We have made some good progress on the bike over the last couple of days. The Thundersport GB Golden Era superbike regs state that 750cc bikes manufactured before 1998 are permitted to be overbored up to a maximum displacement of 860cc. With my bike being a 1997 ZX7R I have taken the opportunity to overbore 1.5mm which takes the displacement up to 779cc. Not quite the 860cc maximum, but there is no larger kit that would be considered reliable.

 The engine is now out and the cylinders are off. They will soon be sent off for the rebore work. 

My dad below examining the cylinders for wear :)