I started building in April this year and havn't stopped since. Lotsa head and heartache. Also I must say I'm 51 yrs old and havn't had so much fun on a bike since I was 8 or 9 yrs old. Initially thought about building and selling... Cant make money on'em due to the time it takes to make em reliable. I - like everyone hope for an engine that would run great out of the box. Not so. Here's my newbie observations thus far: Out of 5 kits only the one from BB ran and ran well on the first run. One vendor In particular (out of three I've patronized)is a BAD place to buy. Noticeably bad cylinder cast, tiny headbolts and what appears to be a fudged with I.D. plate cover. It looks like a 48 not the 66 I ordered. This guy does not respond to the customer after the sale Period. He's in So.Cal. I'm on the other side of the world as far as he is concerned. So the non communication (No Ph or email resp) from him tells me he had some used or returned parts to build a kit and was waiting for a sucker like me to come along. That's ok Fool me once! $200 lesson for me. I'm 179 ft above sea level here in Bangor Maine. I'm not sure why but I can't get a CNS carb to dial in well at all. Very poor low end perf. No power anywhere in the throttle, Doggy as ****. The NT carb works excellent with a little bit of 4 stroking. NT is best in this neck of the woods.. I like it that there are lots of inteligent people that think like I do about these simple little motors. Looking for ways to make them stronger and more reliable. ---And this forum is a godsend.