Like Phatman Motors, my 80cc (mallory power cell [gives our cdi's a stronger spark, speed increases 3-5 mphs fits bikes perfectly], msd 8.5 plug wire, bosch platinum size 4302 [it has two ground electrodes=more sparks=more power], 27 sprocket [main modification increase speeds up 10 mph from kings sales and services], and an uncorked original mufffler (increase power about 5 mph alone)...I've gone 48.5 mph drafting a delivery truck and I was gaining on it pretty qucikly had to slow down. I also cruise in the 40's about 95% to full throttle. The kind of bike you use also matters because of weight. Mine is like Lance Armstrongs bike but the cheap end a trek 370 with thin tires. Man guys, my rides are an adrenaline rush now because I ride my MB to work and back. One way is about 33 miles so about 66 miles total trip. Peaple just look at me like I'm crazy or amazed at the speed I'm going. I stress wearing helmets going at these speed even wearing a motorcycle helmet. And I give the mopeders a run for their money. My next add on is an engine sprocket with 11t. This will push me in the 50's and probably cruise at 45. I will finally catch this guy with a sooped up moped going 50 mph +. One last thing, I use premium unleaded gas with octane boost and 16:1 to 24:1 oil/gas mixture. If you got 16:1 [more oil in gas] lean out your idler screw, turn it clockwise for leaner gas and versa counter clockwise if you use 24:1+ [less oil in gas]. Guys/gals try these tinkering ideas and post your outcome...remember use helmets.