Steve, i remember you from previous posts. you were so impatient to install the engine so you could ride the bike this summer. you just wanted to assemble the bike, then work out the bugs.
now here you are.
good news first, then the bad news. Steve, it looks like a very clean installation. using the bike's gear is a step in the right direction.
bad news next. engine mount needs more support. it seems like the engine is floating upon that aftermarket rack. maybe two support legs to the rear dropout area would help, ala STATON friction drive supports.
the REAL bad news is that your final gear ratio is WAY OFF. your 13t drive sprocket and 36t driven sprocket results in 2.76:1 gearing.
let's compare your rpm output with a 8500rpm MITSUBISHI 2.2hp engine(mine). my final gear is 16.67:1. for the sake of comparison, i will calculate everything on a 26" bike.
at 10mph, your engine rpm is 350rpm; mine is at 2100rpm.
at 20mph, your engine rpm is 700rpm; mine is at 4200rpm.
at 30mph, your engine rpm is 1050rpm;mine is at 6300rpm.
at 40mph, your engine rpm is 1400rpm;mine is at 8200rpm.
at 41.35mph,ur engine rpm is 1450rpm;mine is at max hp range at 8500rpm.
at 243mph,your engine rpm is at max hp range at 8500rpm.
your clutch will burn out before you reach 10mph.
comparing my 16.67 gearing with a happy time engine, it'd be like 10t engine sprocket and 41t rear sprocket.
with your 13t sprocket and 36t rear sprocket, it'd be like 10t engine sprocket and a SIX-TOOTH sprocket in the rear!
Changing engine sprocket to 6-tooth still would not correct your error. shooting for 14.76:1 final gear(happy-time with 36t rear sprocket), you need to install a jackshaft to reduce gearing an ADDITIONAL 5.35:1, preferably one that links the 36t driven sprocket with a 7t jackshaft sprocket.
either that, or keep your 13t engine sprocket and install a 192-tooth rear sprocket.
Myron