Custom motor mounts welded to frame?

Springfieldscooter

Springfieldscooter

Member
Are custom motor mounts welded to frame a good idea?

It seems to me that a lot of mounting troubles could be resolved, by fabricating motor mounts out of .0125" x 3/4" tubing, and .0125" x 1" plate. And then welding the mount to the bicycle frame, exactly where you want it.

Steel mounts for steel framed bicycles, and aluminum mounts for aluminum framed bikes.

Does anyone believe that even if fabricated properly, that this is a bad idea?
 
Skyhawk frames have a pedestal mount for mounting 2 stroke China Girls and they crack at the weld where it's mounted. Aluminum frame. Chinese made.
 
Thats because they're poorly welded. Several members here have welded mounts for several different types of engines. With the morini engines, you almost have to weld the motor mounts on, and it's certainly better if you do. Same with the 212 Predators. And if you really think about it, on motorcycles they aren't simply welded on, but actually structurally part of the frame as well. So no, it's not a bad idea in fact it's a very good one. Personally I think the reason the skyhawk frames fail is because the Chinese worker who make the frames are not very well trained in the techniques needed to weld aluminum. Its a bit different than welding steel, and then you need to properly heat treat the material you've welded as well and I don't think they do that either. Even some bikes sold at Walmart are not properly welded sometimes. In short, welding motor mounts on is a great idea if you do it right.
 
My first motorized bicycle relied on the kit mounting method. After that I've fabricated and welded all my mounts which have proven far superior to the clamp-on version. I don't tell eveyone to use this method because I understand that everyone doesn't have the required equipment or welding skills, but if you do, welded mounts will serve you well.

If you don't have the necessary things to do it yourself but know, and trust, someone who does, welded mounts are a good way to go.

A few words of caution: You must have your engine aligned in the frame correctly before welding the mounts. An engine that isn't sitting straight and true will throw your chain/sprocket alignment off which will open a new can of worms for you. Check then re-check, then check again before striking that arc.

Tom
 
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Thanks for the info!

Ive got some 3/4" x .0125 tubing and 1" x .0125 plate ordered.

Ive got a tubing notcher, and a Miller mig.

I think I will use new chain looped around both spockets, and "eyeball" the alignment ...

Then I plan on tack welding the motor mounts, and test drive prior to finishing the welding of the mounts...
 
Show us the results, Springfield. Take some photos and share your work with us.

Good luck.

Tom
 
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