What is a VOES switch on a Harley?
These letters stand for Vacuum Operated Electric Switch. It senses vacuum behind the butterfly of the carburetor and advances or retards the ignition timing accordingly. The Harley VOES switch remains closed until vacuum is introduced. When closed, the timing is retarded.
How do you test a VOES switch on a Harley Davidson?
It is a simple on off vacuum switch that switches at a specific vacuum. Takes a vacuum source like a MightyVac pump and then your multimeter to check voltage. Watch voltage and then apply vacuum and note the vacuum level when the voltage changes. If that works, then the VOES is fine.
What is a VOES system?
The Vacuum Operated Electric Switch (V.O.E.S.) It senses high and low manifold vacuum and signals the ignition to change its advance slope. Under high load, the switch signals the ignition module to electronically retard ignition timing to reduce the possibility of detonation.
How do you adjust the VOES on a Harley Davidson?
To adjust the VOES to switch at a higher vacuum, turn the adjuster screw 1/4 turn clockwise. Now repeat the test from above to see where (in inches of mercury) the new switch point occurs. If you want it to switch at a lower vacuum level, turn the adjuster screw 1/4 turn counter-clockwise.
What does Voes stand for on a Harley Davidson?
These letters stand for Vacuum Operated Electric Switch. This Harley VOES switch has a very important function on a Harley-Davidson. It senses vacuum behind the butterfly of the carburetor and advances or retards the ignition timing accordingly. The Harley VOES switch remains closed until vacuum is introduced. When closed, the timing is retarded.
Do you need to test your Harley Voes switch?
Take the time to test your Harley VOES. It is also a good idea to be proactive and test during a thorough service. If you find the need to replace your switch it is of utmost importance that you purchase the correct switch for your year and model.
Are there any problems with the voes switches?
The switches are mostly trouble free. The rubber hoses decay with age and the wires are susceptible to chaffing. On your scooter it mounts with the same bolt that mounts the left side of the upper engine locator strut.
How can I Fix my Harley Voes VAC?
Slowly squeeze the handle of the mighty vac. Record how many pounds of vacuum it takes to open the switch. Your meter will beep/ring when the switch opens. If your meter beeps before applying pressure, the switch is no good.