Mikuni Carburetor

Mikuni Carburetors: Precision Fuel Delivery for Every Ride

When it comes to carburetion in the powersports world, few names carry as much weight as Mikuni. A staple on the workbenches of serious riders, custom builders, and race mechanics alike, Mikuni has built its reputation around one core principle: getting the air-fuel mixture exactly right — from idle to wide-open throttle. Their lineup of carburetors spans everything from stock-replacement units to purpose-built race carbs, covering motorcycles, ATVs, snowmobiles, personal watercraft, and more.

A Series for Every Application

What sets Mikuni apart in the carburetor category is the sheer breadth and engineering depth of their product families. Each series is designed with a specific rider and application in mind:

• HSR Series (42mm, 45mm, 48mm): The Mikuni HSR Carburetor Series is engineered for serious riders seeking peak performance from idle to wide-open throttle on their American-made V-Twin engines — all without sacrificing reliability. All HSR smoothbore carburetors are designed with an 8-roller bearing flat throttle slide assembly that allows an unobstructed venturi at full throttle to flow more air, while carbureting more precisely at all throttle settings.
• TM Series (Flat Slide): Mikuni's flat-slide TM Series carburetors provide significant performance improvements over older round slide carburetors. Air flows faster and smoother through the TM Series venturi due to the flat slide design and jet blocks, creating a smooth-bore effect with stronger vacuum at the needle jet for more precise metering and better throttle response.
• VM Series (Round Slide): The VM Series stands out for its extensive selection of tuning components, enabling precise fuel mixture adjustments for any application, throttle setting, or riding conditions — a versatility and consistency that has solidified VM Round Slide Carburetors as a trusted choice among riders and engine builders alike.
• BSR & BST Series (Constant Velocity): Mikuni's BSR and BST carburetors are highly regarded for their reliability, smooth operation, and adaptability across a wide range of motorcycles and ATVs, offering seamless throttle transitions that reduce engine stutter or hesitation during acceleration. Their constant velocity (CV) design inherently improves fuel efficiency by maintaining an optimal air-fuel ratio across varying operating conditions.
• RS Series (Radial Flat Slide): The RS Series features a compact design which is 25% lighter than other performance carburetors, offers quick needle jet adjustment, and uses readily available standard Mikuni jets.
• Super BN Series (Watercraft): The High Performance Super BN Carburetors were specially designed to meet the needs of high-horsepower racing watercraft, with greater air flow and fuel flow achieved through extensive testing, and special needle valves and springs for optimum pop-off with large high and low speed jets.

Complete Kits and Tuning Flexibility

Beyond standalone carburetors, Mikuni offers thoughtfully assembled kit options for a range of builds. HSR Series carburetors are available individually, as bolt-on kits that retain your bike's classic look, or as complete kits for serious performance enhancement. For riders who want a turnkey upgrade, Mikuni HSR Total Kits come complete with either a 42mm or 45mm HSR carburetor, a new performance manifold, rubber flange, high-flow air filter, chrome cover, chrome breather kit, and all necessary mounting hardware — with the high-flow air filter capable of supporting up to 100 horsepower without any loss due to air restriction.

For racers at the top end of the power spectrum, the Mikuni HSR48 Race Kit is designed for 120ci or larger engines with high-flow heads and cams, ensuring optimal fuel delivery with an extended main jet and a larger needle valve assembly to meet the demands of high-powered motors.

Whether you're restoring a vintage Japanese twin, building a custom V-Twin, or extracting every last horsepower from a race engine, Mikuni's carburetor lineup offers the engineering precision, tuning depth, and proven reliability that powersports enthusiasts have trusted for decades. Explore the full Mikuni brand catalog or browse all carburetors to find your perfect match.