Originally Posted by Nougat
One, a properly installed and running HT engine kit will last a long time, well over a thousand miles.
For commuting, it depends on how sturdy your hind end is, and how long and treacherous your commute is. Bicycles, even with suspension forks, aren't sprung like scooters.
Well i am very tough
I would pedal the bike if i had no other option
So if i take good care of the engine whats a reasonable life to expect on the piston.
Just the piston and cylinder walls.