Nice picture, shows a lot of detail. I notice your exhaust is not clamped to your bike. I would highly recommend doing it as the vibrations will break it off the engine. Don't bother using the kit bracket, it lasts about a day then falls apart. If you don't have any scrap steel laying around go to a hardware or Lowes or Home Depot. Most of these places have racks with assorted steel standing up in 3, 4 and 5 foot lengths. Get a bar about 1/16 inch thick or less, 1/2 to 1 inch wide bar is what you need. Or go to a welding or fabrication shop and ask to look at their "drops", sometimes they will let you have scraps for free. A junk yard is also a good place to find scrap steel. I made mine out of scrap that I had laying around. I got it hot then wrapped it around a pipe to shape it.
You'll notice I used a peace of inner tube on the bike for the exhaust clamp. But removed the rubber on the engine clamps. I also purchased a 5/16 clamp for the front engine clamp to replace the thin one in the kit. If you also notice my intake manifold is extremely short. The carburetor is almost touching the engine it's so short. I think this will work on your build. Your throttle cable should be routed against the bike frame and not taunt as you have it. Route it against the bike frame then check by turning the handle bar to the left and right, if the throttle moves it's too tight. Fasten with zip ties. It you keep it like that, turning your handle bar will race the engine. You might even brake the cable. Get a dual brake lever and put both brake cables on that one lever on the right side of the handle bar. Put the clutch lever on the left side of the handle bar.
The 415 chain will keep stretching and cause you a lot of aggravation. I recommend getting a 41 chain. They come in 10ft lengths so you can make at least 2 for less than $9.
Buy 4 master links they are very cheap. Two in a pack for 49 cents can't beat the price anywhere.
If your magneto has a white wire I would recommend taping it so it can't short or cutting it off next to the magneto, it causes more problems than anything else.
Buy a center kickstand, here's what I bought. Sometimes Walmart sells them for $15. Check there first, your local store may have them.
When it's in the upright position make sure it's not close to the ground. If it is mod it by cutting about 1/4 inch off the little stop tab. Then check again.
Take your hubs apart and grease the bearings. Careful some wheel bearings are loose and will get away from you. I bought this grease for my bike needs.
Use the P20 code and get another 20% off.
Well this post will get you going. If you need any further help let me know k.