found this site. It might be useful for us

[sojudave]

This site sells engines and parts for mainly small scooters, E-scooters, pocketbikes and so on. I checked out the electric motors and they are fairly inexpensive....but of course, we often get what we pay for. There's a lot of parts and I'm certain that some of us could make use of what they sell. I've not bought anything from them, so I can't vouche for the reliability of the site or company. Chinese scooter parts, wholesale scooter parts, ATV parts, dirt bike parts, 2 and 4-stroke engine parts, motorcycle parts,

[MyPC8MyBrain]

Hmmm... this has potential:
Chamber

25 bucks and 8 shipping... cheap enough to chop up and splice into the bike.