Piston kits

[Andrei]

I'm looking to rebuild my CBR. I was only able to find Wiseco piston kit that has 12.4:1 compression ratio standard bore. That's higher than stock. Does this disqualify the bike from supersport class ? ( stock is 12:1)

Does timing need to change if I decide to go with that kit ?

Right now my compression numbers are:
cold and dry : 155 psi
cold with tea spoon oil in the cyl : 190psi
service limit : 178 psi.

[duckracer996]

Not sure about the comperssion change making you illeagle. Don't have a rule book handy. You may just be able to re-ring the motor. Tear it down and check the pistons for skirt collaps and if they are in specs, just re-ring it and your compression should come back up.

[Tornado Bait]

+1mm over is still SS legal.

[Eric Kelcher]

Other than stock compression ratio pistons is NOT SuperSport legal

check with J&E they do custom pistons but OEM may be best choice

[Tornado Bait]

Thanks, Eric.
From the 2009 rule book if anyone wants the exact wording.
6.1 SuperSport
6.1.2
E. Engine modifications include the following:
(1.) Pistons which are no larger than 1mm over stock size may be
used but must be same compression ratio as the OEM piston.