Ahhh I was working with Guzzi in 1978..with the endurance racing team..... That wear at the top of the nigasil (guzzi patent) bore was normal only after 100,000kms + with paper filters or 5000kms running with K&N filters or similar, The bottom end would last with a well maintained motor over 250,000kms ( UNLESS you had the 850T that had NO filteration) where 5000kms would see you with a worn out crank! The crud would fill the cavity in the crank big end journal and then spill into the big end bearings, goodbye crank.....