Let the building commence!

Looking good.
Is your carb siting level ?

I can talk here about the issues that everyone faces at the beginning of their build. Your frame's seat post is nearly Perpendicular so the closer you can get to flush there will help you later, Front mounts are sort of centerind pins. to be finessed in while checking petal travel, muffler proximity and center of gravity.
I replaced my orig studs with hardened Bolts that ensure strength and minimum protrusion.
took my rear motor adapting block and shoved it tight to the seat post portion.
infront I noticed that an angle could be ground in to the aluminum spacer that matches the angle to truly flush it all in tight. I got ahold of some "lock-tight" and smotherd the threads to ensure that this portion of the build was set to forget.
While the engine gear remains stationary You may fiddle with the rear Sprocket as often as you need.
earlier today 8 wisemen handed over tips on the sprockets jnstallation each one admit to taking longer than one evening to assemble this Engine Kit most of the red knuckles come while inserting the half moons behind the spokes and getting the nine bolts to penetrate the gasket material.
I came up with a Bosch mini power ddriver and zipped them in and out wuickly clearly an improvement on my knuckles and serenity. I had not noticed the power driver mentioned concerning this portion of the one by one through bolt aspect . I haven't heard of a newbie getting it in right
on the first try. so I put this note in for ya, get a power driver to penetrate the three in one assembly, then it is automatically flush in the inner circle

There is no chain clearance ? I sent this pic of my sprocket, I even left off the outer gasket to
ensure my coaster brake arm seats correctly in its notch on the axle. compromising an 1/8 inch clearance towards my spokes. If you've installed the rear wheel loosely, it travels enough out of kilter to apear that the chain will hit the tire. Your tension device is supposed to be set just right to enable a feed into the rear sprocket and align it avoiding thrown chains

I went to spooky tooh cycles and pulled a pictue of the wheel they sell with the sprocket on it see

make your wheel look like the one at spooky tooth he is the s@@it

actually, some bikes need the "dish" of the sprocket opposite of what any instructions might say. you'll know after everything is installed and you look at the alignment of your chain whether or not you gotta flip it.

that's a nice exhaust pipe. Where'd you pick that bad boy up?

That's a sweet exhaust pipe. Did you fashion it yourself?