Motion Pro 49mm Fork Cap Wrench

The Motion Pro 08-0429 Fork Cap Wrench is a specialized 2-in-1 suspension service tool engineered for modern dual-chamber, closed-cartridge front forks—most notably Yamaha KYB SSS (Speed Sensitive System) units and select KYB-equipped Honda and Kawasaki models. Servicing closed-cartridge forks requires removing the outer fork cap to access the inner damping cartridge and securing the internal damper rod to remove the lower rebound valve assembly. Using standard open-end adjustable wrenches, steel sockets, or pliers rounds off the delicate aluminum octagonal cap, mars factory anodizing, and slips off narrow damper rod wrench flats.

CNC-machined from 6061-T6 billet aluminum, the 08-0429 combines an octagonal 49mm 8-point box wrench with an integrated 12mm damper rod holding slot. The 8-point box distributes loosening torque across all eight flats of the fork cap simultaneously, preventing localized rounding and thread binding. Centered along the handle, the precision 12mm slot slips securely over the damper rod flats once the fork spring is compressed, holding the rod stationary so the bottom rebound center bolt can be removed without marring the hard-chromed shaft.

Features

• 2-in-1 Suspension Service Tool: Integrates a 49mm 8-point outer cap wrench and a 12mm damper rod holding slot in a single compact profile.

• 49mm 8-Point Octagonal Box: Encloses all eight facets of the fork cap to distribute torque evenly and eliminate rounded edges on soft aluminum caps.

• Integrated 12mm Damper Rod Slot: Captures damper rod wrench flats to prevent rod spin while unthreading the lower rebound base bolt.

• 6061-T6 Billet Aluminum: Delivers the structural rigidity needed to break loose factory-torqued caps while remaining non-marring on anodized components.

• Laser-Engraved Markings: Permanent laser-etched sizing and alignment markings with a durable Motion Pro Blue anodized finish.

• Compact Clearance Profile: Slender handle design clears handlebars and number plates for on-bike cap loosening prior to fork removal.

What's in the Box:

• 1x Motion Pro 49mm / 12mm Fork Cap Wrench for Dual Chamber Forks (Part #08-0429)

Fitment:

• 2016–2026 – Yamaha YZ250X

• 2020–2026 – Yamaha YZ125X

• 2006–2026 – Yamaha WR450F

• 2006–2026 – Yamaha WR250F 

• Fits many other models with a 49mm fork cap.

Fitment Notes:

• Primary Suspension System: Engineered specifically for KYB 48mm closed-cartridge / SSS (Speed Sensitive System) forks and select twin-chamber forks utilizing a 49mm 8-point outer cap and 12mm damper rod flats.

• Incompatible Systems: Doesnot fit Showa 49mm forks requiring a 50mm wrench (e.g., 2017+ CRF450R, 2019+ KX450), WP XACT/XPLOR 48mm forks, or open-bath damper-rod suspension.

• 48mm Fork Tube vs. 49mm Cap Sizing (Common Point of Confusion): The most common mistake DIY mechanics make when selecting tools for Yamaha KYB SSS forks is confusing fork stanchion diameter with cap diameter. KYB SSS suspension uses a 48mm chrome lower stanchion tube, but the threaded aluminum top cap has anoctagonal 49mm outer profile across the flats. Ordering a 48mm wrench will not fit the cap, while a 50mm wrench (designed for newer Showa units) will slip and round the corners. The 08-0429 is the exact tool required for 48mm KYB SSS forks.

• Upper Triple Clamp Pinch Bolt Etiquette: Never attempt to break the 49mm fork cap loose while the upper triple clamp pinch bolts are torqued. The upper clamp applies direct clamping pressure around the outer fork tube precisely where the cap threads mate. Forcing the cap while clamped distorts the aluminum tube and can gall or strip the ultra-fine M47/M48 threads.Loosen the upper triple clamp pinch bolts first, leave the lower clamp bolts torqued to keep the fork leg from rotating, crack the cap loose 1/4 to 1/2 turn using the 08-0429, and then loosen the lower triple clamp to slide the fork leg out.

• Damper Rod Extraction Technique: When removing the bottom rebound center bolt on KYB forks, push down on the outer tube to compress the fork spring and expose the 12mm damper rod flats. Slide the 12mm slot of the 08-0429 over the flats to lock the shaft stationary. Never use steel vice grips, pliers, or channel locks directly on the shaft. Even microscopic tooth marks or burrs on the damper rod will shred the cartridge seal head and internal o-rings on the rebound stroke, causing total internal damping loss.

• Torque Values on Reassembly: Fork caps require minimal torque to seal because sealing is achieved via an internal radial O-ring, not extreme thread friction. When reinstalling the cap into the outer tube, clean the threads, lubricate the O-ring with fresh suspension fluid, and tighten the cap to22 lb-ft (30 Nm). Once installed in the triple clamps, torque upper triple clamp pinch bolts to factory specification (typically15–17 lb-ft / 20–23 Nm). Over-torquing triple clamp pinch bolts binds the internal outer tube, creating mid-stroke suspension harshness and stiction.

Part Number: 08-0429