When upgrading engines for more displacement and improved power, a 95mm (or 95cc-equivalent) big bore kit is a popular choice. This guide highlights five well-regarded options suitable for a range of riders—from street-focused Harleys to sport quads. Each section provides a quick overview, key features, and installation considerations to help you compare effectively.
| Product | Brand | Bore/Displacement | Compatibility Notes |
|---|---|---|---|
| S&S 95 in. Twin Cam Big Bore Kit | S&S Cycle | 95 in. (approx. 1,560 cc) | For Harley-Davidson Twin Cam 1999–2006 (excluding 06 FXD). |
| Cylinder Works 40002-K01 Standard Bore Kit | Cylinder Works | 95.5 mm bore; ~400 cc displacement (per kit spec) | Replacement for Suzuki LT-R 450/2006–2009 variants. |
| YFZ450 95 mm Top End Rebuild Kit | Looklardy | 95 mm bore | Applicable to Yamaha YFZ450 2003–2014. |
| Wacece 95 mm Big Bore Kit Head Gasket Set | Wacece | 95 mm bore | For YFZ450 (2004–2013) and WR450F (2003–2006). |
| Tupo 595cc 95 mm Cylinder Piston Kit | Tupo | 95 mm bore; 595cc | Compatible with Yamaha YFM600 family and related models. |
S&S 95 In. Twin Cam Big Bore Kit
The S&S 95 in. Twin Cam Big Bore Kit is designed for Harley-Davidson Twin Cam engines from 1999 to 2006 (excluding some 2006 FXD models). This kit expands displacement to deliver higher torque and increased mid-range power. Features indicate compatibility with S&S 910-0204 components and a focus on street-ready performance. Installation requires attention to cylinder heads, pistons, and gaskets, with a kit approach that typically includes matched components for proper sealing and reliability. This option is a straightforward way to boost displacement on established Twin Cam platforms.
Cylinder Works 40002-K01 Standard Bore Kit
The Cylinder Works standard bore kit specifies a 95.5 mm bore with an 11.7:1 compression ratio, designed as a standard bore kit for Suzuki LT-R 450 models from 2006 to 2009. The kit includes the cylinder, piston kit, and top-end gasket set, with cross-reference notes to Vertex parts. This option emphasizes reliable, factory-aligned components suitable for rear- or race-ready builds, where precise measurements and compatible head gaskets are critical for longevity and performance consistency in mid-range power delivery.
YFZ450 95mm Top End Rebuild Kit
From Looklardy, this 95 mm top-end rebuild kit is designed for Yamaha YFZ450 models spanning 2003–2014. The package lists OEM-like references for piston, rings, pin, clips, gaskets, and springs, along with cylinder barrel components compatible with a wide range of 5TA and related part numbers. The kit targets riders seeking a robust top-end refresh to restore or increase performance on classic YFZ450 platforms, with emphasis on compatibility and complete top-end restoration in one package.
Wacece 95mm Big Bore Head Gasket Kit
Wacece delivers a 95 mm big bore kit focused on a head gasket and top-end rebuild approach for YFZ450 and WR450F platforms (2003–2013 range). The kit emphasizes reliable sealing, durable materials, and improved durability under higher temperatures and pressures. Installation benefits include straightforward alignment with original cylinder positions and a focus on longevity and reduced wear through a comprehensive head-to-block upgrade path.
Tupo 595cc 95mm Cylinder Piston Kit
Tupo’s 595cc kit packs a 95 mm bore with a complete set that includes the cylinder, piston kit, rings, pin, and gasket kit. It is listed as compatible with Yamaha YFM600F and related 600-class models from 1998–2001, and similar Grizzly/XT600 families. This option is positioned for riders seeking a substantial displacement increase on four-stroke Yamaha platforms while maintaining a practical install path with included hardware for a thorough top-end rebuild.
Buying Guide: Key Considerations For Choosing A 95 Big Bore Kit
- Engine compatibility: Confirm bore size, stroke, compression ratio, and the exact model years supported. Kits are often model-specific, and mismatches can cause clearance or sealing issues.
- Displacement goals: 95 mm can manifest as a variety of displacement outcomes depending on engine architecture. Decide whether your aim is higher mid-range torque, top-end horsepower, or a balance for street and track use.
- Quality of components: Look for forged pistons, reliable rings, and properly matched cylinders. A kit with superior gaskets and head components reduces the risk of leaks under higher pressure.
- Installation requirements: Some kits may require refinished cylinders, head work, upgraded studs, or advanced engine tuning. Assess whether you have the tools, experience, or a professional mechanic to complete the install.
- Reliability and maintenance: Higher displacement often increases wear; choose kits that include or recommend compatible maintenance intervals and components like upgraded cooling or oiling systems where applicable.
- Intended use: Street cruising, off-road, or racing each dictate different tolerances for heat, lubrication, and durability. Pack a plan for break-in and tuning accordingly.
- Compatibility with electronics: Some modern engines require ECU tuning or fuel management adjustments after a displacement increase. Plan for possible calibration needs.
- Return policy and support: A robust warranty and vendor support can be valuable when dealing with high-performance parts that require precise fitment.
These options provide a spectrum of 95-based big bore kits across popular platforms, including Harley-Davidson Twin Cam, Suzuki LT-R 450, Yamaha YFZ450, and Yamaha YFM600 families. When selecting, prioritize model-specific fitment, reputable component quality, and a realistic plan for installation and tuning to maximize performance gains and engine longevity.