First of all, you do not HAVE to have a 26" bike to put a motor on one. I have two motorized bikes that are 20" frames with 20" wheels.
You should not tighten the nuts on the engine mounts before you put on the exhaust.
You should ALWAYS assemble everything loose, so that if you need to make adjustments, you won't have to loosen it all back up again.
you left out one very important thing....BLUE LOC-TITE on EVERY nut & bolt.
All in all I think it gives the newb an idea of what needs to be done, but they need to know that this video does not have to be followed exactly. They should be informed about some of the things that could be done differently.
like saying "this is a typical installation, but your results may vary" or something along those lines.
I also think that you should cover the wiring more (remove those plug together connectors, solder and heat shrink all wire connections for optimum performance). Explain the possibilities of having to flip the sprocket around, adjusting the clutch and throttle cables, and installing the slide in the carb. You would not belieive how many people put the slide in wrong when they assemble the carb., and then come on here saying that their throttle doesn't work, or that their engine is running at full throttle all the time.
People who use this video to actually build a motorized bike should also be informed that they may have to tweak a few things here and there to make everything work right. For safety sake, I also think you should have gone over the brake system on the bike, and make sure that the viwer knows that stock bike brakes will work, but they will not work the best.
There are a ton of things that should be looked, changed and modified when installing an engine on a bike, and you shouldn;t give the impression that just anyone can bolt an engine on a bike and take off riding it.
I'm not bashing your video because it is fairly decent. There are some things that people should know, who have little to no mechanical ability, or who have no researched this whole motored bike thing.
one otherimportant peice of information is the nuts, bolts and washers that come with these kits.
9 times out of 10, a newb will break or strip some of these nuts & bolts. They should be made aware of this and they shoudl also be made aware that it is a good idea to replace all nuts, bolts and washers with higher quality ones.
These are just my opinions, and overall I think you have a useful video there for new people who are trying to install an engine on a bike for the first time.
Altho, some parts if it can be misleading (like the time frame) and that everything will go together right on the first try.