TBParts 143cc Big Bore Kit (60mm) – Kawasaki KLX110 (All Models) & Z125

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

A true bolt-on big bore upgrade for all Kawasaki KLX110 models and the Z125 — no case boring, no machining, no modifications required. The TBParts 143cc kit pairs a ceramic-coated all-aluminum 60mm cylinder with a lightweight high-compression piston for power gains of over 50% on pump gas. High quality parts, straightforward installation, and an outstanding value.

Kit Specifications

• 60mm bore — 7mm larger than the stock 53mm piston
• 10.5:1 high compression domed piston with rings, pin & clips
• Ceramic-coated all-aluminum cylinder (no steel sleeve) — lighter, lower friction, better heat transfer
• Compatible with stock, Zongchen ZS, and older V1 cylinder heads
• Runs on 91+ octane pump gas
• Head gasket kit with new dowel pins included
• No case boring required — bolt on and go

Jetting & Tuning

KLX110 (Carbureted): Base tune — Pilot jet #40 or #42, main jet #85 or #90. With aftermarket exhaust: Pilot #42, main #90, #92, or #95.

• Pilot jet kit: TBW1458
• Main jet kit: TBW0294 & TBW1584

Kawasaki Z125 (Fuel Injected): An aftermarket fuel controller is required to prevent running lean. TBParts does not sell or provide tuning files for the Z125.

With proper tuning, good fuel, and reasonable riding conditions, 8,000+ miles have been documented on these kits.

Installation Notes

Parts install in the same manner as OEM components. No instructions are included — if you can replace a piston, you can install this kit. If you have no engine experience, professional installation or the Kawasaki shop manual is strongly recommended. See the TBParts Kawasaki Tech Section for FAQs.

Fitment

• Kawasaki KLX110 — All Models & Years
• Kawasaki Z125 Pro — All Years