that was what i was thinking... i actually found a seller on ebay that has spring loaded idlers with actual sprockets rather than the vinyl wheels... like $56 or so and you get a set of 2... now the truck is finding a good frame... seems to be a bit of a pain in the ass finding a frame that is full suspension AND can accommodate the motor...
almost had one yesterday but got outbid at the last second lol
I am completely lost with your situation...
You have a soft-tail bike or not?
You have a 2-stroke and want to run it direct drive with a complicated tensioner system?
The very best way to motorize a soft-tail is with a jackshaft tied to the pedal system.
The pedal system already accounts for the swing arm movement and the engine can use the pedal gears with a $200 SBP jackshaft.
The trick is the rear shock not be in the center cavity of the bike like above, but most soft-tail bikes you see with a rear shock our mountain bikes with a center cavity too small for a gas engine like this bike in the build bay now.
In that case you go electric shifter.
Then fill the small center cavity with lithium ion batteries.
Pricey, but uber cool ;-}