Mikuni Carburetor Rebuild Kit for Yamaha GP/XL – MK‑BN44I‑YAM, rebuild parts for Super BN44i/BN46i (gaskets & diaphragms)

Complete rebuild components for one Mikuni Super BN44i or BN46i carburetor used in select Yamaha GP and XL personal watercraft (needle valve not included).

If your Yamaha GP or XL-series personal watercraft is running rough, leaking, or showing poor throttle response, the Mikuni MK-BN44I-YAM rebuild kit supplies the common wear parts needed to restore carburetor performance. This genuine Mikuni kit contains gaskets, diaphragms, seals, O-rings, and hardware intended to rebuild one Super BN44i or BN46i carb fitted with the factory Power Valve System. It is tailored for specific Yamaha models from the late 1990s to mid-2000s and helps refresh the carburetor without replacing the entire unit.

Which Yamaha models and years will this rebuild kit fit?

This kit is matched to Yamaha personal watercraft that originally used the Mikuni Super BN44i or BN46i carburetors with power valves. It supports a range of GP, GP800R, GP1200R, XL and XLT models produced around 1998–2005. Confirm your carburetor type and engine compatibility before purchasing to ensure a correct fit.

• 2000–2002 Yamaha GP1200R
• 1998–2000 and 2000–2005 versions of GP800/GP800R
• 1998 Yamaha XL1200, 2001 Yamaha XL800, 2001 XLT1200
• 2002–2004 Yamaha XLT800

What parts are included, and what’s intentionally excluded?

The MK-BN44I-YAM kit contains the typical consumables needed to rebuild a single carburetor: a selection of gaskets, diaphragms, seals, and small hardware pieces that age and fail over time. It does not contain main jets, pilot jets, or needles, because those items vary by application and are replaced separately when tuning or correcting fuel mixture. Also note the needle valve is not provided in this kit.

• Included: gaskets, diaphragms, seals, O-rings, and mounting hardware
• Not included: main jets, pilot jets, needles, needle valve
• Designed for one Mikuni Super BN44i or BN46i carburetor

How will installing this kit affect engine performance?

Replacing worn carburetor consumables restores sealing and diaphragm function, which stabilizes fuel delivery and throttle response. While the kit alone won’t change jetting or tuning, fresh seals and diaphragms reduce leaks and erratic idle, helping the engine run more consistently across load and RPM ranges. Proper installation and inspection of other fuel-system parts are recommended for best results.

• Improves throttle consistency and idle stability
• Stops vacuum and fuel leaks caused by cracked gaskets/diaphragms
• Prepares carburetor for accurate jetting and tuning if needed

What should you check or prepare before rebuilding?

Before you begin, verify the carb model (BN44i or BN46i) and inspect for damage like warped bodies, corroded passages, or broken power valve components that a kit cannot fix. Gather basic tools, a clean workspace, carb-cleaning solvent, and replacement jets or needle valves if your troubleshooting indicates fuel metering parts need changing. Follow a step-by-step rebuild guide or factory manual to ensure correct reassembly and clear float/air passages.

• Confirm carburetor type and Power Valve compatibility
• Inspect carb body and power valve for damage
• Have cleaning solvent and basic tools ready—service manual recommended

Who is this for? The Mikuni MK-BN44I-YAM rebuild kit is aimed at watercraft owners, marine technicians, and DIY mechanics who want to refresh the fuel-delivery components on one Mikuni Super BN44i or BN46i carburetor from compatible Yamaha GP/XL/XLT personal watercraft. It’s ideal when diaphragms, gaskets, or seals are degraded but the carburetor body and power valve system remain serviceable. For complete fuel-system overhaul or jet changes, purchase the appropriate jets or needle valve separately.