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1978 Honda CB400A Carburetor Tools

A two-gauge synchronizer lets the two carburetors be compared during the appropriate service procedure. This universal kit supplies the gauges and connection hardware, but the CB400A’s cylinder-head vacuum test connections still need checking. A modified intake may require a different adapter arrangement.

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Universal motorcycle carburetor synchronizer vacuum gauge 2 carb synchronizer

Universal Motorcycle Carburetor Synchronizer Vacuum Gauge ~ 2 Carb Synchronizer

$54.95 USD
37-0003
Carburetor and throttle body synchronizer kit for bikes with 2 Carbs. Makes synching your carburetor setup fast and easy! For use with Honda, Kawasaki,...
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1978 Honda CB400A · Carburetor Tools Buying guide

Match the cylinder-head vacuum test connections

The kit includes two gauges, a mounting bracket, hoses, damping valves, instructions and two lengths of 5 mm-thread extensions. Establish the correct connection points and follow Honda’s setup procedure before starting the adjustment.

Parts to consider

Universal Motorcycle Carburetor Synchronizer Vacuum Gauge ~ 2 Carb Synchronizer Universal two-carb synchronizerTwo gauges, bracket, hoses, damping valves and 5 mm-thread extension adapters are included.View part

Review the included pieces

Two gauges, their mounting bracket, hoses and damping valves are included, along with 65 mm and 180 mm extensions using 5 mm threads. Honda’s original CB400A procedure places the adapters in the cylinder head. Check those connections before choosing extension length; the universal label does not establish stock adapter-thread compatibility.

Use the right procedure for the fitted carburetors

Honda service information provides the setup and adjustment sequence for the original carburetors. If another carburetor set has been installed, use its relevant documentation as well. The gauge kit compares vacuum; it does not replace the checks needed to establish a sound carburetor installation.

Carburetor Tools questions

What does the kit include?

It includes two gauges, a mounting bracket, hoses, damping valves, instructions and 180 mm plus 65 mm extensions with 5 mm threads. Check those adapter threads against the cylinder-head vacuum test connections before ordering.

Will it connect to any pair of carburetors?

No universal thread compatibility is promised. The supplied extensions have 5 mm threads. Confirm the cylinder-head vacuum test connections for the original CB400A setup, or the specified test points after an intake conversion. Resolve any adapter mismatch before using the tool.

What are the damping valves for?

They help control gauge-needle movement during use. Follow the tool’s instructions for their operation and Honda’s procedure for the motorcycle setup; do not treat damping adjustment as the carburetor synchronization adjustment itself.

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