Not trying to stir any pots here but I would also have to agree there 100%...
Depending on the type of bike, some people need to slightly file their dropouts, and others have quite a generous dropout axle spacing that does require you to tighten the nuts maybe more than you would normally. I know yours is a front motor..
Personally, my bike has ridiculous dropouts - before running the wheel I made 2 small plates of metal and used that as a 'torque plate' that bolted to the bike frame:
http://goldenmotor.com/SMF/index.php?topic=2278.0Even the ones you buy commercially need some form of modification as the dimension and dropout angles vary so greatly.
Valy - a member of this forum made some fantastic custom ones that he has mentioned he can sell. See this post:
http://goldenmotor.com/SMF/index.php?topic=2513.0Even though you may think its too late, it's not... Should you wish to replace your internal controller and cable will probably cost you around $50, and if you want to go external you have some options from around $50 to +$100 for an GM External or Infineon controller.
That said you can still get some love out of your bike
Don't give up now, imagine if you had an accident in your car. The motor was fine, but the computer that told everything your car to do was broken. You wouldn't just sell the car because of the broken computer
Front wheel kits are also notorious for aluminum front dropouts, if you have alloy forks then 100% put something there to stop this or buy a set of steel forks. GM or not, it would have failed with any motor with power.
I only have a torque plate on the rear, my forks are steel and I tighten my nuts with a tyre lever - and hence the name it has excellent leverage, maybe a bit too much. Anyway it does not budge 1 bit, I also check my nut tightness along with my tire pressure before every ride just like I check suspension, brakes and air pressure before a long drive in the car... Safety first ~~!
Peace out MM