well years ago i tuned one for a laugh and it went like the wind i port and polished it, polished carb, up jetted, had head skimmed, k and n air filter, upgraded valve springs so it didnt vibrate as easy at top revs, changed spockets but because of this had a few problems starting it due to battery always goin dead because there was to much compression on starter motor also kept taking it off clock and eventually blew side casing off which covers cam however she did still run after it