I think there was a time when just about every one of these little motors were about the same, just the same chinese stuff that is rarely going to be high quality and they all seemed to be about the same. But the last few years some plants in China have made an effort to improve them. You will find that some engines have slightly altered pistons, or bigger needle bearings. They are certainly not all the same anymore. Also, some dealers will alter them, sometimes doing port work, or changing out bearings for better ones, or put different bolts or screws in them. If you notice, Dax calls his 69cc not 66cc, also, he balances and drills a hole in the crank for better oil flow to the needle bearing. He says on the website that they are built in the USA "from only the best Globally sourced parts. Engineered parts include 38mm 360 Degree Steel Full circle GP type Crank hand drilled and balanced , Con Rod with Center Oiling holes, Hardened 8.8 case bolts and cylinder studs, RB 6202Z Crank Bearings, HR 6202 Clutch bearing, 8.8 hardened steel clutch pin and bearing and more. Full Circle Balanced Crank is Design Copyright Protected ! Order either F50 or F80
Blocks below. Please allow 3-4 working days before Blocks are shipped since they are built, tested and then shipped. Thank you."
I'm not sure what you have to do to call something "made in the USA" but is this different than some of the 66cc ones on e-bay direct from China? Definitely! Does a balanced crank make a difference? Yes! Now, I'm not a mechanic or anything, I'm just speaking from my own experiences with getting my own motorized bicycle going. Others on this website have much more knowledge than I do about this.
