Most of the modifications listed on this site will effect your bike’s compliance with the ADR’s set out by DOTARS, the government department responsible for such things. Even a gearing change technically breaches the certified specification of the bike. Other mods such as open mufflers, replacement eproms and modified cam timing (other than spec) throw the rule book way out the window. Not to mention the removal of catalytic converters or using super petrol (both of which are looked upon very darkly indeed, so you have been warned).
So, any modifications reported here are FOR OFFROAD OR CLOSED CIRCUIT USE ONLY, AND NOT INTENDED FOR USE ON PUBLIC ROADS. Remember this bit. I will not be held responsible for you getting your good self into the deep end. After all, we are all supposedly old enough to take responsibility for our own actions.
The information on this site is by no means a comprehensive guide to modifying a Ducati, BMW, Cagiva or Guzzi. It is just things I have done that have worked. If you have a better idea, that’s great. If you want to share it, that’s even better. If you think that the performance claims are outrageous, that’s up to you.