im confused by the restrictor. the speedo on my bike will go all the way off the scale, yet it then feels a bit like a restrictor is kicking in when it does. i thought the restrictor was at 180kph/112mph? off the end of the scale would suggest approx 120-125mph

Sounds to me like your bike is deristricted, they don't go much quicker than 125mph

And yes you are right the speed restrictor kicks in at 112.