Hi All, names Dave, New to forum, not new too 2 cycle tuning. I own operate R&D MRD Racing performance engines. mostly build marine 25-31cc high performance model engines, Really enjoying the bike motor project thus far. so 29" beacher, with 44tooth and nt carb on the 66cc motor. could not leave motor alone, first thing out of box pull it down, lower intake floor, raise exhaust timming, mod transfers and eyebrow them forward. NT carb way to lean out of box, made jets on lathe, and fitted a kx60 chamber, and put stock muffler on rear, pretty quit. best pass on gps with me @ 230lbs. flat 40.6mph @ 9800 rpm. just ordered an RT carb from Dax, may put a 39tooth sprocket runs out of gear, oh and put a cheap straight plug head on for 40.00... really helped with head temps. about 100 deg. cooler at plug.