TB Parts 143cc Big Bore Kit Kawasaki Z125 (Stock Head)

TB 143cc Big Bore Kit (60mm) – KLX110 & Z125

Unleash the true potential of your Kawasaki KLX110 or Z125 with the TBparts 143cc Big Bore Kit! Designed for easy installation with no case boring required, this high-quality kit is a bolt-on upgrade that delivers over 50% more power while maintaining reliability on pump gas (90-93 octane).

Performance-Driven Design

At the heart of this kit is a lightweight, ceramic-coated aluminum cylinder, engineered for superior heat dissipation, reduced friction, and enhanced sealing—allowing your engine to run cooler and more efficiently. Paired with a high-compression 10.5:1, 60mm piston (7mm larger than stock), this setup is built to maximize horsepower while remaining 91+ octane pump gas friendly.

What’s Included?

• 60mm Ceramic-Coated Aluminum Cylinder – Lighter and more efficient than steel-sleeved alternatives
• High-Compression Domed Piston (10.5:1) – Complete with rings, pin, and clips
• Top-End Gasket Kit – Now includes new dowel pins for seamless installation
• No Case Boring Needed – Bolt on and go!

Installation & Tuning

If you can replace a piston, you can install this kit! However, professional installation or a shop manual is recommended if you're new to engine work. OEM-style installation ensures a straightforward upgrade.

KLX110 Jetting Recommendations:

• Stock Exhaust: Pilot Jet #40 or #42, Main Jet #85 or #90
• Aftermarket Exhaust: Pilot Jet #42, Main Jet #90, #92, or #95
• Jet Kits: TBW1458 (Pilot), TBW0294 & TBW1584 (Main)

Z125 Tuning Note:

A fuel controller is required to prevent running lean. With proper tuning, good fuel, and reasonable riding conditions, these kits have been tested for 8,000+ miles of reliable performance.

Upgrade your ride today and feel the difference in power, performance, and responsiveness with the TBparts 143cc Big Bore Kit!