So the Coleman minibike thing... Just picked up a B100 and a BT200X from our local Camping World. The service techs at CW said they did the initial assembly and setup. The 100 ran like crap when we got it. After an unsuccessful attempt at getting Coleman to reasonably accomodate some warranty work, I gave up and took it into a local small engine shop. The guy found multiple small things to adjust. Runs like a champ now. I decided to have him go over the 200 as well, where he found a few things to improve. The kids are loving them! I just need to get my Kawasaki 300 going too. Certainly not to smoke them punks on the trail...no, not at all. :)
In short, while mini bikes can be a freakin' blast, you might consider spending another $100 to get a pro to fine-tune it, if you didn't do the assembly yourself.
Not to disparage Coleman too much, but they couldn't find a local shop willing to do warranty work and after they found one about 2 hours away, they weren't willing to pay me for my time to get it there and back. They've ghosted me at this point...