Coolster Issues

[WarZ]

I picked up a coolster twin pack. I'm both pleasantly surprised and somewhat annoyed by them at the same time, lol.

For the money, they make a fun little zoom around fun atv. And you can do some surprisingly decent riding on them. Definitely on the stiff side, both steering and suspension, but I knew that going in.

But both machines have issues right off the bat.

Machine # 1 --> Something is not right with it.
- Maybe frame, maybe not.
- The machine drives extremely rough / almost juddery. A really strong vibration occurs. My guess is chain is too tight ? Transmission ? My 2nd machine runs nice and smooth (mostly) compared to this one.
- For the life of me I could not get the seat to attach normally. I spent hours on it, checking every little bolt and screw in the whole setup, trying to get it to seat normally. My cross bar the front seat hook slips under was bent down a bit. But in the end, the only way to attach the seat hook in back is to put a huge downward pressure on the seat and tap the hook forward onto the attachment spot with a hammer. On the 2nd machine, both seats go on just fine and smooth, so its not the seat.

Machine # 2 --> Seems to have broken after the first test ride.
- Took it on a nice little 5-7 mile ride on the trails - nothing insane. When I went to load it, I noticed it was hard to start. Had to give it a touch of throttle to get it running. Next day, went to start it and I cant get it to fully start. It is trying to. But it seems like its about to start then there is a sharp clunk sound coming from that lower right side (clutch ?), and it stops it cold. Not sure where to start guessing on that.

I hate the idea of having to strip it down after just one ride :(

Any guesses on where I should start ?

TY