I would go and order from revolutioncycles.us. I ordered a powerkingshop HT 80cc kit on ebay and so far i am a very dissapointed. Most of the parts are extremely cheap and the engine has HOLES in it. The upper assembly has about 4 holes in it. I patched it with quiksteel and it seems to be holding, but that is ridiculous. Also, my muffler broke already and had to repair it with quiksteel. (The baffle shot out while i was riding and i almost s**t myself.) The third and final problem was that my throttle/killswitch is garbage and i had to heavily modify it just so it would work. but wait, theres more, the throttle cable was too short and all of the gaskets have rotted out and or broken. Keep in mind that i have had this engine for about two weeks and i am very mechanically inclined. Rebuilt two VW bugs and worked at a bike shop for a year.
All these problems really p***ed me off and i wanted to return the engine but am too cheap to ship it back. DO NOT order from powerkingshop or anybody selling engines on ebay unless they have reviews, most of the parts are cheap and you will be waiting for at least 3 weeks before you get your engine. Revolutioncycles.us has good engines and very good components i have looked at all their kits and they have real quality components. Don't waste your money, spend a little extra and get something that will last.