I had gotten the bicycle to get around when I had trouble with my transmission in my square body truck. After seeing someone with a motor on their bike, I decided to get one off ebay. This is an 80cc kit on a Huffy Rock Creek 26" mountain bike. I have an offset intake manifold I chopped off the end to make the carburetor fit. I cut an inner tube to cushion vibration at the motor mounts & gas tank. I don't know the exact speed I'm topping out at, but it's pretty fast !! I drilled a hole in the bottom of the muffler & drilled holes into the black carburetor filter cover. I don't see any problem not running that chain guard. I also took the cover off to lube the gears & the clutch bar thing in front of the ball bearing. This whole setup cost my about $250 with everything.