170cc forged bore kit, cam, & dowel pins

TB 170cc, HC, Forged Big Bore & Cam Kit – KLX140

TBparts high compression forged piston 170cc big bore & cam kit. This will make your KLX140 a lot more fun to ride by adding some much needed power! Our new high compression forged piston is dome matched for the stock cylinder head to give you the ultimate high quality performance package. Combine that with our performance cam to really wake that KLX140 up! Our cam opens the valves up faster and provides more lift to let even more air and fuel in for even more power! Great for playbike racing and idles low enough to use on the trails too!

Key Features:

• High Compression Forged piston Kit w/ Wrist Pin, Ring Set, Cir-clips
• Safe with 91+ octane Pump Fuel
• TBparts 63mm aluminum cylinder with HD cast in steel sleeve
• 63mm Top End gasket kit w/NEW dowel pins
• Performance high lift cam, complete with new bearings

Compression ratio on this piston is:

• 10.9:1 – 170cc bore kit combined with the OEM cylinder head
• 12:1 – bore kit w/+6 stroker crank 188cc

In both combinations above, high octane pump gas can be used (Race gas is not required).

Note: 2025+ KLX140s – require case boring to fit. Our cylinder skirt is 65.95mm 2025+ cases are only 65.4mm wide.

There are no installation instructions, but if you can replace your piston, you can install this kit. If you don’t have any experience working on your engine, we highly recommend having a professional technician install this kit or, at a minimum, purchasing the shop manual for your bike available from your local Kawasaki dealer. The parts are installed in the same manner as the OEM parts.

Note – A good jetting base for the factory carburetor is +1 size Pilot jet and +1 or 2 sizes up on the main jet.

Installation note – KLX140 camshaft bolts are reverse threaded, turn them right/clockwise to loosen/remove. Torque to 87 INCH-LBS & Use red thread lock