V.o.e.s.
V.o.e.s.
As stated in another thread, I've upgraded to an EV13 cam, had issues with new lifters etc. Getting things sorted out is a learning process. Got the bike running with OEM lifters (for now).
Was having issues with 'surging' at idle and cruising at lower RPM's. I unplugged the VOES and the surging stopped. So I spent the last week (+) investigating/studying/learning about this and here's what I've figured out:
Factory VOES is 3 in. Hg. They are adjustable but only up to 4 in. Hg. That seems to help a lot but not completely fixing the problem. I just ordered another VOES that suppose to be set at 5 in. Hg.
I understand the VOES works just like the vacuum advance on the side of the distributor on a 1973 Chevy 350ci motor.
What else can you guys teach me about the VOES? Will a 5 in. Hg VOES be correct? Am I missing anything?
Was having issues with 'surging' at idle and cruising at lower RPM's. I unplugged the VOES and the surging stopped. So I spent the last week (+) investigating/studying/learning about this and here's what I've figured out:
Factory VOES is 3 in. Hg. They are adjustable but only up to 4 in. Hg. That seems to help a lot but not completely fixing the problem. I just ordered another VOES that suppose to be set at 5 in. Hg.
I understand the VOES works just like the vacuum advance on the side of the distributor on a 1973 Chevy 350ci motor.
What else can you guys teach me about the VOES? Will a 5 in. Hg VOES be correct? Am I missing anything?
Seasoned HDF Member
Joined: Apr 2008
Posts: 23,053
Likes: 12,327
From: Arkansas
I cant teach you anything but can tell you what I recently did.
I was having issues with poor drivability when the engine would get up to operating temps.
I replaced everything from the cone to module with the exception of the VOES which I hadnt even thought about.
After it occurred to me it could be the culprit, I removed it and since I dont have a vacuum gauge, I took it to a shop and asked him to check it.
It was OK when at room temperature but after heating it up, it started going in and out. I asked if they had one in stock which they did but the wrench told me just leave the fkr off and cap the port on the manifold.
I commented that its always been my understanding that doing away with the VIES would cause detonation but he said hes been without one for years with no issues.
I took his advice and didnt replace it.
Bike is running great and no indication of any detonation so far.
I was having issues with poor drivability when the engine would get up to operating temps.
I replaced everything from the cone to module with the exception of the VOES which I hadnt even thought about.
After it occurred to me it could be the culprit, I removed it and since I dont have a vacuum gauge, I took it to a shop and asked him to check it.
It was OK when at room temperature but after heating it up, it started going in and out. I asked if they had one in stock which they did but the wrench told me just leave the fkr off and cap the port on the manifold.
I commented that its always been my understanding that doing away with the VIES would cause detonation but he said hes been without one for years with no issues.
I took his advice and didnt replace it.
Bike is running great and no indication of any detonation so far.
HDF Community Team
Joined: Dec 2005
Posts: 5,404
Likes: 2,605
From: NC USA
The VOES for the Touring models were supposed to be 5hg or thereabouts. They do not work like a vacuum advance on an ignition distributor. It's simply an on/off switch. On with vacuum, off without. It sends a ground signal to the ignition module, telling it to advance the timing to a programmed value based on rpms.
Basically, with vacuum and above approx 2000 rpms, the module is operating in full advance, which under normal conditions is 90% of the time or more.
Several things can cause surging but I'll leave that for another time.
*Iron if you put one on, set the timing correctly, it'll get much better fuel mileage. But won't affect the running or power above 3000 rpms. A bad switch won't cause detonation, that's most often an intake leak if the base timing is correct.
Basically, with vacuum and above approx 2000 rpms, the module is operating in full advance, which under normal conditions is 90% of the time or more.
Several things can cause surging but I'll leave that for another time.
*Iron if you put one on, set the timing correctly, it'll get much better fuel mileage. But won't affect the running or power above 3000 rpms. A bad switch won't cause detonation, that's most often an intake leak if the base timing is correct.
Last edited by t150vej; Aug 12, 2022 at 12:49 PM.
HDF Community Team
Joined: Dec 2005
Posts: 5,404
Likes: 2,605
From: NC USA
If the base timing is not moved then no, what you were told is incorrect.
But if you disconnect it and ground the wire that connects it to the ignition module, the module will operate at full advance at all times which can cause spark knock/detonation.
But if you disconnect it and ground the wire that connects it to the ignition module, the module will operate at full advance at all times which can cause spark knock/detonation.
Road Master
Joined: Oct 2019
Posts: 932
Likes: 592
From: Connecticut
The VOES can be 'calibrated' to switch at a higher or lower vacuum. Had to do it on my evo sporty build to 'dial' out some pinging issues.
Here's some relevant reading.
http://xlforum.net/forums/showthread.php?t=1863153
Here's some relevant reading.
http://xlforum.net/forums/showthread.php?t=1863153
Trending Topics
Club Member
Joined: Sep 2010
Posts: 15,429
Likes: 7,122
From: Beyond Fucital
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Cruiser
Joined: Apr 2020
Posts: 111
Likes: 45
From: australia
pretty sure its the WOT curve that will be selected which advances pretty quickly through the rev range. i imagine Harley factory ignition operates in the exact two curve methods but who knows what and when those advance rates are.( well its probably in the manual) At least with Ultima and S&S you can program or select a less aggressive single curve.
I have purchased a Daytona Twin Tec VOES kit ready to install on my fresh 113 (when its Finished
), I can confirm it switches at 5 or just above as I've tested it on my vac pump.If your wondering why some would say No Voes "my bike doesn't Ping or Knock" and others would say their bikes pinged and knocked with out it is because their is so many factors that can contribute, such as fuel octane, air fuel ratio, what is the max advance degree of the single curve, how many cubes is your engine. compression ratio Etc.
Last edited by Ozzie John; Aug 12, 2022 at 06:27 PM.
Intermediate
Joined: Jul 2022
Posts: 41
Likes: 26
From: Earth
Id be interested in learning if anyone else has ditched the voes for a mechanical advance and if so if youve had any problems. I have run a centrifugal advance on my 88FLST for 10 or 15 years so far with a dynaS single fire ignition.
Apologies for the thread hijack but maybe this is something others will want to look into or conversely maybe someone will post why its a bad idea.
Apologies for the thread hijack but maybe this is something others will want to look into or conversely maybe someone will post why its a bad idea.