| 57 Sounds a bit on the low side, so worth getting it setup properly, cam timing needs to be identical for each cylinder and once thats sorted get the fuel mapping sorted.
I did have a 2002 engine that I never managed to get more than 59bhp out of no matter what I tried, the engine I've been using for the last coup[le of years started off making 63bhp and over time has dropped a couple of bhp but that doesn't tell the whole story. Although only a couple of bhp down it feels as though its missing a lot more in the way it accelerates.
Checkout the Desmo Due Paddock on Facebook | 
skidlids
Threaded Mode