Try #1. What material do you use for a motor mount? It's a no brainer - steel of course. So here's the first one. It's 3/16" plate steel. I used 1/4" for the CM400 conversion, and felt it was overkill. 1/4" doesn't seem like a big fraction, but when I was holding 1/4" steel, I had the sense I could bolt down a jet engine. (I know, If I were actually capable of calculating the thickness required I'd find I'm off by 1/16".) The next step was welding the steel mount to the NH80's aluminum crankcase. I did not know this, but it actually turns out to be somewhat difficult to weld steel to aluminum. Is it possible? Here's a site that lists about 10 completely different methods, that no one I talked to had ever heard of. My thanks, and apologies to Thomas who cut out the steel. If I had bothered to mention I wanted to connect the steel mount to aluminum he would have been able to better invest his time mixing Lychee martinis.Try #2. Steel won't work, leaving.. aluminum alloy? Sounds easy enough. Go to the store, buy some alloy plate. Well there are more grades of aluminum alloy than ways to fall off a bicycle riding on ice. Not to mention how thich does it need to be? This article suggests a thickness of 150% that of steel to give similar "stiffness". Is that thickness required for the same strength? How important a consideration is stiffness in this project? How does the particular alloy factor in? All reasonable, and still unanswered questions. I decided to go with 1.5 * the 1/4" steel, giving 3/8" aluminum plate. And the alloy? 6061-t6 as it was readily available. However when I arrived at the store only 1/4" was available. So I bought it. Holding the 1/4" aluminum was not at all the same experience as holding 1/4" steel. I didn't have the same confidence in strength, mainly because 1/4" plate alloy weighs next to nothing! Against my better judgement I decided to use it. The next question was how to cut the plate. A bit of research turned up using a water jet. Apparently a plasma torch doesn't work well for the alloy. I found a local shop that could do the job. When I got the plate back, however, the cut was slightly off, enough that it wouldn't hold the motor in the right position.
Try #3. I was relieved. I went back to the same store and found they had some 3/8" 6061-t6 plate this time. I took it back to the water jet shop, and the final mount was created.
The mount required two pieces. The additional smaller rectangular plate was needed to keep the motor level, but also hopefully to lend some strength to the faceplate. Although it's not shown here, all three pieces (crankcase, side plate, and bottom plate) are welded together.
The side view shows the finished mount. I would have liked to extend the piece to the back of the crankcase, but the transmission is there.
Here you can see something else I would have done differently. The plate is cut very close to the edge of the motor, leaving the top bolt holes very close to the edge of the plate. I should have left a little more overhang than I did.The last step was welding all of it together. I went to 3 places before the last place recommended Miro who was able to help out.
One place along the way said they couldn't do it because of "the exact tolerances" required. ROFL.
More on the original plan for the transmission...
The original plan was to weld a sprocket to the rear wheel, bypassing the scooter's real transmission/gearbox, and I actually bought the pieces to do this. It would have involved cutting a piece from the gokart shaft, welding it the exact centre of the rear wheel, and then using the gokart hub and 2-piece sprocket. Welding it to the exact centre of the wheel is where I think there might have been a problem.
If anyone is looking for a really cheap gokart axle, aluminum hub, and 2 part sprocket, let me know.