HSR Carburetors Series

Mikuni Racing Carburetors

Smoothbore Carburetors

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. Offered in 42, 45, and 48mm throttle bore sizes, HSR Series carburetors deliver better throttle response, more torque, and more horsepower. Available individually, as bolt-on kits that retain your bike’s classic look, or as complete kits for serious performance enhancement. Built to provide smooth, steady acceleration and a significant horsepower boost, the HSR series gives you everything needed to fine-tune your ride and elevate your experience on the open road.

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Available Carburetors

Individual Carburetors

Mikuni HSR Carburetors are designed for performance engine builders who need a standalone carburetor for custom and race applications. These carburetors are available in both standard aluminum and polished finishes to suit various aesthetic and functional preferences. Each carburetor includes a choke cable, except for the TM42-6 model, which utilizes the stock choke cable from a CV-type carburetor. Choke cables are available separately.

TM42‐6

HSR 42mm Carburetor (standard finish)

TM42‐6PK

HSR 42mm Carburetor (polished)

TM45-2

HSR 45mm Carburetor (standard finish)

TM45‐2K

HSR 45mm Carburetor (standard finish) with Choke Cable

TM45‐2PK

HSR 45mm Carburetor (polished)

Mikuni Easy Kits

Mikuni Easy Kits are designed to preserve the stock appearance of your bike while offering enhanced performance gains. These kits work with the original Harley-Davidson intake manifold, choke cable, air cleaner, and throttle cables, ensuring a perfect fit without altering the bike’s classic look. Each kit includes a specialized adapter for high-performance air filters. Additionally, California A.R.B. Legal Kits are available for EVO Big Twin applications, ensuring compliance with state emissions regulations.

42-7

HSR42 Easy Kit for 1990 to 1999 1340 Big Twin Evo with stock CV type manifold

42-18

HSR42 Easy Kit for 1999 to present Twin Cam, 1990 to ‘99 Big Twin Evo

45-5

HSR45 Easy Kit for 1999 to present Twin Cam, 1990 to ‘99 Big Twin Evo

42-10

HSR42 Easy Kit for 1994 to 2004 Sportster 1200

42-11

HSR42 Easy Kit for 1994 to 2006 Sportster 1200, Buell models

42-6

HSR42 CA Legal Kit for 1990 to 1998 1340 Big Twin Evolution models sold in California

Mikuni HSR Total Kits

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. The high-flow air filter is capable of supporting up to 100 horsepower without any loss due to air restriction. These kits are compatible with stock throttle cables from 1992 and later models, though manifold clamps and seals are not included.

42‐8

HSR42 Total Kit for 1984 to 1999 1340 Big Twin Evo

42‐19

HSR42 Total Kit for 1999 to present Twin Cam 88/95

45‐2

HSR45 Total Kit for 1984 to 1999 1340 Big Twin Evo

45‐3

HSR45 Total Kit for 1984 to 1999 1340 Big Twin Evo

45‐4

HSR45 Total Kit for 1999 to present Twin Cam 88/95Race Kits

Mikuni HSR48 Race Kits

The Mikuni HSR48 Race Kit offers unparalleled airflow and precise fuel metering, delivering maximum power and responsive throttle control for serious race engine builders and performance enthusiasts. Designed for 120ci or larger engines with high-flow heads and cams, this kit ensures optimal fuel delivery with an extended main jet and a larger needle valve assembly, catering to the demands of high-powered motors. The kit includes a 48mm smoothbore carburetor, rubber mounting flange (with 78mm bolt hole centers), choke cable, and four main jets. It utilizes stock Harley CV-type cables and is intended for use by experienced builders. Please note that the manifold and air filter are not included.

48-2

HSR48 Standard Race Kit

48-2P

HSR48 Polished Race Kit