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--- Quote from: Ajayrk on Wednesday, June 27, 2012. 08:51:00 AM. ---You are making this too complicated....

--- End quote ---
For sure.
IF you do not have the technical experience and the tools to measure results the only thing you can effectively do is:
1) Replace the ignition timing plate EXACTLY where it was.

> after loaded test riding in the hottest weather you expect to encounter...

2) Advance the plate 1 hash mark.

> load-test ride new timing set point...

3) Repeat the same change until you encounter pinging when load tested.

IF there is no improvement from advancing timing, try going the opposite direction (retarding) testing for power increase.

This is the best advice I can offer for SOP tuning...which can only be ballpark at best.

Careful with too much advance OR retard as damage can be done if run long enough too far either way.


--- Quote from: Ajayrk on Wednesday, June 27, 2012. 08:51:00 AM. ---You are making this too complicated.

What do you want to do with the timing?
What ignition system are you using.
And to further confuse you the cam turns at half the speed of the fly wheel, sooo what ever changes you make with the timing plate is doubled at the fly wheel.

Stock factory timing is 35* (the asterisk is for degrees) BTDC.  How much further advance do you want to go?

--- End quote ---

What do I want to do with the timing and what ignition module am I using?

Great question, right now that's a perfect question, actually I have no predetermined desires to do anything with the timing other than saying here is what I have, and what am I looking at and what do I need to be concerned about, for example, do I just put the cam position sensor plate back together in the exact same spot that it was the previous two cam changes, or is that absolutely ridiculous. AND I Should be considering some sort of rotation?

Last August I changed the ignition module from the stock HD# 32449-95A to a FXRP IGNITION MODUEL HD# 32419-91A which also required a Custom Chrome Adapter CC#12568 for proper plug and play.

CLICK HERE: 101 Harley-Davidson Evolution Performance Projects, Pages 208-210, 213

Excerpts from the Author's book:

What you need to know is that strong running Harley Big Twins usually need more aggressive curves than they come with stock.  The only "factory" modules for Big Twins that offer a different advance curve are the shovel head module, the so-called "HDI" (International) module, the "Police" module, and the SE modules. 

HD# 32419-91A Police FXRP Evo 1340 5,800 RPM-Limit E-Curve
Police module, uses a VOES and offers solid performance.  It boasts a slightly better curve (E) and limits revs to 5,800 RPM.

The motor company did their homework on this one and came up with a pretty good compromise.  This module is "less prone to "ignition-related misfires and shuts the motor down just as the stock heads quit flowing and the stock valve springs start bouncing". 

E-Curve Subtle differences in the curve, but enough to prevent pinging, even in the most high compression motors.  A little known bit of trivia:  the 1985 California Highway Patrol (CHIP) police bikes were built with .050 thousandths milled off of the heads, 0.15 off of the cylinders, and no smog stuff whatsoever.  This module kept them in one piece through many, many miles.

The "P"-Curve is the OEM Ignition Module for my 1999 FXR2 and for all CVO FXR's HD#32449--95A
No graph is available for this latest module (formerly HDI).  Harley's position on this is pretty clear from this statement, dated 4-16-97: "That information is considered to be confidential. Although it may have been given out in the past, we have since taken a new position of protecting that information."


The Vaccum Operated Electrical Switch (VOES) is the trigger mechanism for all EVO Harley's using the factory V-Fire III solid-state ignition.  The VOES takes a vacuum reading from the intake and converts that message from the engine into an electrical signal that is sent to the ignition module.  That in turn, tells the module to crank up the advance proportionately. 

These two curves built into the module's microprocessor:

1)  The low-vaccum curve (hard running, wide open throttle) kicks in the "RETARD FUNCTION,
2)  and the high-vaccum curve (cruising, steady throttle) allows maximum advance. 

The module merely picks which curve to use based on an ON-or-OFF signal from the VOES.

Four different VOES modules are used on Harleys, with 3 of the 4 having different switch points based on vacuum levels required to open and close them.  For instance, 1984 FLTs were equipped with an A-curve module and a VOES that switched at 7.0 inches of mercury, a setting that was designed to cope with the heavy payloads and lower engine speeds a typical dresser has to deal with.  Later, the FLT began using a D-curve module, as do all Big Twins to 1995 (and a P-Curve from 1996-0n, it is this P-Curve that is the OEM Ignition Module that the 1999 FXR2 came with) and appears to EMPLOY a VOES module HD#26566-96 which seems to fall in line with a 4.0 inches of mercy switch. 


Color Code........SWITCH POINT................MODELS

NONE...............7.0 inches of mercury...........Early EVO FLT (1984)
RED..................5.5 inches of mercury...........Late EVO FLT
WHITE.............4.0 inches of mercury...........EVO FXR and XL
BLUE................4.0 inches of mercury...........EVO Softail

By swapping the VOES you can choose a module to TRIGGER the switch to tell the ignition module to run the "advance" map sooner or later than it is constructed to do.  For example choosing a VOES with a 4.00 inch or 5.5 inch mercury switch.

Last August I discovered that those 1993-1994 FXRP Model bikes that were running the E-Curve Ignition Modules HD# 32419-91A were also running the HD# 26566-91 VOES SWITCH, which references 4.0 inches of mercury.  For some reason the 1999 FXR2's, 1999 FXR3's, and 2000 FXR4's were provided with what appears to be a 4.0 inch mercy switch VOES module HD# 26566-96, it's the "96" part that is confusing since the FXR's were no longer being built after 1994 except for the 1995 FXRP version, so one might assume that for the 1999 FXR2's, 1999 FXR3's and 2000 FXR4's that perhaps HD pulled the VOES Switch part number from the softails being built at that time, it's hard to say or to guess, but the assumption is they ended up with a VOES Switch that has a 4.0 inch mercury switch.  While there is no clear cut answer to this, according to one HD dealer and a quick reference check through some tech guide information, all FXR's categorically were provided with switches that would be seen as working properly between 3.5 - 4.5 inches of Mercury.

The VOES lives in the V of the cylinders (with it's black ground wire running to one of the left side head bolts), generally close behind the carb and slightly above the intake manifold.  On the 1999 FXR2 it is attached to the engine mounting bracket which then has the VOES Bracket that secures the VOES.  Swapping a VOES out takes about 2 minutes without the tank in place and everything removed, but it is POSSIBLE to adjust the VOES that's on the bike, however the process isn't in the Service Manual. 

I have not done this but as the Author explains:
If you remove the VOES, you can adjust it by removing the plastic/wax plug that covers the adjusting screw.  WIth a good vacuum gauge and an ohmmeter you can "test" incrementally greater or lesser vacuum settings to see if that helps create the responsive behavior you want.  Simply put the vacuum to the VOES until the ohmmeter reads zero, check the amount of vacuum it takes to do that, and record the reading. 

The Author suggests a "non-sanctioned test for pinging/lagging and seems pretty simple, while it may be a bit brutal:

With a normal payload, get the bike to operating temperature, filled with the fuel of choice in the tank, and take off from a stand still in SECOND gear.  Yes, that TENDS to LUG the motor, BUT you'll know after a couple of attempts if the BEAST is easily able to do this or if it gives you fits when you try.  THIS "crude" test and a VOES adjustment may not make a "GIANT" difference, but it CAN HELP fine-tune the ignition.  Just be sure to re-seal the adjusting screw with silicone when you've got it the way you want it. 

Here is another quick read which attempts to explain the VOES as well:


This Author's explanation gives rise to some merits of looking at wanting to use a VOES with 5.5 inches of mercury instead of 4 inches of mercury with some engine performance modifications.

I tend to put less emphasis on the merits of whether a 1999 FXR2 which weighs in at 570 lbs and a 1998 RK which weighs in at 710 lbs really needs to be considered so extremely different when it comes to the discussion of cams or other intricacies associated with the engine builds, when you could put 140 lbs more weight on the FXR fairly quickly with a front fairing, side bags and touring pack or by carrying a passenger so I tend to classify them together....I tend to attribute more ideas about what the engine needs and will require to perform the way I am searching for it to perform.

As the author suggests:

The higher the number (a VOES Switch with 4.0 inches, 5.5 inches, 7.0 inches of mercury) the stronger the vacuum is sucking, and the longer the ignition stays retarded.

If you get intermittent pinging on acceleration, and if switching to better gas doesn't help, try recalibrating your VOES to retard the timing at a higher vacuum number before you start going crazy doing other, expensive, stuff.

Now the reason you're digging around in here is that you need to adjust it, right? Let's say you're putting it on a bigger motor or that you've been getting an ignition rattle when you accelerate. That calls for adjusting it to switch to advance at a higher level - make it a couple inches, say, 7" of Hg.

Last August, I discovered that the 1994 FLHTP (Touring Styled Police Bike) as well as all FLHT models were using the HD# 26555-94 VOES.  The same dealer as referenced above confirmed that the HD# 26555-94 VOES were used in the 94 FLHT bikes and that upon referencing the technical information it appears that this VOES is described as switching properly between 5.00inHg and 6.00inHg or 127-152 mm. Thus this would correlate to being a 5.5inHg switch.

Which more fully supports the idea that with an engine that has been modified to provide more volumetric efficiency beyond the levels of a stock engine it may stand to reason that one may not require as much advance as a stock engine thus "retarding" the ignition timing, and thus merits of a VOES Switch with a higher switch capability of say 5.5 inches of mercury before it begins to switch the ignition module to the "advance" map may perhaps assist one in finding a better fit for addressing their timing through the methodology of the VOES Vacuum Switch.  This slight delay might simply be a nice bump to allowing just a bit more retard on heavy acceleration if you are experiencing some slight pinging manifestations during hard acceleration.

"....Stock factory timing is 35* (the asterisk is for degrees) BTDC.  How much further advance do you want to go?..."

NOW as I am progressing through this, logically it appears that I may actually want less "advance" than more, i.e.: moving in the direction of "retarding" the timing since:

Because a typical stock engine is less efficient with it's burn the timing needs to be advanced, thus we find evo engines pretty much set up from the factory with the timing coming on at 35 degrees and because now my engine is now more efficient the timing does not need to come on as quickly thus we need to "retard" the timing from say 35 degrees to whatever, maybe 20 degrees for example.

I am wanting to delay the timing curve going into advance as the VOES reads it so it makes sense to consider running the Ignition Module HD# 32419-91A and I have a different VOES Switch HD# 26555-94



--- Quote from: FLTRI on Wednesday, June 27, 2012. 09:44:30 AM. ---
after loaded test riding in the hottest weather you expect to encounter...

load-test ride new timing set point...
Repeat the same change until you encounter pinging when load tested.

IF there is no improvement from advancing timing, try going the opposite direction (retarding) testing for power increase.
Careful with too much advance OR retard as damage can be done if run long enough too far either way.
--- End quote ---

Bob and AJ,

 :up:  :up:  :up:  (appreciate you guys and your patience)

Well, here I sit, I am only a few miles from the worst wild fire in CO history.....and it hasn't been much hotter than it is right now in the history of the state, basically it seems the entire state is burning I guess I am good to go on that right now....

It's been in the 100's and over 500 homes have burned up....

I am only making this complicated because I don't understand it, and I am willing to read about it to understand it....hopefully some of what I posted above provides further foundation for my next steps...

As you can tell I have settled on a ignition module in coordination with a VOES switch....that's been addressed, so now as far as "timing" goes I am back here at the Cam Position Sensor Plate, mumbling to myself.....


Once again, just to be clear, one hash mark equals what?  How much advance, 1 degree or is it something else?

And why every other hash marks half the length, does this mean anything or is it just the way it's done on the plate to make visual references easier? 

I have no problems having this done on a dyno.  Which one should come first, setting the cam position sensor cam plate which I am now assuming is the "timing" and then setting your carb or the other way around or does it matter?



By calculating the circumference of the cam plate and dividing by 360* I have   determined that each hash mark on the timing plate = 5* at the flywheel.

Leave the timing plate where it is and use the ignition module to set a curve that will advance the timing curve faster until it reaches 35* BTDC.  Some modules will lower the fully advance timing. 

Look at the chart for the Crane ignition (last page) and you can see how much sooner the timing advances as the rpms rise.

It took me a while to wrap my head around this.

The FXR & Softail are light bikes and don't need to pull the timing back as much when the throttle is suddenly opened.  Only the mounting brackets are different.  I use a VOES form a Softail on my shovel, the timing plate was timed with a light to 35* BTDC and the Crane ignition was set by Bob's method of select and ride.  I ended up with a setting of #9.

I'm also lazy and did not read all of your novel.  :hyst:

Just doing some reading over on TWIN CAM section, and a poster there is having issues with "pinging" with his carb twin cam. 

Here is a partial quote offered to him:

--- Quote from: HD/WRENCH on Wednesday, June 27, 2012. 09:32:04 AM. ---The engine will use what it needs.. back down the advance one and see if it goes away.. Timing is set last after your afr is dialed in.. If your afr is floating in the low 13 range.. pull some timing.. provided the rest of the set is correct there is no "set timing " scale......
--- End quote ---

What I am gleaning from this is that I too was curious WHICH ONE should be done first, obviously going with the CAM POSITION SENSOR in it's current place without rotating it would initially make sense just to get it to a tuner.....and then it seems that you would set your AFR and get the bike with the AFR "dialed" in then concentrate on the cam position sensor plate and setting the "advance" or the "retard"?

Would this be a proper way to progress.......

As I stated I am simply trying to wrap my mind around all of this so I have a working knowledge of understanding.

I would generally desire to get my bike set at the 13.1 area for AFR if possible, but that discussion is a bit easier for me to understand, as I said I am trying to figure out this ignition timing stuff.




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