If looking for more power for your Z125, you’ve come to the right place! The parts in this kit were developed to work flawlessly with each other to deliver a high level of performance at an affordable price. While we sell each part of this kit separately, running the combination of the big bore kit, race head, and intake kit is where you will see the most power and performance gains for the best value.   These are high quality parts and the increased power will not disappoint. Here’s whats included in this kit:

143cc Big Bore Kit:

• 60mm Ceramic coated all aluminum cylinder (no steel sleeve)
• Lightweight high compression domed 60mm piston with rings, pin, & clips (will safely run on pump gas, 90-93 octane)
• Head gasket kit – Now includes the cylinder head o-ring set and an exhaust gasket.

The all aluminum ceramic coated cylinder is not only lighter than a steel sleeved aluminum cylinder, it is harder, reduces friction (increasing power), improves sealing, and provides better heat transfer (runs cooler and cools down quicker).  Additionally,  this is the biggest bore kit you can install without needing machining to the cases (case boring).

Race Head V2:

• Forged anodized aluminum roller rockers
• Huge 30mm intake and 24.5mm exhaust valves
• Stainless Steel Valves (21-4N material)
• 27mm intake port, 23mm exhaust port
• Race Camshaft V2-1 (TBW0473)
• Cam Sprocket

The combination of the above features in this Race Head V2 deliver huge power gains over the stock basic OEM cylinder head.

Intake Manifold Kit:

• Port matched to the Race Head V2
• Enlarged 26mm port on throttle body side to work better with bored throttle bodies (also works well with stock throttle body)
• Includes a port matched heat stop to prevent heat transfer to the intake (cannot run a heat stop with the stock intake manifold and some aftermarket head spacers)
• Includes all mounting hardware
• Includes a heat sensor extension harness so it can be relocated to the tappet or cam cover.

This intake manifold will ensure you will get the most power out of the Race Head V2!

Add a stroker crankshaft for even more power!  Our 55mm stroker crank increases engine displacement and compression.  If you add it to the:

143cc Big Bore Kit, will increase displacement to 155cc
165cc Big Bore Kit, will increase displacement to 177cc
178cc Big Bore Kit, will increase displacement to 194cc

Important Information:

There are no installation instructions, but if you can replace your piston, you can install this kit as the parts are installed in the same manner as the OEM parts.  However, its highly recommended that a professional technician install this kit and make sure its tuned properly – An aftermarket fuel controller is required and possibly an autotune will be needed to prevent a lean condition and damage to your engine.  A performance exhaust is also recommended as the stock exhaust is restrictive and may cause your engine to run hotter.

This product is legal for closed-course competition use only; for racing vehicles (a competition vehicle not used on public highways). Intended for off-road use or race purposes; may not meet regulations of pollution controlled roads or highways. Not legal for vehicles registered and used in California.