different brands of dyno also vary, the dyno day wattie was reffering to was on a dynodynamics dyno, which usually read lower than a dynojet dyno.......thats the general rule as far as i've been told by several people. add in weather etc etc......
but as has been said previously, just make sure you use the same dyno to compare if you do mods.....and "i've got more Hp than you" type discussions are only for bragging rights in the pub IMHO, both my bikes are waaaay down on 160 hp but still go fast enough for me.
BTW, i'd like to see the torque and revs as well, thats of more importance