i invested $571 into my first build. Not only was it fun but i learned so much more about 2 strokes sence i did my own porting and looking for different heads and pistons that will work with this engine and also learned how to tune the carb. jetting wise.
I highly recommend buying a dax lower end, i waited 4 months just for him to get them back in stock and luckily i bought one because they sold out in a week. anyway i took the bottom end apart to be nothing but very pleased to see the quality. Right off the bat you get hex cap bolts to hold the case together (allen head). I pulled the crank out and Duane had the manufacture use quality Japanese needle bearings and crank/clutch bearings, also the crank connecting rod lower hole has copper spacers. The crank very close to being true aswell.
Another thing iv noticed from buying duanes bottom end. The ebay kit motor i bought the clutch would wobble had cheesy needle bearings dark grey in color and no spacers on the lower con rod and only had 2 oil holes on the upper and lower con rod holes. Dax's has 3 oil holes on the upper and lower con rod hole. i purchased a new clutch shaft thinking the lathe f'd that one up but couldnt get it to spin straight. Dax's lower has almost no wobble, Everything is well lubed and are assembled in 2013.
I would look into a Hoca piston i payed $29 for and uses 2 piston rings that are 1mm thick and are chrome plated. The piston rings that our motors come with are 2 mm thick and not plated = 3x more wear on the cylinder plating the piston is from a chinese scooter but iv done my research and am trying it out. it has a reed port window in the piston so a reed valve must be used to stop the intake charge from blowing right back out of the carb.
Good luck!