you will need the following:
1. Blue loc-tite..use it on every nut & bolt that you can.
2. replace all of the china lock nuts, bolts and washers with better grade american lock nuts, bolts and washers
3. a soldering iron, solder and heat shrink to do the wiring right.
4. plastic wire ties to keep your wiring nice & neat (hide the wiring as best as you can for a clean look).
5. a chain breaker to shorten the drive chain (or a grinder, a hammer and a punch)
6. teflon tape to go on the threads for the fuel tank petcock
7. Lots of patience. do not get in a hurry, take your time and do it right. you may have to modify or even make a few parts depending on what kind of frame you're using. do not expect it to be a "bolt on and go" kind of thing....it usually never goes that easily.
sometimes they will start right up on the first try, other times, you may find yourself having to mess with the carb a little bit. sometimes the float can get stuck in the float bowl sideways during shipping, which will do one of 2 things. It can either make the carb flood over or it won't allow any fuel to flow into the carb.
do your wiring right and do not use the kit supplied push together connectors. they are junk and they will fail after awhile.
you should replace the spark plug that comes with the engine kit with an ngk B6HS plug. Get rid of the spark plug wire and replace it with an automotive spark plug wire with a rubber boot. this will also allow you to get a longer spark plug wire so you can hide the cdi box somewhere. 95% of the time, you see the cdi box mounted in plain sight, right on the lower frame tube. This will have your wiring that goes to the cdi box strung all over the frame, and in my opinion, that makes the bike look like it was just thrown together quickly.
you have to be able to troubleshoot simple issues without freaking out and thinking that it's junk.
remember, you're dealing with an engine that is a 50+ year old Russian design, made in china from recycled pop cans and coat hangers, assembled by a guy that probably makes $3.00 a day.
they assemble these kits as cheap as possible, so they throw in some cheap nuts, bolts and washers, a cheap spark plug and a VERY cheap spark plug wire.
most of all have patience and take your time....don't expect to throw it together in a couple of hours.
if you do throw it together in a couple of hours, be prepared for something to fail in a short amount of time.
This is just my opinion, but I don't know how many times i have read about people saying that these kits are junk. then find out that they assembled them as quick as possible without using better nuts, bolts, washers, loc-tite, or soldered wire connections covered with heat shrink and no knowledge of how to correctly build one of these bikes.
there are so many things that can and will go wrong, you need to know how to work through those things. you need to know what correct chain alignment looks like, correct chain tension, how to assemble the carb slide correctly, how to do the wiring correctly, how to mount the engine correctly, how to get it to run when it won't...the list goes on and on.
I know, people have to learn somewhere, but without the correct advice BEFORE they even start building, they rush into it and expect it to be a simple thing to build. I mean it is relatively simple, but it can be built wrong very easily.
again, just my opinion.