In late-January, I spotted something on Marketplace I just had to have... it was an unfinished project and I was essentially buying an idea... a vision. Someone had started to put a motor in bicycle frame and, to me, it looked awesome. It wasn't just any bicycle, it was an early-2000s Schwinn Stingray that was the result of a collaboration between Schwinn and Orange County Choppers (O.C.C.). It needed work (I didn't realize how much), but I knew that going in. I was told the 50cc motor ran (nothing was hooked up to prove it) and, given I had experience with my Honda Z50, I took a chance.
Here are 2 photos from the listing (not taken by me). Seriously, these sold it. I'm not sure what's wrong with me, but I saw these and had to buy the thing. :)
It certainly wasn't advertised as running but the photos are a bit deceptive in terms of how close it was to running. When you look closer, the motor was only tacked in place and the seat was propped up. A chain roller, throttle, exhaust, and carb had been added and the chain was on, so the potential was clear. However, the list of what was missing was long: brake cable was too short, no battery, no battery mount, no tank mounts, no proper wiring, no solid engine mounts, no exhaust mount, no solenoid mount, no coil mount, no seat mount solution, incorrect sprocket cover, no kickstand (the center stand sucked), and no footpegs. It was a bicycle after all. The fact the motor was electric start made the list of requirements more complex than a kick-only motor. On top of that, the bike was spray painted flat black, which looked decent from a distance, but someone just painted right over all the decals. The chrome on the forks and exhaust was a little bit rusted and pitted too. The handlebars had blemishes too and the crossbar was slightly bent. Some Schwinn/OCC Stingray bicycles actually came with a motor but it was a much different configuration. Making THIS motor work in THIS bicycle would take a lot of creativity and fabrication.
Before investing any time in cosmetics and adding all the things that were missing, I needed to ensure the motor actually ran. I hooked up just enough to make it run aaaaaaaaaaand it wouldn't start. The starter was trying and it seemed to have air, fuel, and spark. But it wouldn't run.
I tried swapping carbs and coil with no luck but what kept bothering me was the spark plug hole. Something seemed wrong and I couldn't quite find a plug that seemed to fit right. I came to the conclusion someone likely modified it. I bought a whole new head, swapped it out, adjusted the valves, and it fired right up.
Once I knew the motor ran, it was time to build the bike. An early mockup utilized my "Toasted Monkey" tank. In my opinion, it looked SOOOOOO badass like this, but the tank was truly toasted (inside and out) and would need extensive repair and petcock relocation to work. I thought about buying a new tank and trying to make it look like my toasted tank but that just seemed way too complex, costly, and ambitious. I was trying not to go overboard (ha ha). ...and, yes, I am well-aware my workspace is a total mess.
Before I tore it all down to start modifying, I took lots of photos of how things like the brakes fit together. There was black spray paint over everything. There was even overspray on the rims.
First step in actual modification/fabrication was a top motor mount. I drilled a hole for some tube. I was going to connect the 2 holes with some flat stock.
The seat post used to go through the frame where the motor would be. I wanted to plug the holes, so I cut out some blanks to weld in using low-tech garage-built methods.
I cut off the center stand and prepped the bottom of the seatpost hole for welding.
Here's a good look at the bike frame before most of my modifications. Also note the flame stickers on the front forks. Originally this thing was covered in flame stickers.
Kickstand mockup:
Tacking top motor mount,
I decided I needed 2 mounts along the backbone to form a triangle that would not allow the motor to move. At this point, I welded up the seat post hole in the bottom tube of the frame. I also ground down the fender mount to make room for a battery box
I made the battery box out of some steel angle and flat stock. More elements would be added later.
I made footpeg mounts by welding a nut to the back of the circles I had cut out with my hole saw. Then I welded that in where the pedals used to mount.
The patient on the operating table:
I decided that I didn't like how the tubes for my top engine mounts stuck out and needed to change the design. I cut them back and chopped up the mounts I made. It was re-work, but I was really happy I did this.
I decided to not use the stock seat and go with an old-school banana seat. I wanted to incorporate some elements of vintage Stingray bicycles into the build.
Using my low-tech method to make a ring out of steel. This was to reduce the size of the seat post opening so I could weld in a post to fit the banana seat.
Coil mount cut and gas tank mounts in progress. There's clearly no CNC machine in sight.
The chain roller that was included was functional but so ugly. I decided to do something different.
I got a different (slightly bigger) tank and here's the mock-up with the banana seat and sissy bar.
With the front-end apart, I made a headlight mount and welded it on. Stock, the bicycle would have just had a little reflector. Note the spring snow. Fun.
I added a retro-looking LED headlight and tailight.
The taillight fit great under the seat and I think it strongly resembles the red reflectors used on Stingray bicycles. You can see my welded-in seat post here too. No adjustments are possible - it is what it is.
Since I didn't want to have to pull the motor to change the oil, I had to notch the frame. I never notched a tube before but I just went slow with my angle grinder and made some magic happen.
I had to do the same to the backbone for the petcock to fit.
Next up was an ignition switch mount. I made it out of 2 pieces of steel. Cutting the keyed notches (so the switch can't spin) was tricky but a jigsaw helped do the trick.
I plug welded the two pieces together and then ran a bead around the edge before grinding it down.
Battery box mount. I wish I mounted these tabs slightly higher (flush with the backbone) as I had to use some spacers later during assembly.
Tank mounts, coil mount, and chain roller mount are all welded on too.
You can see the battery box and ignition holder that I welded to it.
A view looking down at the battery box, now with solenoid holder welded to it too. The exhaust mount is visible in this photo too. It's a steel tube running through the frame, similar to how I made the upper motor mounts.
Everything's mocked up. At this point, it was ready for tear down and paint. I just had to notch the fender (the blue tape was there to represent the chain so I knew where to cut). It was pretty much all the same problem solving and work required of a bigger chopper, just in mini-form. The only thing I didn't bother doing was adding a brake light switch - I'm not riding this thing in traffic and the taillight was intended just as a running light.
If you look at the battery box, you can see the top clamp I added there too.
Prep and paint photos are up next!
