TB 143cc big bore kit with V2 Big Valve Race Head! The 60mm bore is the biggest kit to run on the z125 Pro without machining your cases. Bolt-on ready, no machine work needed. Just add a Fuel controller. Comes with TB Intake Manifold. 
V2 Race Head
28mm intake valve
23mm exhaust valve
25mm intake port
21mm exhaust port (valves installed).
Race Camshaft for Race Head V2 with cam gear
Head Gasket Set
 
You will need a new manifold to run this head on your Z125Pro
CHIMERA INTAKE MANIFOLD/ADAPTER WITH INJECTOR FOR KAWASAKI Z125 BIG BORE ENGINE (CH-1111) OR
TB PERFORMANCE INTAKE KIT FOR V2 RACE HEAD - KAWASAKI Z125 (HTB-1022)
Additional recommended operational parts:
Oil Cooler
Aftermarket Fuel Controller: Bazzaz Z-Fi or Dynojet Powercommander V w/Autotune (for those who don't have access to a dynameter)
Upgraded clutch parts: performance clutch springs and/or clutch disc
Big Bore Cylinder 143cc - 165cc
Optional parts for higher performance:
Bored out throttle bodies
Aftermarket exhaust system
Chimera Short Ram Intake System
Professional installation is highly recommended!
Engine break-in, aftermarket fuel controller and special tune/autotune is required! Likewise with any major engine modification or bore up kits, it's now considered a high-performance race engine, extra attention and steps are needed to maintain a high-performance engine.