Mikuni VM Throttle Valves
Mikuni supply throttle valves in anodised aluminium and chrome plated brass.
Most aftermarket VM valves are chrome plated brass. Some versions are also available in anodised aluminium.
The smaller the cutaway number, the richer the valve #1.0 rich
The larger the cutaway number, the leaner the valve. #3.5 lean
The throttle valve affects the mixture between 1/8th and 1/2 throttle.
Valves are "handed" depending on which side the idle adjusting screw is located (if fitted)
Contrary to popular belief, the cutaway number (ie. #2.5) is not a measurement in mm
The number comes from the Amal method of identifying the size of the cutaway.
Each whole number on a Mikuni round slide carb represents 1/16" of cutaway from the bottom of the slide to the top of the cutaway.
Each .5 is an additional 1/32"
1.0 cutaway = 1/16"
2.0 cutaway = 2/16"
2.5 cutaway = 5/32"
3.0 cutaway = 3/16"
3.5 cutaway = 7/32"
Strange but true.
Remember if machining the cutaway to not move the point where the cutaway meets the bottom edge.
Most aftermarket VM valves are chrome plated brass. Some versions are also available in anodised aluminium.
The smaller the cutaway number, the richer the valve #1.0 rich
The larger the cutaway number, the leaner the valve. #3.5 lean
The throttle valve affects the mixture between 1/8th and 1/2 throttle.
Valves are "handed" depending on which side the idle adjusting screw is located (if fitted)
Contrary to popular belief, the cutaway number (ie. #2.5) is not a measurement in mm
The number comes from the Amal method of identifying the size of the cutaway.
Each whole number on a Mikuni round slide carb represents 1/16" of cutaway from the bottom of the slide to the top of the cutaway.
Each .5 is an additional 1/32"
1.0 cutaway = 1/16"
2.0 cutaway = 2/16"
2.5 cutaway = 5/32"
3.0 cutaway = 3/16"
3.5 cutaway = 7/32"
Strange but true.
Remember if machining the cutaway to not move the point where the cutaway meets the bottom edge.