Pretty sure those are just if you need to bore and honey the cylinders. Not for more power or anything. Just to rectify a problem in the lining.
your bike will run/go heaps better with new rings and pistons, should restore any lost compression. would be good to have a set in the shed for when she starts burning oil
If you do go down this path, I would recommend at least weighing the piston and gudgeon pin and compare to standard. The pin in that image looks very thick, like it is a piece of standard ground bar. The extra weight can lead to broken rods quite quickly. Secondly, replace the circlips with genuine items.
Not likely that I will, was just talking with @Grasshopper last night about ways to improve the FZR. Bigger bores, polish & hone etc
Yeah Compey you are right, but deep inside we all hope that they are ok because genuine costs the planet
