Hi, Im a newbie - so be gentle! Ive built a XR650L engined road race bike and have a problem. The gearing is too low. Im running 15/37 (higheest sprocket gearing I can fit!!) with a 17inch rear wheel (160/60 tyre) and the bike is struggling to pull past 105mph due to the engine revving past its peak power. Does anyone else have this problem?? Or know how to fix it cheaply? The engine is making 50HP at 7000rpm so that isnt the problem. I wish to be geared for 120mph or so. Ive checked my primary drive ratios and theyre the lowest gearing so I cant improve that as far as I know. Out of interest, does anyone know what the honda 'power up' clutch gearing is?? Any help is much appreciated.