Honda XR600 & XR650 Mikuni TM40-6 Flatslide Pumper Carb KIT

The Mikuni TM40-6 Pumper Carburetor Kit makes going fast effortless—say goodbye to frustrating hard starts, hesitation, bogging, and flat spots on your Honda XR600 or XR650. This genuine Mikuni flatslide pumper carb is a proven, direct-fit upgrade engineered for these legendary big-bore thumpers, delivering instant throttle snap, smoother acceleration, stronger low- to mid-range torque, and substantial overall horsepower gains.

Complete Kit Includes:

• Genuine Mikuni TM40-6 flatslide carburetor with built-in accelerator pump (pumper) for crisp, lag-free response
• Pre-installed silver anodized airbox adapter (for seamless stock airbox compatibility)
• Pre-installed engine outlet spigot adapter (matches XR intake flange—no mods required)
• 1/4-turn quick-action throttle with matching throttle cables
• Cable choke installed (plus optional knob choke included for versatility)
• Main and pilot jets pre-installed, plus a full range of spare jets for precise fine-tuning

Easy Bolt-On Installation & Tuning

Sized perfectly for the XR600/XR650 platform, the kit bolts right in with pre-fitted adapters—no fabrication, cutting, or major mods needed. Just install, fire it up, and enjoy. The included jet selection lets you dial it in quickly for real-world factors like:

• Climate and elevation changes
• Fuel octane/density variations
• Aftermarket exhaust, cams, big-bore kits, or head porting

Many riders achieve excellent results with minimal adjustments, thanks to the pumper's superior atomization and the flatslide's smoothbore airflow.

Proven Real-World Performance

Dyno tests and rider reports on stock or lightly modified XR600/XR650 engines show power increases of 25% or more in many cases. Expect:

• Lightning-fast throttle response with no lean spots
• Stronger pull from low RPMs through the mid-range
• Smoother, more controllable power across the entire rev range
• Reliable starting and elimination of bogging, stalling, or flat spots

Whether you're ripping trails, desert racing, or building a plated dual-sport beast, this TM40-6 kit brings modern carb tech to your classic Honda XR—transforming it into a more responsive, powerful, and fun machine.

Upgrade your XR today and feel the difference! Questions on jetting, fitment for your specific year/model, or tuning tips? Contact us—we're here to help. SpeedMotoCo.com