Twin Power 4.25” M8 Big Bore Cylinders

Twin Power is excited to announce the addition of 4.25” Big Bore Cylinders for M8 models to its product line. Twin Power is known for its high-quality parts and accessories designed for the American V-Twin enthusiast.

Twin Power M8 Big Bore cylinders are factory fitted for the popular Wiseco Black Edition pistons. When combined with Twin Power gaskets, a 107 cubic inch engine can be converted to 124 cubic inches, and a 114 cubic inch to 128 cubic inches. This is strictly a bolt-on kit, as the special gaskets eliminate the need to weld or otherwise modify oil or water passages. Machining of the crankcase is also not required. (*note: It is the engine builder’s responsibility to check and verify all clearances before assembling.) Gasket kits are available with either .030” or .040” thick head gaskets based on the builder’s preference.

The cylinders are offered in a factory style black textured powder coat finish with highlighted fins. Cast-in iron liners ensure strength, durability, and quiet operation. Cylinders are sold in pairs and include cylinder head dowels.

“The M8 has shown incredible performance potential, and this kit really wakes up your stocker,” says James Simonelli, Twin Power Brand Manager. “On a 107” dresser with no headwork, TTS 250 cam and valve springs, 62mm throttle body, a performance intake, and 2:1 exhaust, we achieved 139.63 HP and a whopping 142.65 Ft. Lbs. of torque with a tabletop flat torque curve.”

Twin Power 4.25” M8 Big Bore Cylinders

*Engine was built and tuned by Steve at GMR Performance in Fort Worth Texas.

All the components to complete these kits are available from your local Tucker Powersports dealer.

  • Twin Power 4.25” Big Bore M8 cylinders Part # 486959 | MSRP $449.95
  • Twin Power Gasket kit, .040  – Part # 042123 – $61.79 MSRP
  • Twin Power Gasket kit, .030 –  Part # 042124 – $61.79 MSRP
  • Wiseco Piston Kit, 124” – Part # 162865 – $416.00 MSRP
  • Wiseco Piston Kit, 128” – Part # 162603 – $416.00 MSRP

About Twin Power Since 1982, Twin Power has been designing and producing quality parts and accessories for the American V-Twin enthusiast. Driven by the same passion that fuels the American V-Twin scene, Twin Power is relentless in their pursuit of quality, functionality, and value. They will not offer a Twin Power product to their customers unless they are proud to sport it on one of their own rides. More information can be found at twinpower-usa.com.

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