Myself I replaced the rear mounting studs with grade 5 bolts that I just cut the heads off of and make studs of them, that is a good idea in my opinion because I had issues with the rear studs breaking on me until I made that change, somewhere like a good hardware store or a place like Fasten-All will have what you need, those rear studs are about 75-80mm's long I just bought some 6mm X 100mm bolts and cut them to length, I also replace the machine screw/bolts that hold the clutch cover and sprocket cover on with grade 5 allen-socket head bolts (optional), and I use allen-socket head bolts for the front engine mount instead of the studs that came in the engines I have, by doing this all you need to have as far as tools is a 5mm allen wrench, a 10mm open end boxed end wrench, and a #2 philips screw driver, on the carb studs pick you up some good quality nylon inserted 6mm lock nuts and I highly suggest that you get you a piece of 1/32" fuel safe gasket material and make you another gasket to go between the intake and the cylinder and apply some gasket sealer to both sides of gasket, I prefer the permatex aviation gasket sealer that comes in a can that has a stem with a brush on it attached to the inside of the lid, it is much better than silicone in my opinion, it actually glues the gasket but stays flexable and seals under heat and pressure much better than silicone, be sure and check the head stud nuts for tightness and use double nuts on the exhaust studs when you mount your muffler also remember to use the blue loctite on every nut and bolt, these little rascals will vibrate the nuts right off in many cases if you dont, I know this all sounds like a lot of info. here but I'm just telling you what I've learned on my engines through trial and error.......so bare with me here and just maybe I can save you some headaches and help you to get off and running without to many mechanical issues.
Go to a parts house or a motorcycle shop and get a NGK B5HS, B6HS or B7HS Spark Plug any of these will work fine, and also go ahead and spend 3-4 bucks and get a NGK spark plug boot I use this one NGK part# LB05EZ this will save you a headache believe me, the ones that normally come with the motors dont last long at all just a few miles in my case on 2 motors before they came apart on me.
Now another very important thing is....when you mount the engine at the rear which will be on the upright tubing that the seat post is in make sure that the rear engine spacer that goes up against the tube is flush and flat against the upright tube no gap at bottom or at top if not it will put a bind on your rear mounting studs when you tighten them and most likely the engine will become loose and/or break the studs, this is very important so dont overlook this one. now if you have a drill and a small drill bit set you will want to perfom this little very important tweak to the chain tensioner once you get it in place and you know the tensioner is where it needs to be with the chain roller in it's lowest position so it can be raised to take up the slack as the chain stretches and the sprockets wear in, the pic below shows what I'm suggesting you do to your tensioner where it clamps around the frame, now keep in mind your tensioner will not look like the one in the pic because this is one I rigged up for the latest bike I put together, but the lower part will be very simular and you will see what you will need to do, this will keep the tensioner from rotating inward and getting into your spokes on the wheel, imagine what this would be like @ about 30mph.....! not good.....! all you will need is one small self tapping sheet metal screw and you will drill a small whole through the tension bracket and the bike frame just large enough for the screw to thread into, this will eliminate the chance for the tensioner to rotate inward and make a big mess of things and possibly get you hurt in the proccess.
I know this is a lot of jabbering but if you will follow these directions when you go together with your bike it will sure give you a better and much more dependable set up.
Good luck and I wish you lots of fun safe miles in the future on your bike.
Shan
I've heard that the China imported bolts are crap so I was thinking about doing that as well, unless the bolts aren't compatible with the engine