it has a clean title! You want something that you can register THEN convert. Makes it a lot easier.

In Wisconsin, the "Antique" and "Hobbyist" plates apply to motorcycles more than 20 years old. The Hobbyist plate worked best for what I was trying to do. The cycle I bought was over 20 years old.

Sizewize - you want something big enough to hold batteries, but not so big and heavy that you have to push extra weight around.

Make sure it has two down pipes on it, so you can build a platform to hold batteries on it. smaller motorcycles only have one down pipe, like on a bicycle.

Mine was originally a 440cc engine. The cycle is a medium size and could seat two.

The Japanese make good motorcycles. Apparentyly there was a line of motorcycles known as the "superbike" where pretty much all the parts were practically interchangeable between Honda, Suzuki, Kawasaki, and Yamaha.

Crotch rockets are supposed to make good conversions, because they have a strong, lightweight aluminum frame.

I strongly suggest looking at every motorcycle on the AustinEV site.

Also, "Secrets of EL Ninja" is a pretty good book/plans to have before you do a conversion.

This was my first motorcycle - gas or electric. I bought it with a dead engine and no title for $100 out of a guys garage.

Best thing for you to get is a cycle in very good condition except for a dead engine.

Mine had a really bad wire harness that I had to totally rebuild - I would not do that again!

Hope that gets you started.

Feel free to ask other questions as the need arises.


MetroMPG 01-23-2008 08:17 AM

That's an a really good checklist. No doubt it'll be useful to someone looking to do this.

Stan 01-23-2008 12:04 PM

Good stuff, Ben...thanks! :thumbup:

Having had a lot of bikes over the years (I got my first m/c 39 years ago), and restored or modified a number of vehicles, I'd like to stress a couple of points Ben made.

First, GET A TITLE! A title-less vehicle can be a nightmare to register in many States. Wisconsin appears to be fairly accommodating, but in many States it borders on the impossible. If the seller tells you he lost the title, simply ask him to get a replacement from DMV. In every State it is far easier for him to do so than the buyer. If he won't or can't, keep looking for another bike.

Ben laments the sad state of the wiring harness on the bike he bought, and how much work it took to fix it, so here's my advice. Buy a bike that runs! You can check and confirm the condition of every component of a running bike (wiring, brakes, instruments, etc.), but are taking a real crap-shoot with one that doesn't. A running engine (even if thoroughly worn out) has some residual value, but one that does not run at all is near-worthless scrap. Recoup some of the extra cost of a running bike by selling what you don't need on ebay or craigslist. It'll be worth it in the long run.

Thanks again, Ben!

dcb 03-06-2008 06:50 PM


Originally Posted by bennelson (Post 4834)
It makes a great spot for the charger - I can pull the plug out through the gas cap.

LOL, nice touch! :)

bennelson 03-19-2008 09:06 AM

Gas tank Repaint
I repainted the gas tank this last weekend

I didn't really like the white. It looked like a really lame police cruiser. I tried white because I was thinking about a cowspot design, but that really wouldn't have worked very well on such a small area.

I stripped and sanded down to the bare metal. There must have been 6 layers of paint on there, plus bondo filling in dings and cracks!

Looked pretty cool as brushed steel like that. I half-considered just clear-coating it!

I painted the tank hi-viz yellow. It's easy to see and matches the Yellow Top batteries.

Heres what the cycle looks like right now with the yellow tank.

I haven't bothered to re-paint the plastic triangle trim pieces that go in back (the white things) I usually don't have those on anyways, but will paint them to match whatever color I end up going with.

I sort of think I like the metalic green (which can be seen earlier in this thread) the best.

If I didn't like the way the yellow turned out, I could just use it as the primer for a green top-coat. If I masked off part of the yellow, I could make a pattern in it. Like yellow lightning bolts on a metalic green tank!

Last Friday, I took the motorcycle down to our local electric utility. I talked for a couple hours with the guy down there about renewable energy, solar, net-metering, etc and showed him the cycle.

When I was leaving, it was end of shift for linemen. There were 5 or 6 big, burly electricians standing around the cycle. As I was walking up, I could hear them say "Look, that's an electric motorcycle", "Anybody know who it belongs to?", "Huh, well look at that..."

I showed them how it works, where the charger was, and did a test run in the parking lot. They seemed pretty impressed by the acceleration and quietness.

It's really fun when you get people's interest like this.

Tonight, there is a local "Green" meeting going on at the library. Part of the discussion is going to be about NEVs.
If this isn't a good night to bring an electric vehicle down to the library, I don't know what is. Just hope it doesn't rain or snow tonight!!!

SVOboy 03-19-2008 10:07 AM

Wow, looks seriously bling! I'm excited for you, :) (meaning, I wish I was riding the bike instead of you)

MetroMPG 03-19-2008 10:13 AM

It's cool that you're doing the "outreach" part of owning an EV.

Aside from the EV Expo in Ottawa last May, the closest I've come to doing that is showing the ForkenSwift to a few different people who read the thread and contacted me, asking to come look at it.

Plus a week or so back, I stopped in at the forklift place where we bought the lift truck & showed it to the guys there. Our city has a fairly large car show (150-200 vehicles) in the summer. Ivan & I were debating whether we'd want to enter the car in it or not.

Anyway... I like the yellow tank!

bennelson 03-20-2008 06:28 PM

Showing off at the library was fun.

Found another good reason not to ride motorcycles at night though. DEER!

Had one run right in front of me on the ride home!!!!!

Anyways, round trip was exactly 5 miles. According to the Killawatt, I used .57 KWH of energy to go back into the battery. My cost of energy including tax and renewable energy surcharge comes to 11 cents per kilowatt hour.

That means it cost me 6.27 cents to ride to the Library and back.

Based on current price of gas, that's about ten times less than it would have cost to drive my car the same distance. More actually, because I get below average fuel economy with a cold engine only going 2.5 miles each way.

Although if I create an artificial "MPG" based on cost of gasoline vs electricity, this last runs comes to 263 MPG. I will have to check the brake, it was dragging a bit.

Calculations make the cycle's last run come to 114 watt-hours per mile.

Doing the math to kilowatt hours to BTUs to a gallon of gasoline (I was using 125,000 BTUs to gal of gas) comes to 321 eMPG!

Anyways, even if the cycle got terrible economy, it's still a blast to ride!

PS: after entering this last charge, I had to change my signature banner from the Dodge to the Cycle. That way I get Hypermiler status! Guess I just have to ride the cycle a lot more!!!

sharp21 03-22-2008 05:16 PM

Here are some sweet conversions:
Couple of real nice streetbikes & a supermoto.
If you check the parts page, you can get a Full conversion kit with the e-tek for $1k

MetroMPG 03-22-2008 05:48 PM

Is it motorcycle weather already where you are?

I saw two out last week: one dodging ice clumps in the road, the other a Hell's Angel pulled over by a cop.

bennelson 03-22-2008 05:59 PM

It is motorcycle weather in that if there is snow on the ground, but it is sunny, and the roads are fairly clean, you will see guys out on motorcycles.

They may be wearing snowmobile suits, but they will be out there.

I have been out on my cycle twice so far. Short runs. I get cold fast.

MetroMPG 03-22-2008 06:03 PM

I got cold riding when it was 20C out. :P

bennelson 03-23-2008 05:45 PM

Went for a short ride this afternoon (Easter Sunday!)

34 degrees F, lots of snow on the ground, but Sunny!

I have noticed that my speedometer doesn't always work right. At low speeds, the speedometer doesn't work at all.
When I get to 25 MPH or so it kicks up to whatever speed I am going, but then seems to stop working again anytime I get back down to 15 MPH or so.

That means the trip odometer isn't real accurate because is isn't logging my distance during all the slow speed parts of the trip, right?

I do have a pocket-sized hunting GPS I could use sometime to compare the speedometer and odometer with. I might even be able to figure out is there is a more-or-less constant % difference off for future calculations?

If anything, I have been going farther than I thought. Therefore, any miscalculations for fuel economy should be in my favor!

Need to talk to some real motorcycle people sometime. I could use a hand tweeking the rolling resistance on the cycle and swapping out the new tires I have sitting in my garage, just waiting to go on this thing.

MetroMPG 03-23-2008 07:56 PM

Any plans to shoot a vid showing off the bike this spring? Hmm? :P

sharp21 03-23-2008 08:15 PM

Where is your speedo getting its reading from?

bennelson 03-23-2008 08:40 PM

I am planning on taking the cycle to the Milwaukee Hybrid Group meeting in April.

That might be a great place to shoot video. Otherwise at least if we get some good weather first, then I can shoot some video.

The cycle is using the original speedometer. It has a cable that runs to a connection directly on the front wheel hub.

Ryland 03-23-2008 10:13 PM

often times the speedo does what you are talking about simply because it's sticking, if you can find some spray graphite, you should be able to fix it by pulling the speedometers apart just enough to get the spray can straw in there, spray around a bit, and close it up, they are of course designed to keep it sealed so people can role it back to reduce the number of logged miles, but spray graphite is amazing stuff, it's mixed with alcohol so it dries to a nice slippery film as you don't want anything that will attract dust.

I had my scooter out Thursday for a while, filled it up with .41 gallons and put a wire basket on the rear rack, looks much better then a milk crate and holds stuff nearly as well.

sharp21 03-24-2008 05:35 PM

Another good way to lube your cables is to unhook the top end of the cable, poke it through a ziplock bag, tape up around the hole for no leaks, put some oil into the bag, set it & forget it!
The oil will slowly seep through the line. When doing your brake lines you can pump the brake a bit too.

bennelson 03-26-2008 06:51 PM

Here ya go. First video. Nothing much, just shows how the contactor I added works.

Someday I will get around to making a real video


TomEV 03-26-2008 07:04 PM

Your odometer should be working as it is connected directly to the speedo cable by gears. The speed needle can stick - typically the only thing dragging it forward is a magnet at the end of the cable that 'pulls' a metal cup attached to the needle inside the case. Sometimes they stick due to old grease that builds up a small speed bump. Should be easy to clean/relube if you can get the case open.

Stan 03-26-2008 07:10 PM

Nice video, Ben...thanks! I'm a real "how it's made" fan, so I like vids that show contactors and other such mechanical niceties.

I'm also hearing impaired, so can't "hear" the bike because of the music (perennial problem for me...). Would really like to see some video without music so I could come closer to appreciating how quiet your bike is.

Thanks! Stan

bennelson 03-31-2008 08:10 PM

Another article on the cycle

Hey Everyone,

There is an article on HellForLeather about my motorcycle.

See it here:

Stan - note taken about sound. I will be sure to do a "no background music" section when I do a real video about the cycle.

MetroMPG 04-01-2008 09:47 AM

That's an awesome writeup! Congrats.

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