On my Scooterguy center-mounted engine, I use 11t T8F sprocket on the transmission to a 72t chainring. With an 8 speed cassette, it allows me a granny gear of 46.36:1 and final drive of 15:1. If I had used bicycle sprockets, my first gear would've been 28.33 (my present 3rd gear) and an unusable 9.2:1 final drive.I just googled T8F, and it seems that its related to scooters and mini-bikes mostly. Not to be rude, but this is not a scooter/mini-bike forum. It is a forum for motorized bicycles. Most of the information that is exchanged here is related to installing engines to pedal bicycles.
Without ordering custom sprockets, you'd have to switch to #25 chain and sprockets. They have the 3-hole bolt pattern too. ScooterParts4Less website has 78t sprockets for $12. Davesmotors.com has 98t sprockets for $24. For strength and simplicity, a custom T8F might be the right choice. I like the fact that they are smaller in diameter than regular bicycle chainrings. They also allow for awesome gearing. My first gear is 46.36:1, which is great for very steep hills. Good luck.Please help if you can, I have a tri stud mounting pattern 33mm (1.3 inches) centre to centre. I cant find anything over 74 teeth.
Ideally I would want 80-90 teeth. Searched for hours :-(