The Problem with GasBike.net or King Motors, I don't think is just the kits you get it. The big problem with GasBike.net is getting them to ship you your order in a timely fashion, and then getting all your parts for your Order. On Sep 1, 2018 I ordered a GT7 Pro Racing kit with some other parts. I got everything just no Piston or Cylinder. Now I don't know of any motor no matter who it is from if you don't get the Piston or Cylinder you have a paper weight.
That would be like trying to build a computer without a processor, or Ram!
I am sure they all have their bad points but I can say that GasBike.net or King Motor is the worst. I Emailed them asking about my order. That came today it is just a paper weight since I have no cylinder or Piston!
For us it is a crap shoot finding a company that will deal straight with us!