Does 89 EVO have VOE?
Club Member
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From: Bedford UK
VOES = vacuum operated electronic switch, or something like that. It is activated by inlet vacuum, and sends a signal to the ignition module to retard timing on starting and accelerating. What brand of ignition module do you have?
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Cruiser
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As far as I know the bike is stock. And according to the manual, only bikes meant to be sold in California have that. The factory service manual takes about reed valves in the air filter housing, and shows images of them for California models. I just took apart mine on Sunday and it doesn't have anything like that. S&S says I should just cap off that port on the intake manifold. I guess I'll ask HD technical support...
Road Warrior
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From: SoCal & West TN
As far as I know the bike is stock. And according to the manual, only bikes meant to be sold in California have that. The factory service manual takes about reed valves in the air filter housing, and shows images of them for California models. I just took apart mine on Sunday and it doesn't have anything like that. S&S says I should just cap off that port on the intake manifold. I guess I'll ask HD technical support...
The VOE is used on all of the Harley V2 Electronic Control Modules (Electronic Ignition). It was not used on the first Electronic Ignition used by Harley. It was first used on all BT models starting in 1983. (Part number 26555-83 changed in '84 to 26555-84) The VOE controls the two MAP curves in the ECM. it is located between the cylinders and attached to the upper motor mount.
Club Member
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From: Bedford UK
My 1990 FLHS had a VOES (I bought the bike new) and when I swapped to a Crane ignition I retained it. Ran like a bitch when the hose split! So depending on your current set-up it is in my experience an essential item! According to my parts book it is stock on all models from 1984 on.
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Cruiser
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I just checked my books (back to 1980). The reed valves have nothing to do with the Vacuum Operated Electric (VOE) switch. The reed valve was used with the charcoal canister used on all California models.
The VOE is used on all of the Harley V2 Electronic Control Modules (Electronic Ignition). It was not used on the first Electronic Ignition used by Harley. It was first used on all BT models starting in 1983. (Part number 26555-83 changed in '84 to 26555-84) The VOE controls the two MAP curves in the ECM. it is located between the cylinders and attached to the upper motor mount.
The VOE is used on all of the Harley V2 Electronic Control Modules (Electronic Ignition). It was not used on the first Electronic Ignition used by Harley. It was first used on all BT models starting in 1983. (Part number 26555-83 changed in '84 to 26555-84) The VOE controls the two MAP curves in the ECM. it is located between the cylinders and attached to the upper motor mount.
Road Warrior
Joined: Jun 2009
Posts: 1,687
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From: SoCal & West TN
Are you sure you're looking in a Factory Harley manual, and not one of those "Pep Boys" books?
And I don't even see a "VOV" that you are talking about. What is that?
Last edited by Ultra89Rider; Sep 26, 2012 at 12:05 AM. Reason: spelling
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Cruiser
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I don't know what "Factory" service manual you're looking but I have the Harley Davidson Factory Service Manual (99843-90) covering 1984-1990 FLT/FXR Models. The V.O.E.S. starts on page 8-3 with pictures. It talks about where it is located and how the ignition works and how to test it. Then on page 8-11 Titled "Vacuum Operated Electric switch (V.O.E.S.)". It covers how to test the switch. Then on page 8-12 is figure 8-4 showing the complete ignition component, including the V.O.E.S.
Are you sure you're looking in a Factory Harley manual, and not one of those "Pep Boys" books?
And I don't even see a "VOV" that you are talking about. What is that?
Are you sure you're looking in a Factory Harley manual, and not one of those "Pep Boys" books?
And I don't even see a "VOV" that you are talking about. What is that?
VOV is Vacuum Operated Valve that is part of the emission control system on 1988-1991 California models.
Stellar HDF Member
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From: Indiana, USA
You need the VOES to signal spark advance in your ignition module. The Ignition module uses RPM and manifold vacuum to determine spark advance. ie at Wide Open Throttle (WOT) you drop manifold vacuum and the system knows by the signal sent from the VOES (Vacuum Operated Electric Switch ie.Low Pressure Switch)and based on engine RPM the ignition module will decide if advance stays the same or changes. I suppose it would run without the VOES but seems to me your engine would be under powered and wasting fuel at WOT high RPM without the spark advance.
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Cruiser
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You need the VOES to signal spark advance in your ignition module. The Ignition module uses RPM and manifold vacuum to determine spark advance. ie at Wide Open Throttle (WOT) you drop manifold vacuum and the system knows by the signal sent from the VOES (Vacuum Operated Electric Switch ie.Low Pressure Switch)and based on engine RPM the ignition module will decide if advance stays the same or changes. I suppose it would run without the VOES but seems to me your engine would be under powered and wasting fuel at WOT high RPM without the spark advance.
Club Member
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From: Bedford UK
You are looking at a different service manual for a bike I don't own. I have the 84-98 Harley Davidson service manual for the FLH/FLT/FXR Evolution bikes. I own an 89 FLHS. I wouldn't go to Pep Boys if I were you. Too much Chinese crap.
VOV is Vacuum Operated Valve that is part of the emission control system on 1988-1991 California models.
VOV is Vacuum Operated Valve that is part of the emission control system on 1988-1991 California models.
Accept no substitutes......
The VOV you refer to is covered on page 4-47 and illustrated in fig 4-45.
Last edited by grbrown; Sep 26, 2012 at 08:22 AM. Reason: Added para.
