Hi Nige, nothing done yet, no engine mods, stock cams, carb main jets changed to #115 to go with the zorst, still has original clutch plates. Things not engine related that have been changed are ditching the poxy anti-dive units, swapping the W.W. for cast wheels, (next tyre change the W.W. are going back on), swapping indicators for TL1000 indicators (much cheaper than OEM indicators) and moving them to the lower edge of the cowl, and of course the 4-2 OEM pipes for the 4-1 Yoshi system and solo seat. 630 to 530 chain, shocks and swingarm is about it.
Changing oil and filter every 2,000 km helps .
Cheers.