So I recently decided to sell my scooter and build a new bike. All the previous bikes I built were with cheap 2 stroke kits. Mixing gas sucks, as does pedaling up to speed to start the engine. So I got a 4 stroke kit. Grabbed a cheap Walmart beach cruiser to mount it on, and a bunch of small extras(mirrors, lights, rack and trunk, etc). The mounting plate came broken, of course. And the seller was no help. I wasn't about to pay $50 that I don't really have for another one, so one trip to Home Depot and $4 in nuts and bolts later, and that issue was solved. Got the engine mounted, then everything else. Put in some 10w30, pushed it to the gas station, gassed up. Engine started in 2 pulls. Walked it home. Started up and ran the engine a few times, 10-15 minutes each time. With the bike up on the stand, hitting the throttle gets that back wheel moving like crazy. But the problem is, if I sit on the bike, no amount of throttle can get the bike moving, unless I am facing downhill a bit, or a push off with my feet(I have no crank/pedals. And if I do move, it's gotta be like 5 mph. The engine will rev up to what seems like about all the RPMs in the world, but it just won't go more than that 5 mph. And if the bike if facing a slight incline(not even a hill, just the tiniest of inclines), you can forget it. It will just sit there, and I'll hit the throttle for a few seconds before I'm afraid of destroying the engine or something. Anyone have any advice here? What would the most likely things to check be? This is my first 4 stroke, so I'm used to the 2 strokes, where either the engine runs and you go, or it doesn't and you don't. The 4 stroke kit WAS just the cheapest one I could afford from Amazon, so it's entirely possible that I just got a piece of junk. Unfortunately though, it doesn't look like the seller is going to be of any help with returns or replacements or anything, so I'm stuck with what I have.