Saihisday Front Brake Master Cylinder for Yamaha ATV — Right-Side, 1.4 cm Piston Bore, 7/8" Clamp

This replacement master cylinder is designed to match the factory fit and function for a wide range of Yamaha all-terrain vehicles including Banshee, Big Bear, Grizzly, Kodiak, Raptor, Timberwolf, Wolverine, and YFZ450 models from the late 1980s through the 2010s. Built with a 1.4 cm piston bore and a 7/8" (22 mm) handlebar clamp, it uses a 10x1.25 mm banjo bolt and ships ready to install on the right side, oriented to face the front tire direction. The Saihisday unit comes as a single-piece replacement (part number 4WV-25870-00-00 equivalent) and is meant for riders seeking a straightforward brake component swap without custom modification.

How does this master cylinder match my Yamaha ATV?

The Saihisday unit is engineered to the same basic dimensions and mounting points used by many Yamaha front brake master cylinders. It aligns with the standard handlebar diameter and banjo bolt thread common on the listed model years, so no re-machining is normally required. If your original part number is 4WV-25870-00-00 or your bike is listed among the compatible models, this unit is intended to be a fit-for-purpose replacement.

• Piston bore: 1.4 cm to replicate original hydraulic response.
• Handlebar clamp: 7/8" (22 mm) for direct mounting.
• Banjo bolt thread: 10x1.25 mm for hose compatibility.
• Right-side orientation, facing the front tire as OEM.

What should I expect during installation?

Installation is described as plug-and-play for most users and typically takes 30 minutes or less when performed by someone familiar with basic brake work. You will need to remove the old master cylinder, transfer or replace the brake hose with the correct banjo bolt, mount the clamp to the handlebar, and bleed the system to remove air. Follow professional procedures and recommended torque specifications to ensure safe operation.

• Estimated install time: ~30 minutes for experienced hands.
• Mounts on the right handlebar; aligns facing front tire direction.
• Requires bleeding the brake system after installation.
• Use correct 10x1.25 mm banjo bolt and recommended brake fluid.

Which specific Yamaha models and years are covered?

This master cylinder covers a broad set of Yamaha ATVs across multiple generations where the OEM part number or dimensions match. Key compatible models include Banshee 350, Big Bear 450/400/350/250, Grizzly, Kodiak 450, Raptor, Timberwolf, Wolverine and YFZ450 over the years noted. Always cross-check your original part number and fit points before purchase.

• Banshee 350: 1987–2006 compatibility range.
• Big Bear: 450 (2007–2014), 400 (2000–2012), 350 (1987–1999), 250 (2007–2009).
• Kodiak/Grizzly/Raptor/Timberwolf/Wolverine and YFZ450 across listed years.
• Replacement reference: 4WV-25870-00-00 for verification.

Who is this for: This replacement master cylinder is aimed at ATV owners, mechanics, and restoration projects that require a reliable, dimensionally compatible front brake master cylinder for Yamaha machines. It's well suited for riders wanting a direct-fit part that restores lever feel and brake responsiveness, and for shops performing routine brake component replacements. If you are unsure about compatibility, compare the piston bore (1.4 cm), handlebar clamp size (7/8" / 22 mm), and banjo bolt thread (10x1.25 mm) with your existing unit before ordering. Remember to have the part installed and bled according to professional safety standards.