DIY Road Legal Motorbike

[CDoherty95]

Hey y'all

I've had this idea for a while, but it seemed that whenever I'd try to do it I always faced some obstical that forced me to stop.

Now however I'm trying it. I've always been fascinated with motorbikes,mainly Harleys. Around Christmas of last year I began toying with the idea of fitting a gas engine from a lawnmower,chainsaw or weed wacker. Last weekend I put that idea to paper, and within three hours of deciding on this project bought a bike.

The badge says it was made in west Germany, so it's atleast 25 years old. And because it's German it's built like a tank. Unfortunately I found this out the hard way after I had broken seven drill bits trying to drill holes into the frame for supports and mounts.

I swapped out the original forks, which were designed to hold a 24 inch wheel,with a set of suspension forks which are designed to hold a 26 inch wheel. I want the bike to have a chopper kind of look, so I turned the forks around the wrong way so the front wheel sticks out further than it originally did.

It also came with a rear rack. This is perfect for my design because I'm going to mount the engine on the rear rack, and have a chain going from the rear wheel to the engine.

Here's a picture of the bike in it's current state. You can see how far out the wheel is. I've yet to find an engine, but still have loads of numbers to call.

[RogerDuke]

This brings back memories. When I was a kid we had those bikes with the banana seats and high handlebars. We used to put two forks on the front end to make it look like a chopper. One kid even used three. They looked pretty cool but didn't steer well and you sure couldn't make a sharp turn. Mine was blue and the second set of forks were white. (Dukes hadn't came out yet or it would have been orange) My cousin put a steering wheel on his bike. Sadly, I inherited that because he was killed in a car accident at 16. It's still in my basement and is my favorite possession from my childhood.

[CDoherty95]

This brings back memories. When I was a kid we had those bikes with the banana seats and high handlebars.

Oh a banana bike? They're kind of like the Raliegh Choppers. I don't know if they're big over the pond but in Ireland and England they're few and far between.

My cousin put a steering wheel on his bike.

So it looked a little like this?

Since you've mentioned banana bikes, I'm considering trying this as my next project

[HossC]

They're kind of like the Raliegh Choppers. I don't know if they're big over the pond but in Ireland and England they're few and far between.

Sorry to interupt your thread with sad news, but did you see that Alan Oakley, the man who designed the Chopper, passed away last Friday. His wife confirmed the now-legendary story that her husband drew the design for the Chopper on an envelope as he travelled home from the USA, in 1967. The full story is here. It looks like Raleigh made a limited edition Mk 3 version in 2004, but moved the gear change and modified the seat - doesn't look nearly as much fun as the originals.

[CDoherty95]

To quote Bo quoting Uncle Jesse in Big Brothers Duke " patience reapes it's own rewards". This is certain the case for me at the moment. I've been combing the classifieds for a lawnmower since I bought this bike and kept turning down cheap lawnmower after cheap lawnmower. Now finally I've struck gold!! I found a petrol lawnmower being given away earlier today. I rang the number asking for more details and apparently all that is wrong with it is a broken handle. I'm going to Irish college at midday tomorrow (yay :( ) so I've arranged to pick up the lawnmower at 9:30. It's only a 20 minute cycle and it finally gives me the opportunity to test the Fall Guy bike and see how it handles carrying a lawnmower on it's rear rack.

I'll try and post a pic or two tomorrow, but I've still to pack and buy food and drinks ( I'm staying in the back end of nowhere, speaking a language I'm not studying, with no Dukes, HNet or bikes. Worst of all is there's no mp3s or iPods allowed so I'm going to go crazy from not having music)

[CDoherty95]

I got home the other day,and spent most of my time since sleeping and clearing scrap bikes from my garage and garden. I buy a couple of bikes every few weeks to strip and scrap. It's a lot cheaper than buying new or secondhand individual parts. However I hadn't gone to the scrap yard in a while so I had about 14 bikes to clear. Because of this I got €70 in exchange for the bikes, which I'm happy with.

Anyway unfortunately the lawnmower engine fell through, and now I'm in the middle of getting a mini rotary engine. It's €35 but the engine isn't working, so hopefully I can get it for €20.

[CDoherty95]

My friend Brian expressed interest in taking the pedals and cranks off this bike. It didn't bother me because they were going to be scrapped anyway. He took them off on Friday, which allowed me easier access to mounting a foot rest system. I also replaced the front steering, because it was badly bent. And I fitted an extra brake handle to the handlebars to mount the throttle cable to. I'm not going to buy the mini rotivator, because hopefully I can find a lawnmower when I go to the scrap yard soon.

Anyway here are some pics of the bike in it's current condition.

I haven't decided on a paint scheme yet, but I think I'll probably paint it gloss black.

[CDoherty95]

Finally, after daily trips to the classified ads I came across this.

It's an atco lawnmower from the 1940's. The man I got it from was throwing it out because the frame was badly rusted, so I got it for free. He also mentioned that he might be throwing out a few old bikes soon, and will let me know before he posts them online. I also saw a foldable wheelchair under a big pile of stuff in his garage, so I might ask if I could have that as well. I have another idea brewing, so watch this space...

Anyway I spent most of the afternoon taking it apart. I had to stop early because it started to rain, and I didn't have any space in my garage to work. Here's a few more pictures of the engine and disassembly process.

The handles from the lawnmower are ideal for chopper handlebars. I'll include that in the wheelchair idea.

The red part is part of the drivetrain assembly. I didn't get a chance to take it off so I'll start with that tomorrow.

[CDoherty95]

Here's a few more pics...

The original grass box. Unfortunately it was rusted through at the seams of the welds, so I'm just using it for holding small scrap pieces.

[CDoherty95]

I sent the final car load of scrap to the dump last weekend, so I've finally got space to work.

The man I got the lawnmower off is meant to ring me back next week about the bikes. He says he has to double check with his son, but I'm going to get at least four bikes and a wheelchair. The bikes are old, and are very popular in Dublin as frames for fixed gear bikes (fixies). They're bikes that can pedal backwards and forwards. If I play my cards right I could get up to €250 a frame, not to metion what I could get if I sold the wheels, gears and other parts. I'm planning on keeping the wheelchair, and modifying it slightly (that's all I'm going to say for now).

Anyway I've spent the last couple of days figuring out some way to mount the engine to the bike. I finally came up with a solution earlier today, but had to stop early because I burnt my hand after cutting something with the angle grinder and then picking it up (wasn't the best idea I ever had). Basically I'm going to use the original mounting plate for the engine from the lawnmower and bolt two metal bars under the rear rack. With this design the engine, mounting plate, metal bars all mount to the rear rack.

As you can see there is still a lot of excess metal, but I'm going to cut that off as soon as I have the engine mounted and drivetrain system set up.

I always cut the back off any bike I scrap, so I'm using the back end of a donor bike I had to mount the friction wheel. For the friction wheel I'm using an old single speed rear wheel. I only needed the hub, cog and axle so I cut everything else off. I'm going to mount another cog to the engine, and will have a chain running from one cog to the other.

This is a picture of the rear end and hub I'm going to use. I'm going to drill two sets of holes in the longer piece, and bolt it to the saddle and rear rack mounts at the seat post. I haven't decided if I'll bother using the shorter piece, because the bike frame is very strong and I've already broken a few drill bits on the frame.

[CDoherty95]

I've decided to scrap the friction drive idea, and instead weld the cogs on a rear wheel so the cogs become fixed. My friend Brian, who took the pedals off this bike for his own bike build, was at my house helping me work on a couple of small bike jobs when he mentioned that he had a welder.

Anyway I've cut back the mounting plate so it doesn't stick out, I've removed the little cog that was attached to the engine, I've bolted the engine,mounting plate,rear rack and supports together, fitted a new rear wheel, wired the front brake,put a new front tire on and mounted the throttle control.

And just to give y'all an idea of what the finished bike will look like.