Mikuni Carb Install

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In this video we will install a Mikuni carb. Mikuni’s HSR42, HSR45 and HSR48 carburetors are some of the finest motorcycle carburetors produced today. An excellent choice for your Evolution or Twin Cam Harley Davidson, they give superb throttle response and deliver all the air flow needed at any level of Harley performance. This owner opted for the HSR45 Easy Kit.

The stock Harley CV40 carburetor flows about 185 CFM (cubic feet per minute) when flow is measured at a pressure difference of 12 inches of water. All the Mikuni carb HSR series flow considerably more:

Stock Harley: 185 CFM
Mikuni HSR42: 213 CFM
Mikuni HSR45: 237 CFM
Mikuni HSR48: 270 CFM

Mikuni carb HSR 42/45/48 smoothbore carburetors also provide highly accurate fuel metering, more power, and Mikuni’s renowned precision throttle response. 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 it mixes more precisely at all throttle settings.

Mikuni’s roller bearing throttle slide offers smoother throttle control and allows the use of a lighter throttle return spring for reduced throttle effort. The Mikuni adjustable accelerator pump provides instant throttle response in any riding or performance application. While a high capacity float bowl prevents fuel starvation even under full throttle applications.

Modified Harley or Harley based engines tend to fall into one of three categories. Decide where your ride falls and choose which Mikuni carb best fits your application.

1) Modified stock — This engine typically has stock cylinder heads, a high flow air cleaner, high flow mufflers, possibly a bolt-in cam. For this type of set up, the Mikuni HSR42 carburetor is a perfect fit.

2) Highly modified — A hotter cam, professional cylinder head port work, a more specialized or tunable exhaust system, high compression pistons. The Mikuni HSR45 carburetor is your best choice.

3) All-out ground pounder — Highly modified heads, a displacement increase, either by way of fitting larger pistons, a stroker kit or both. This engine is more likely to be a special engine, built from the ground up to be stronger and to process more air than even a highly modified Harley motor. This is the sort of motor that should have the HSR48.