I am happy with my purchase. I am a first time mo. bicycle builder. I bought the 48cc Grubee Skyhawk black painted engine and kit for about $150 shipped.
I clicked on an ad at this or another mo. bic. site.
I got everything promised, with lots of spare bolts, gaskets, spark plug, etc, and a long enough chain. There were photocopied instructions in English, surprisingly legible, though it did have some funny malapropisms, such as Tickle Button for primer bulb/button, and a description of the engine as a Roundhead Wingding. hahhaha.
I didn't like the chain. It is a 415 style, wide with loose rollers floating on the pins. Maybe this is part of the design, but to me it looks like poor manufacturing.
The muffler didn't fit due to bic. frame construction. This is fair, since its a therefore a "custom" build. I damaged the muffler and didn't expect a replacement without paying. They only offer the same black or silver "poo poo" pipe. They do not offer any with more flexible pipe or different configurations.
The clutch lever was deformed and poorly assembled. I had to file out the arm's locating ring and press fit it onto the clutch activation rod. (the thing that pushes on the shaft inside the drive gear). I made it work, so I didn't ask for or order another, but I was miffed at the quality control from the motor factory, not bikeberry, since I didn't give them a chance to offer a replacement, but fixed it myself.
I mounted an alternate muffler and test rode the bike today. I am pleased. The price seems fair. The product seems good. The email/chat service person was polite.
I gave them a 4 because of the lack of alternate mufflers. Otherwise I'm fine with them. I feel they did not rip me off, because they might not have known the clutch arm part was bad.