google compression vrs hp chart, plug in current comp/hp vrs 13.5 comp.hp. will answer ur questions about pistons especially for $$$ spent. ur seeking 15-25 hp basically, will not achieve that without a head with int/ex porting, mill, precise valve job that increases valve flow area and total valve seal at high rpm, and some work around valves in combustion chamber to increase flow. the mill and performance vj alone account for close to half the power a ported head makes, commonley referred to as a supersport head .ur doing mods that support each other and necessary for most power.head needs cam, cam needs head if u want it all. if u decide against porting do the mill/valve job minimium, worth about 7-8 hp $300-350. can recommend good
machinist for this. gen 1 tb's need more work, gen 2-3 are pretty good. smothing transistion to primary flies and removing flies/sec rods adds some power. pulling sec flies, leaving rods in just like the zx14, more mid power tuned, but in place naked sec rods cost 2+ hp loss up top. may consider trading up to gen 4 or 5. kaw already done the work.
Last edited by gaz; 04-01-2018 at 08:00 AM.