Depends on the frame and wether you can weld or not. MZ65 is popular but hard to find. KX65, KX80, YZ80 are all popular. A few of us are running scooter pipes. Mine is for a Yamaha Jog and is made by Yasuni. EBay and Amazon have knock offs for a decent price. The MZ65 fitsvthe gas tank frame. Anything else will most likely need cutting and welding to fit.