Ward 143" Big Bore Kit for m8
Description:
If you’re chasing massive power, the Ward Performance 143" Big Bore Kit is the answer. Whether you’re building a monster street bike or a drag-strip machine, this kit delivers incredible performance. With OEM cylinders resleeved to 4.5", forged CP pistons, and optional +2mm Ward CNC ported heads, it’s engineered to dominate. We tested this setup in our own shop, and the results speak for themselves—200 HP and 173 ft-lbs of torque on pump gas, all motor (achieved with +2mm Ward CNC ported heads featuring a 70mm square intake port mod, Burns flush-mount 2" exhaust mod, and our WP143 cam).
The resleeved 4.5" cylinders are bored and honed with torque plates for perfect fitment and long-term durability. These precision-installed ductile iron liners offer massive displacement while maintaining strength, but the engine cases will need to be bored to accommodate the larger liners.
This kit pairs perfectly with our high-performance +2mm Ward CNC ported heads and works seamlessly with optional WP143 and WP143S camshafts, designed specifically for this build. The WP143 cam delivers a more aggressive profile for maximum power, while the WP143S cam offers smoother delivery for street-focused builds. Both options unlock the full potential of the 143" kit, allowing you to tailor your powerband to your riding style.
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Resleeved 4.5" OEM Cylinders: Precision bored and honed with ductile iron liners for long-term durability.
Forged CP Pistons and Rings: Pre-set ring gaps using precision diamond ring filer for easy installation.
Cometic Head and Base Gaskets: Reliable sealing for high-performance builds.
Optional Heads: Available with +2mm Ward CNC ported heads for maximum airflow.
Optional Camshafts: Choose from the WP143 or WP143S camshafts, both designed specifically for this kit.
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Selecting the perfect camshaft, compression ratio, and head configuration can be complex—but we’ve got you covered. With decades of engine development experience, Ward Performance will help you find the perfect combination for your riding style and performance goals. Contact us for more information.
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Still have questions or need help deciding?
No worries! We know performance upgrades can be a big decision, and we're here to help.
If you're unsure about anything, don't hesitate to reach out to us or visit our FAQ page for more information. We're just a message away and ready to assist!
Frequently Asked Questions
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A Big Bore Kit increases your engine's size. This lets your engine take in more fuel and air, creating a much more powerful "explosion" with every stroke. The result? Significantly more horsepower and torque – meaning faster acceleration and more power on the road or track.
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The 143" kit is designed for massive power gains. With the right supporting modifications (like our recommended CNC ported heads and camshafts), this kit has been proven to achieve over 200 HP and 170 ft-lbs of torque on pump gas. While exact results vary, you'll experience a profound increase in performance.
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This 143" kit is a high-performance upgrade that involves precision work. You will need to send in your existing OEM cylinders for our specialized resleeving process. Additionally, your engine cases will require boring to accommodate the larger liners. Professional installation by a qualified mechanic is essential for optimal results.
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To unleash the full, incredible potential of the 143" kit, we highly recommend pairing it with our specifically designed +2MM Ward CNC ported heads and either the WP143 or WP143S Ward Performance camshafts. These components are optimized to work together for maximum airflow, power, and the best riding experience. They are available as optional upgrades.
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Absolutely! Choosing the perfect combination for a build of this caliber can be complex. Our team has decades of experience in engine development and can help you select the ideal setup to match your specific riding goals, whether you're building a street monster or a drag-strip machine. Contact us directly for personalized guidance.
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Custom Forged CP Pistons and rings
Pre-set ring gaps using precision diamond ring filer for easy installation.
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Cometic MLS Head and Base Gaskets
High performance multi-layer-steel composition. Reliable sealing for high-performance builds.
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Optional CNC Ported Heads
Available with Ward CNC ported heads for maximum airflow and power.
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Optional High Performance Camshafts
The WP143 and WP143S camshafts are designed specifically for this kit.