Help with VOES placement : V-Twin Forum: Harley Davidson Forums

old goat · 10-03-2006, 10:38 PM

Almost have my 91 FXRT ready to go. I can't remember where the VOES bracket mounts. I think that it was attached to the coil mount/stabilizer link bracket. Does the VOES need to be mounted vertical or horizontal? If vertical, which end goes up, the adjustment end or the other end? If anyone can come up with a pic of the way the VOES is mounted it would be greatly appreciated as the service manual and the parts book are of no help.

jduffy01 · 10-03-2006, 11:20 PM

tell me what it is and were and i will take a pic of my 92 fxr for yah

Ed Y · 10-03-2006, 11:48 PM

You're right. It should sit above the motor mount bracket. Doesn't really matter on the orientation of the VOES, it'll work in any position.

Naear · 10-04-2006, 12:05 AM

I mounted mine vertical on the bolt where the stabilizer bolts to the motor mount.

old goat · 10-04-2006, 01:37 AM

Thanks guys. I powder coated a lot of pieces on the bike and got everything else back together in the right place, the VOES had me stumped.

Spent about 3 hours today trying to get the front brakes bled, what an ordeal. Got a set of nearly new 4 piston caliper take offs from a 06 Harley and installed new Russell SS brake lines. New DOT 5 fluid. Tried reverse bleeding, taping the calipers and fittings, and removing the calipers and holding them higher than the master cylinder while reverse and foreward bleeding them. Am at work right now, gonna try again tonight after work. Lever is almost good enough, just can't get that last bit of air out.

Ka-Ka · 10-04-2006, 01:48 AM

I had to find out what the heck a VOES was and came across some reading material. My FXR is an early '84 and does not have one. Frame is tagged December 1983.

Quote:

What is the Vacuum Operated Electrical Switch (VOES)? What does it do and why is it there?

All Harley Davidson motorcycle carbureted models since the 1984 model year have used the VOES to improve throttle response, increase MPG, and meet EPA requirements for emissions.

The VOES is a motorcycle part described as a vacuum ignition retard device. That is, under low vacuum conditions the switch is open and has no effect on ignition timing. Under high vacuum, the switch closes and advances ignition timing. Essentially, the VOES is like the vacuum advance in older type automotive distributors.

The VOES is a normally open vacuum operated switch that closes under 3-5" of vacuum. The switch is connected to a lead from the ignition module. Under high vacuum, 3-5 inches or higher, the switch closes. A lead from the switch to ground closes a circuit in the ignition module. This circuit advances the timing of the spark. The advance increases throttle response and decrease fuel consumption and emissions.

The vacuum hose is usually connected to a port on the carburetor or intake manifold depending on motorcycle year and carburetor. There are several different VOES switches used the mounting bracket style and operating vacuum being the main differences. The FLHT models have a different vacuum range than the other models. However, just about any VOES can be adapted for use by adjusting the point at which the switch closes.

The point at which the switch closes.

The switches can be adjusted by removing the potted plug and adjusting the setscrew. You will need an accurate vacuum gauge and vacuum hand pump. We have been able to set the operating point as low as 2 inches and as high as 7 inches.

Why would you want a VOES?

We have experimented with converting 1972 and later ignitions from points to electronic ignition. We have used Dyna 'S' conversions for H-D's. We have used Crane, Compufire, Spyke and other Harley Davidson conversion kits. With some of these such as the Dyna 'S', you still have to use the mechanical advance system. This requires service and routine maintenance.

Others work very well having digital advances and provisions for a VOES switch. We experimented with installing a VOES in a 1983 FX and found we have improved throttle response and better mileage. We also routinely install the VOES in custom built Harley Davidsons and even our own Kenny Boyce framed Harley FXR's use VOES with a Crane HI4 module. During Dyno runs, we found that part throttle roll on power was increased as was throttle response.

We believe that most street ridden Harley Davidson motorcycles will benefit from a VOES.

For racing applications or supercharged, turbo-charged or bikes using Nitrous Oxide, we do not recommend using a VOES. This is due to the possibility of a sudden timing change causing a backfire which can be a bad thing under these conditions!

godzilla22 · 10-07-2006, 02:52 PM

The main problem with the V.O.E.S. is that they are very prone to premature failure and you really can't tell when they fail for the most part. I run a "Crane Hi-4E" ignition module with digital advance and eliminated the need for the V.O.E.S. I really don't recommend the use of the little electronic ignition modules that mount inside the cam cover (cone) as the area is subject to extreme heat and that tends to cause the module to fail. I ran them when they first came out but I got tired of replacing them every 5000 miles.