Motoped: Motorized Bicycle
Motoped: Motorized Bicycle
Motoped - a DIY motorized bike kit that you assemble yourself using a XR50/pitbike engine and standard mountain bike components.
Motoped - a DIY motorized bike kit that you assemble yourself using a XR50/pitbike engine and standard mountain bike components. Read more
About this project
What is a Motoped?
The Motoped is a motorized bicycle. It uses a Honda xr50 or chinese pitbike engine and downhill mountain bike parts mounted to a custom frame and swing arm.
Why a motoped?
In 2008 when gas prices hit s4.50 a gallon, I began to see a lot of motorized bikes and mopeds running around town. All of these bikes were using 2-stroke egines that sounded like chainsaws on steroids. I thought the forest was being cut down, but no, it was just my neighbors new motorized bike. I thought to myself there's got to be a less annoying sounding (and less polluting) engine than these 2-strokes. I knew that the Honda xr50 engine had been around for 40 years and there was tons of aftermarket parts for it. I just needed a way to combine pedals with it. The Motoped was born.
What do I need to build my own?
At this time, we are only selling the kit to build your own Motoped. We will provide you with a detailed list of off-the-shelf motorcycle and mountain bike parts that you will need to complete the build. The basics are a Honda xr50/pit bike 50-190cc motor, gas tank, seat and a few other motorcycle parts, the mountain bike parts include forks, brakes, wheels, tires, cranks, and pedals. All of the custom made parts - frame, swing arm, jack shaft, bottom bracket, rear hub, sprockets, and exhaust system will be sold in the "Motoped Frame Kit ". For more engine and parts specifications visit motopeds.com
What parts are included with the Motoped Frame Kit? The Frame Kit comes with the frame, swing-arm, sub-frame, jackshft assembly, sprockets, bottom bracket, rear hub, and exhaust system(pipe&muffler)
Motoped Frame Kit details
Frame The frame is made in the U.S., hand tig welded out of U.S. certified chro-moly tubing. Head tube size is 1 1/2" mountain bike. All tank/seat/ body mounts are Honda crf50 style pitbike. Shock mount is 7/8" wide with 8mm(5/16") hole. Frame is powder coated metalic grey.
Swing-arm The Swingarm is hand tig welded 6061 aluminum. Dropout spacing is 135mm with 14mm axle. Standard 51mm ISIS mountain bike brake mount. Shock mount is standard mountain bike 7/8" wide with 8mm(5/16") hole. Shock length is 10.5-11" (267-280mm)
Rear hub This is a custom made rear hub that must be used with the motoped. Rear hub is 135mm wide with 14mm axle. 36 spoke. Left side is ISIS mountain bike disc brake mount, right side is solid mount for sprocket. Hub has sealed bearings and is anodized black.
Jack shaft The jack-shaft is made up of a 3/4" steel shaft running on 3/4x1-5/8x7/16 sealed bearings with aluminum couplings and sprockets. Sprockets are 7075 aluminum and are for #420 motorcycle chain. The sprockets are from Azusa Engineering and can be purchased separatly in different sizes.
Exhaust system This is a custom made exhaust system that must be used with the motoped. Exhaust pipe is 1" outside diameter. Pipe has exhaust port for honda xr50 style port. Muffler is hand tig welded from 6061 aluminum.
The motoped has a patented pedaling system that combines the engine drive with the pedal drive through a jack-shaft located in the swing-arm pivot. This means that the rear wheel drive chain is not loosening and tightening as the rear suspension travels through its arc. Also, this allows for one chain going to the rear wheel unlike most motorized bikes that use two chains to the rear wheel - a separate chain for the engine and the pedals.
Why use a Honda 4-stroke in a motorized bike? The Honda 4-stroke horizontal OHV motor is the most popular and most copied engine in the world. It was first introduced in the Honda mini-trail 50 in 1969 and is still being used today almost unchanged in the crf50. The Chinese have been making copies of the Honda 50 for years now, with all kinds of variations in design and displacement, but all having the same motor mounts as the original Honda. The engines range from 50cc to 190cc. The Chinese copies of the Honda xr50 has spawned a whole group of minibikes called "pitbikes". The amount of aftermarket performance parts for the Honda xr50 and it's pitbike clones is endless.
Mountain bike parts
The mountain bike parts needed for the motoped are Forks, Wheels, Tires, Rear shock, Brakes, Cranks, Pedals, Headset, and Freewheel.
The xr50/pitbike parts needed for the motoped are Engine, Tank, Seat, Plastics, and Throttle.
What does it cost to build a complete Motoped? This depends a lot on the components you choose and where you buy them from. Below is an approximate price list for all the parts required to build a motoped with mid-price range parts from online sources. Buying from your local bicycle and motorcycle shop will be more expensive.
How hard is it to build my own?
If you have both mountain bike and pitbike experience, it's a piece of cake. If you have just mountain bike or pitbike experience, you will need to do a bit of learning on the one you don't know. If you have neither mountain bike or pitbike experience, the motoped may be a bit difficult, and you should probably learn mountain bike and pitbike mechanics before you attempt it.
There are no special tools or machining required to build the motoped, that is as long as you use the correct parts in which the motoped was intended. We have a list of exact part specifications and where to buy them on our website.
Is it legal to ride on the street
It depends on which state you live in. Laws for motorized bicycles vary by state so we recommend reading up on your local laws before hitting the road. If it is legal to ride motorized bikes in your area, it is legal to ride a motoped(with a 50cc automatic engine). In some states, motorized bicycles that are 50cc or under, automatic transmission, and is capable of pedal propulsion do not require registration. In states that require DOT approval for all motor vehicles, motorized bikes are not legal because there are no DOT approved bicycle tires. Some states allow motorized bikes in the bike lane and some don't, also, there is usually a 30mph speed limit on motorized bikes. Some other requirements like headlight, taillight and horn maybe needed, along with proper safety equipment.
Complete Bike and rolling Chassis Parts
This is a list of the parts on the rolling chassis and complete bike. There is a choice between a 50cc and a 70cc engine, even though the buy link says 50cc.
Why kickstarter and what's next
We have been making and selling the Motoped in small quantity for $1500-$1800. To get the price down to a reasonable amount, we need to do larger volume runs. We're hoping Kickstarter will enable us to do a run of 300 or more so we will be able to get the price down to under $1000. The main frame will be manufactured here in the U.S. out of American certified Cro-Moly tubing. To get the cost down to our $970 price, we will have to have more of the components manufactured in Asia, like the Bottom Bracket, and Exhaust system. The rear hub we are already having manufactured in Asia. I do not believe that the quality will drop in the high production run. I am hoping to increase the quality. For example, right now we are not heat treating the rear swing-arm because it's too expensive to heat treat 5 swing-arms at a time, I simply made the swing-arm out of thicker tubing to account for no heat treating. When we do a large production run we will be heat treating the swing-arm. Also, the motoped is made from stock tubing sizes right now, manufacturing in large numbers we will be able to do things like custom tube extrusions, forgings, and hydro-forming.
July: Send out cad drawings of parts (hub, bottom bracket, muffler) to off-shore manufactures to get samples sent back for test evaluation.
August: Meet with US frame manufacturer and begin building welding fixtures for the main frame.
September: Begin frame production. Evaluate part samples from off-shore manufactures and give the go-ahead for them to begin production.
October: Visiting manufacturers and checking parts for quality control purposes.
November: Assembly of parts to make sure they fit together. Packaging and shipping materials.
December: Begin shipping motopeds out.
Risks and challenges
The design is solid, we've been making and selling the motoped in low quantities for 2 years now, and have had very few problems. There is not much risk of the motoped not performing up to it's intended design.
The main risk is that it may take longer to manufacture than we expect and put us beyond the estimated delivery date. The manufacturing process of frame weldments can be tricky to get consistent results due to warping that occurs in the welding/heat-treat procedures. Though I will try to do my best to make this happen in a timely manner, it will be ultimately up to the manufactures to make this happen.Learn about accountability on Kickstarter
Have a question? If the info above doesn't help, you can ask the project creator directly.
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