Introduction: Lightweight Electric Motorcycle With Bamboo Frame
The main stages for this project are:
- Setting your goals for distance and speed and creating a budget.
- Researching and ordering drive train parts.
- Testing the drive train
- Creating a model in SketchUp
- Obtaining and heat treating your bamboo.
- Hacking apart your donor bike
- Tacking the frame together
- Epoxy-ing the joints
- Creating mounts and attaching the drive train.
- Final parts and safety checks.
Screw driver (Phillips and flathead)
Computer w/ SketchUp
Batteries and charger
Bicycle breaks (front and rear)
Bike wheels and tires (front and rear)
Handlebars and stem
Two switches (one for controller killswitch, one battery circuit breaker Rear sprocket (match pitch with motor sprocket)
Chain (match pitch with motor sprocket)
Step 1: Setting Your Goals for Distance and Speed and Creating a Budget
Setting goals for distance and speed will help dictate your parts and budget. As an electric motorcycle, it won’t be particularly speedy unless you get a very large motor. Realistically, the top speed for this project should be somewhere between 20 and 40 mph, depending on gearing and motor choice. The upside of this is that depending on where you are living if it goes under a certain speed you do not need to get it certified to ride it on the streets.
For our project, we set the goals of a 25 mile cruising range and a 25 mph top speed. Because of some gearing complications we actually ended up with a top speed of around 35 mph.
Our budget ended up being around $1100, including one blown controller and a few tools we didn’t have already. Your budget will most likely be your limiting factor. It will determine the size and power density of your batteries (your most expensive part) and how powerful your motor is. It is important that you leave an extra couple hundred dollars in your budget for unexpected costs, because who wants motorcycle that almost runs?
Step 2: Researching and Ordering Drive Train Parts
Step 3: Testing the Drivetrain
Once your drivetrain arrives, it is important to make sure that all of your parts will work together. Charge your batteries, and then lay your drivetrain out on a table. Use alligator clamps to wire everything up. Make sure that the throttle controls the speed of the motor properly, and note which way the motor spins. Scooter motors are generally meant to be mounted on the left side of the bike, and you’re going to mount the motor pointing to the right like a bicycle chain, so you’ll probably have to switch polarity on the motor. During the wiring stages is when you will worry about what fits, for now we just want to make sure we have all the parts, that they are compatible, and that they work.
Step 4: Creating a Model
First make a sketch, and remember triangles are your friends. Once you have an idea of what the bike should look like, assemble a model. Either make a scale model out of wooden dowels or make one on the computer. Model all your parts accurately and to scale. You will do this to make sure there is spare room for your parts, that there will be a clear chain line, and that your parts will be able to be mounted properly.
Step 5: Obtaining and Heat Treating Your Bamboo
Step 6: Hacking Apart Your Donor Bike
Step 7: Tacking the Frame Together
This step is fairly simple, but extremely important. The purpose of this is to make sure everything fits together, help determine the angles, give you a chance to change things, and make it much easier to epoxy. You will not be able to change the angle of anything once you epoxy it so tacking everything together with hot glue is an important step.
Step 8: Epoxy the Joints
Step 9: Creating the Mounts and Mounting the Drive Train
Step 10: Wiring
Step 11: Final Parts and Safety Checks
At this point, you should be in possession of a running, albeit somewhat uncomfortable, electric motorcycle. It is at this point that we recommend adding foot pegs and a seat of some sort.
Our seat was made by folding rags into the general shape we wanted, and then wrapping the rags with with duct tape. Still uncomfortable, but slightly less so.
As far as safety goes, we recommend a motorcycle helmet (a bike helmet at the very least) and that you probably should avoid riding this in the rain.