How can I add pedals to a motorcycle frame???

I've decided to dive into sort of big project. I just bought a 1973 Harley Davidson dirt bike frame. It's perfect for me. I have a 72v 2500w rear hub wheel with accessories. I think it would be a great conversion project. Only problem is I don't have a license (never gotten one, by choice) so I need to put pedals on it to ride it and not get in trouble. I realize it is not "road legal" anyway at 72v and 2500w, but if I don't go over 20mph where I can be seen and don't act like a jagoff I should be fine. I do not weld, nor do I know anyone who does to weld a bottom bracket onto the frame. Is there a way I could bolt one on somehow??? Anyone ever tried to do this???

Here is a pic of the frame. I think it's beautiful... if you can see passed the rust... lol

that'll be a pretty heavy thing to pedal if anything goes wrong. (probably about like my crazybike2, if not my sb cruiser trike).

i think that pedals or no, you may have trouble with what people see when they look at it; even without the engine it's a motorcycle to the eye, and law enforcement may tend to hassle you about it even if they can't actually ticket you (i don't know the laws there, so they may be able to do that, too). i occasionally get stopped on my crazy contraptions because theyr'e not obviously bicycles, though i have not had any problems because of it (they are legal per current laws here in az).

that said:

if the frame is narrow enough you can cut the bb & surrounding tubing from a pedal bike and then clamp or bolt it onto the mc frame via the tubing. if it's not narrow enough you'd either have to modify the frame so it becomes narrow enough, or you'd need to find a wider bike to cu the bb/etc from (like a fatbike, or some of the crappy scooters that have "show pedals").

but unless you're going to bolt a mc sprocket to the pedal's sprocket (chainring) then you have to manufacture an adapter to mount bicycle sprockets to the rear wheel.

then you'll need to setup a chainline that goes around the frame tubing at all the positions of the rear suspension travel, or add idlers to the frame to keep it off of the frame. or live with the various issues the interference creates.


for the hubmotor wheel, i don't know that specific mc but: unless it is a motorcycle hubmotor, you're also going to have to manufacture adapters to hold the motor axle to the frame; mc wheels are typically a lot wider than bicycle ones, and their axles are significantly larger.


if you have to do that kind of fabrication anyway, i'd recommend instead using the motor inside the frame to drive the wheel via the motorcycle chain as if it was the gas motor--you'd get the benefit of the well-built mc wheel, as well as of being able to gear the motor for it's ideal rpm range vs speed you actually use it at vs the voltage you're running it at.

I'd agree on the too heavy to pedal, but most mopeds the pedals are useless beyond starting the bike. I assume you want a 5,000w motor with a 500w sticker to register it then the pedals become meaningless. Don't build anything so powerful that they KNOW you're cheating on your registration, as Amberwolf says they'll be watching how you ride it.

You need to figure out if a wide pedal crank kit will be enough, or if your frame is wide enough you'll have to make your own. http://www.bikeberry.com/wide-crank-assembly.html https://www.kingsmotorbikes.com/products/wide-pedal-crank-kit-2pc I'd say you want it to connect to a jackshaft that'll drive the wheel from the electric motor by way of a freewheel so the cranks won't keep turning.

If you can find a donor bike that has a wide enough crank set to clear the frame, then you could use U-bolts to bolt it to the plate on the bottom of the frame.
Welding would be better, but if you don't have a welder, bolting is about your only choice. As everyone points out, pedaling will be pretty useless, but if the goal it to have the pedals for cosmetic reasons only, a weak, bolted setup might be fine.

I'm wondering... what if I did a combination of rear hub motor AND a mid drive? I could use the mid drive as a backup to make it easier to pedal if something went wrong with the hub motor. Does that sound like a good idea??? Or possibly a Rubee maybe...???

i can see this project not ending well to be honest its going to attract the law be heavy expensive and have poor range

Well, it is more of a project than something that I would use everyday. I want to restore it's physical features as it was originally in 1973, but add the modern electric features. I may sell it when I'm done. Either way, will be easier if I don't have to get a vin number and register it...

Great post, I hope to revive it. I was thinking exactly that same with with converting a 125cc dirt bike into my own "Sur ron. But everyime I go ready to buy I would encounter road blocks in my head, and the main roadblock was weight and cost. I always told myself I can sell the gas motor and make up some of the money but I never went through with the idea. Then I wanted to find a beefy full suspension mountain bike and convert it with a QS 205 5T but then again I was worried about the wheels I want not clearing the frame. So one day on FB marketplace I found a Sherco 0.5 Trials bike for cheap. Being the "0.5" was very important as it only weighs 65 pounds, the 1.0 model weighs 160 pounds. So at 65 pound compared to the Sur rons 110 pounds it should be pretty close in weight after motor, batteries, controller, 220mm 800 pound shock and disc brake install. Wheel base is almost identical to the Sur ron at 1300mm. I have an old beach cruiser in the garage that im gonna cut the crank assembly out of and weld to the Sherco frame for semi-legality reason. The Sherco frame is chrome-moly and im sure the beach cruiser is mild steel so they should Tig weld fine together. I should be all in for everything at around $1.4k

Don't be a jerk. Register your motorcycle. It has a VIN.

Life for cyclists sucks enough with all the car driving sociopaths. This is another thing they shouldn't have to live with.

I had to look up what a Sherco 0.5 looks like:


You'd need to figure out where to put the battery. Probably fill in the seat area and put a saddle on top of it so you could actually sit on it.

Fair amount of room in the gas tank area. Sherco makes a great bike. I got a larger version of the 05 this past spring. Looking forward to getting same class in electric when available and more affordable. I would not put pedals on it. Leave it a trials bike. Most fun you can have on two wheels my friend! Do what you need to, so the cops leave you alone.

I’m not sure you’re going to find a crank wide enough to clear, and if you did, getting the chain to line up so it won’t just fly off if you accidentally pedal would be difficult without welding to the frame. And you’d likely need to cut up a fat bike frame to do it.

I considered that for a 20mph-max e-moped project, decided against it because of the work, and my project looked exactly like a rideshare scooter anyway. I never had trouble, but I wouldn’t have attempted it with a motorcycle.