Introduction: Electric Motorbike

Picture of Electric Motorbike

This project began with a free Razor Pocket Mod Scooter found on the side of the road. Although it didn't run, the frame was in good shape. I decided to use whatever parts I could salvage and combine them with a mountain bike and custom body to build a more powerful (and adult size) electric motorbike. I decided to use a boys 20" bike, so that the wheel size and low profile matched the size of a small-engined motorbike.

Step 1: What I Needed

  • 1 Razor Pocket Mod Scooter (for frame, brake lever, seat, and charging plug)
  • 1 Boy's 20" Mountain Bike (for wheels and tires, brake, freewheel set, shifter, derailleur, front fork, chain, handlebars, kickstand, and grips)
  • 1 1000w 48v electric motor
  • 1 11 tooth motor sprocket
  • 1 48v 30amp controller
  • 4 12v 9ah SLA batteries
  • 1 48v 2.5amp battery charger
  • 1 twist-grip throttle
  • 1 key start switch
  • 1 additional 7-speed freewheel set
  • 1 additional bicycle chain
  • 1 cyclometer
  • 1 handlebar mirror
  • 1 set 12v headlight and taillight
  • 2' angled steel support bar (for extending rear axle and supporting seat)
  • 1 section of 6" PVC pipe
  • 4' of 3/8" threaded steel rod (for rear axle supports and foot-pegs)
  • 10' of 14" width aluminum flashing
  • 20"x14" vinyl fabric
  • 1 can spray glue
  • MANY pan head wood screws and machine screws
  • Various lock nuts and bolts (mostly 3/8")
  • Lots of wood (1x2 and 1x6 boards, and 1/8" veneered plywood for dash and headlight mount)
  • 1 roll of window insulation foam
  • Electrical connectors for batteries and controller plugs
  • 20' roll of 12 gauge electrical wire
  • 3 cans of Spray paint/primer
  • 1 can wood stain
  • 1 can clear coat
  • 1 can polyurethane

Step 2: Tools Used

  • Electric Drill
  • Drill Press
  • Band Saw
  • Dremel Tool
  • Soldering Iron
  • Metal Shears
  • Staple Gun
  • Bicycle chain adjustment tool
  • Various wrenches, hammers, and screwdrivers

Step 3: Disassembly and Fitting the Fork

Picture of Disassembly and Fitting the Fork

The frame on the Razor was in great shape with no rust or damage. I purchased the donor bicycle new ($70 from Walmart). All parts were separated and labeled. Because the Razor used a larger pipe diameter for the front fork, I had to cut the downtube from the Razor and attach it over the bicycle downtube. Luckily, the fit was very snug, so a bit of J-B Weld and several pins worked very well to secure the new tube.

Step 4: Extending the Rear Axle

Picture of Extending the Rear Axle

I used the angled steel pieces and threaded rod to create a longer rear end which could accommodate the rear wheel. Because I wanted to complete the project at home without additional tools, I needed a design with no welding. The angled steel worked out very well. It was easy to mount to the frame and offered mounting points for other parts.

Step 5: Construction of the Body and "Tank"

Picture of Construction of the Body and "Tank"

I know, I know, it's made out of wood. Initially, I wanted to design an all-steel and aluminum frame, but once I decided to use the Razor frame and avoid welding one myself, that plan changed. I used steel for all structural elements, and created the cosmetic structure out of wood. This saved a lot of time and a ton of weight. Essentially, the wooden structure is mounted to the chassis, so the bike feels solid. The Razor frame had quite a few mounting points where the plastic scooter panels had been, so I just needed to create a design which used those points.

I created the "tank" and headlight mount using a piece of 6" PVC pipe, cut in half. Cutting such severe angles in the pipe was a bit tricky without a larger band saw, but I was very pleased with the resulting shape. The tank is also the access point for the batteries and and electrics, so I mounted it using hinges. I cut sections of veneered plywood to create the dash.

Step 6: Cutting and Shaping the Body Panels

Picture of Cutting and Shaping the Body Panels

I initially had trouble deciding how I would cover the body. I didn't want to use wood, and while searching through the hardware store, I stumbled upon rolls of aluminum flashing (ordinarily used for roofing). The aluminum was quite thin and cheap, perfect for my project.

I started creating the panels using sheets of poster paper. Once I had formed all of the shapes and bends, I traced the designs onto the flashing, and cut them using a pair of shears. I then bent and fit the aluminum panels by hand to the frame. This was where lots of finger-cutting and swearing ensued. I finally got all the panels cut and fit, and drilled all the mounting holes for the screws. I wanted the body to look like vintage riveted airplane panels, so I drilled parallel rows of holes along the edges of each piece.

Step 7: Painting and Rebuilding

Picture of Painting and Rebuilding

Once the panels were fitted and drilled, I removed them along with the front fork and rear supports. I painted the entire frame, panels, and tank in glossy black. I figured this was the best color to hide less than perfectly even seams between the panels. I used three coats of paint, followed by two coats of clear coat. For the wooden dash, I stained the panels with Cherry stain, and coated them in glossy polyurethane.

When everything was dry, I reassembled the bike, adding the window insulation around the tank hinge. I also recovered the seat (originally white) in a caramel vinyl, and installed the lights, kickstand, motor, and foot pegs. I also added the cyclometer from my commuter bike once I remembered it could be calibrated for a 20" wheel.

Step 8: Wiring, Building the Transmission, More Wiring

Picture of Wiring, Building the Transmission, More Wiring

Then began the wiring...

I first had to solder electrical connectors to all the lengths of wire. I then connected the four batteries in series with a 30amp fuse wired in. This was connected to the controller, and everything else pretty much plugged into labeled inputs(with some minor adjustments). Because I was using a 48v system with 12v lights, and because I didn't want to buy a DC-DC converter, I wired the lights in series to two of the batteries. They draw so little current that it does not affect power while riding. In the future, if I swap the SLAs for a Lithium battery, this will have to change.

My starter switch still hadn't arrived, so I began working on the transmission. The motor I bought has an advertised max RPM of 3000, so I knew I really needed to scale up the gear ratios. If I didn't allow the motor to spin at least 6(ish) times faster than the wheel in first gear, I risked burning it out. At the same time, I still wanted to use the existing freewheel and derailleur set to change gears. What I decided to do was mount a second freewheel set to the frame. This way the motor goes from an 11 tooth to 34 tooth gear, which then goes from a 14 tooth gear to the rear wheel. The mechanical losses due to this system are higher, but it does allow for high torque and low strain at low speed, as well as the option to change gears.

Once the starter switch arrived, I drilled out holes in the dash for it and the light switch and wired them up. With that, the bike was ready.

Step 9: Completed Project (video to Come)

Picture of Completed Project (video to Come)

I am very pleased with the final results of the project. Already, I can see parts I want to change and upgrade, but as it stands, the bike works very well. Riding position is low (seat height of 26"), but can be adjusted by changing the length of the rear support threaded rods.

The bike can reach speeds of 25 mph in first gear on level ground, and onto a top speed of about 40 mph. Right now the range seems to be about 10 miles. It weighs about 100lbs, so it's not the lightest. A 48v Lithium battery could definitely help the weight and range. That being said, I have it at full throttle most of the time, so it could probably go a bit farther with a lighter touch. Total cost of the project was about $650 (free Razor scooter definitely helped). I ordered all the electrical components from Amazon and TNC Scooters ( Hardware was from Lowe's and Home Depot. The batteries were from a local dealer (but also easily available online).

I hope you enjoyed my build. Any comments or questions are appreciated!


antonio1981 (author)2014-12-26

It's a gratis idea But in Italia is Not possibile to use It on the road

michal154 (author)antonio19812015-03-15

Why You cant use it in Italy?

etriker (author)michal1542017-11-15

In fact you can't ride it on any roads in the US either due to it not having operable pedals. The laws here are simple. Limited to 750watts (1 HP), 20mph, and must have pedals. Otherwise you need a moped license & insurance.

kirama (author)2016-12-23

it real nice and helpful for people with low income like me

good presentation

TheGunNut44 (author)2016-04-24

VIDEO! please

John_Singleton_ (author)2016-02-07

Looks so cool

mskogly (author)2015-12-15

My lord, that was on sweet ride!

GrimRipper1080 (author)2015-07-05

Just wondering, this has been up for a little under a year but there still is no video. I've been planning to build one myself just cause of the awesomeness factor alone. I would like to see a video to see how practical this could be in day to day use. Just a thought.

swm5376 (author)GrimRipper10802015-07-08

Sorry about that. I graduated and moved out shortly after completing the project, and unfortunately it is still sitting in my parents' garage. It would have been smart to get a video before leaving, but hopefully I can make one soon.

DerrickDIY15 (author)swm53762015-12-05

Is it for sale? lol

Snidely70448 (author)2014-10-19

"I purchased the donor bicycle new ($70 from Walmart)."

Check out Goodwill or a Habitat for Humanity Re-Store. They almost give these small bicycles away because kids are always outgrowing them, and most parents prefer to buy new.

wgasser (author)Snidely704482015-04-16

Really nice bike!!! only one question. what is the name/ style of the bike from Walmart? I can't seem to find them any where. thanks

gweeds (author)2014-10-20

Hi there, looks good!, but would you not have been better to stick that mega range cluster on the back wheel and do away with the intermediate gears? I would hate to think how much they twist out of place under acceleration. Curious as well with that short chain setup, and one cluster running in reverse direction, does the chain hop up on the middle cluster as it hops down on the rear?

imitt12 (author)gweeds2015-04-10

There's only one shifter. He's using the front cluster for gear reduction.

stoobers (author)gweeds2014-10-20

"Intermediate gears" are often necessary to match the torque range of the motor to the driving speed. If the motor needs a 15:1 reduction, and low gear on the bike is 1:1, even the lowest gear on a bicycle is much too high. If you get rid of the intermediate gear, the low gear may end up being a sprocket the size of the rear tire!

If you look at a razor scooter, you will see a tiny rear tire and a sprocket the size of the rear tire.

If you get a motor wound for lower speeds, it runs at a much higher current and blows off much of the electric energy as heat, so a "jackshaft" is more energy efficient and simpler.

lowpro (author)2015-03-14

Really cool.

washingtonboy11 (author)2015-02-21

Do you have the specific measurements??

jscanlan (author)2014-10-21

Nicely done. There is aluminum skinned corrugated plastic that might be good to use for panels.

Blaise_Gauba (author)2014-10-21

Yes. Really nice work! Beautiful build. I wish I understood electrical stuff. I can solder...wire stuff, do wood working, even weld, as I have been a prop maker in Hollywood since 1983...but understanding electrical diagrams is confusing to me. I guess it's just something one learns from doing. I love your electric bike. I am seriously going to think about a project for myself to do building something like this. Excellent design you came up with too. Vintage looking. Too cool.

milesnorth (author)2014-10-20

This looks great. I have a razor that is working and have wanted to convert my daughters bike to electric. Any thoughts on this? Can I use the working scooter parts and somehow make them work with the bike? (obviously not a pro). THANKS.

Opus the Poet (author)milesnorth2014-10-21

Using existing scooter parts will work, but adaptations will have to be made. The motor will run too fast at the higher voltage but you could just stay with the same voltage and get bigger batteries instead of buying 2 more batteries. The existing drivetrain in the Razor uses a different size chain than bicycles and needs to have a ratio change because of the bigger wheel for the bike so remounting the motor to drive a jackshaft with the scooter chain and then driving the freewheel on the bike wheel to get a wheel speed at the rim similar to the scooter speed will take care of that problem. Just measure the scooter tire (you can use a ruler from the side, it doesn't need to be super accurate) and the bike tire and make the ratio between the sprocket driven from the scooter's motor and the sprocket on the bike tire close to that.

phugedaboudet (author)2014-10-21

love the retro look. Only thing it needs to be "perfect" is a different fork. Something like an old Schwinn springer type or repainted old Girvin/Proflex.

you'd have to redo your control panel though.

PhilippeG1 (author)2014-10-17

Pour rouler plus longtemps augmenter l'ampérage, le voltage c'est la puissance, l'ampérage la durée.

To ride longer increase the amperage, voltage is power, amperage time.

crickleymal (author)PhilippeG12014-10-17

Surely you mean to ride longer DECREASE the amperage. Batteries are rated in Amp hours so the more amps the less time and vice versa. Power is Volts times Amps.

woodNfish (author)crickleymal2014-10-21

I think Philippe is referring to the power used and you are talking about about battery reserves - two differnt things, and you are both correct.

DavidM15 (author)crickleymal2014-10-19

He is talking about batter size increase the amperage of the batteries in use will increase riding time. He is using 4 9ah batteries so he more the likely has then in a series/parallel which gives him only 18ah storage. increase that and he WILL get more riding time!

Kevanf1 (author)crickleymal2014-10-19

Forgive me if I am wrong with this. I have always believed that the higher the amp hours a battery is rated at then the longer one has in cranking time. This is obviously applied to a fossil fuel engine. It is turning an electric motor albeit a starter motor though. I drive a Land Rover and always use a high amp hour battery to give a longer cranking time especially in the Winter. To my feeble mind this means higher amp hour equals longer running.

Rynzlery (author)PhilippeG12014-10-17

Non. augmenter l'ampérage donne plus de couple au moteur et augmenter le voltage donne une vitesse de rotation plus élevée. il faut prendre une batterie avec plus de mAh pour rouler plus longtemps.

handymandavebritain (author)2014-10-21

Cheers, Great project, Classic look, visually it resembles my old Fathers 1930's James 98cc motorbike in family Album. I think many would need the drive / gearing clarifying if never involved in pedal bikes.

IdahoDavid (author)2014-10-20

That is a classy looking design and well-executed project. I wish commercially offered electric bikes looked this good.

guruji1 (author)2014-10-19

Hi thanks for sharing this. Yes as you've said regarding adding another tooth gear there would be more losses. Could this be done if you tried to increase gears instead of adding another tooth wheel? and doing a circuit for the motor so it do not spin very fast? Thanks

swm5376 (author)guruji12014-10-20

A similar question to this is answered much better above, but basically I wanted to use the bicycle freewheels, and those don't come much larger than a 34 tooth sprocket. That ratio is still far too low, so the additional sprocket was a jackshaft to triple the increase in gear ratios. It's not a perfect system, but definitely the most energy and cost efficient I had available. In the future, I'd like to add a rear hub with internal gears and avoid the derailleur mess.

Electro-cute (author)2014-10-19

фантастический ! How many hours and how long total time did it take to complete your e-bike> I envy your mechanical aptitude. I just wish I could get some help on something like this ( I own / ride a ZERO S zf11.4 ). Would you ever consider working with other bike enthusiasts at a DIY Faire to run a Make-And-Take Workshop ? Will a complete parts kit be forthcoming ?

swm5376 (author)Electro-cute2014-10-20

It took me about a month. I had just graduated from college and was job searching at the time (thankfully employed now). I have never been to a DIY faire before. Where/when is it? As for the parts kit, there are still some things I want to change on the bike, as well as do more long term testing. Hopefully, I'll have one soon though.

Everlong (author)2014-10-20

Pretty badass! :D

jongscx (author)2014-10-19

Wait, so is the 1000W motor from the razor scooter or was that bought separately?

seanthesheep101 (author)jongscx2014-10-20

it was bought seperately

llopez-garcia (author)2014-10-19

Hey congratulations on your instructable!

This is a really cool bike!

However the way you repositioned that rear axle does not look safe at all. Without going into too much detail, the way you have it set now will cause excessive bending moments and will likely break something.

To fix it, your threaded rods should be attached further forward at the top of those vertical tubes and your angle iron should be attached further forward at the bottom of the vertical tube.

Hope this helps!

studleylee (author)2014-10-19

I really like the way you built up the body panels and construction. Very cool look acheived!!!!

Ricardo Furioso (author)2014-10-19

Great instructable. Thank you for sharing. Please. More.

chrisnotap (author)2014-10-19

That is frickin cool. What a sweet job you did. I have 3 rules, salvage, salvage, and salvage. You followed all 3! Love it!

sabr686 (author)2014-10-19

Great ible! I like the way you used the body to streamline and tuck in all the working parts. Have you thought about possibly adding front and back fenders? Just something in the floating, minimalist style. Think motocross bikes. Thanks again.

RG_on_the_move (author)2014-10-16

I love the look - it's a café racer! Quite an impressive build. Congrats!

was thinking the same myself!

ggarnier (author)2014-10-19

You gotta love Autocorrect! Although for me this project probably would prove intractable.

splodgie (author)2014-10-19

Hi, Nice looking Project, Just be aware of the Law in the UK on Electric bikes on the road, pedals and speed play a big part in classification. Get that video up, I need to see you in action on your lecky cycle.

hammermomma (author)2014-10-19

I was very inspired by your imagination, creativity and your thought process in figuring out how to proceed. Your willingness to commit attention to a high level of detail is what has made this beautiful. I am sure you learned a great deal in the process. Keep at it. You are headed to bigger things!

v30003v (author)2014-10-19

Kevanf1 (author)2014-10-19

What a fantastic project, well done :) May I offer a couple of ideas for the future? You don't mention if you've used LED lights? If not then these would save some (a fair bit possibly) of the power draw. Next, if you can get to know somebody who can weld aluminium you could make a much lighter frame. Use lighter tubing allied with some strategically placed gussets (triangular sections) to spread the stresses in order for the tubing to withstand the strain. You'd need to keep an eye on things after every ride just in case the weight saving went a bit too far and you ended up with cracks :( Good luck and well done again :)

gnomedriver (author)2014-10-18

Great looking machine.

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