here's a way to maybe help some of you guys to understand it.
at high vacuum which means no load part throttle the switch is on and WOT low vacuum the switch is off.
ok now when your setting your timing you ground the voes wire which would be switch on set the rpm to above 1500 rpm which means the max advance of 35 degrees is present at just off idle.
and when the voes wire is ungrounded it goes back to its normal curve which maxed out at 35 degrees at around 3500 rpm
do you see now it doesn't retard the timing to save the motor. it advances it to gain fuel mileage and make the epa happy.
so if you don't run a voes you will never have to worry about the timing being to far advanced

 

Good a time as any since we are talking about tuning.........

'97.... at times you refer to using something called a WEGO to tune your bike using AFRs. I think you also said you used the ports in your headers. Can you explain?

 

if you don't have one you need it
its a wide band AFR meter I have one on my bike I can see my AFR in real time while im riding


here is the one I have
http://www.daytona-sensors.com/wego3.html

 

Um, at that price maybe you can loan it to your cousin Tommy Boy. Right?
Lol,
Tom

 

I look at vacuum advance and the VOES system like D_gyver: It's not vacuum advance, it's lack of vacuum retard. Same as on a stock HD: It's no (or low) vacuum retard so that you can have a higher advance at partial throttle conditions. Higher advance is better for fuel economy, power, etc., but bad for blowing a hole in the top of your piston.

I've tuned a few motors: 4AGE 20 valve, 22R, 883 Sportster. Fuel only on the 883, fuel and spark on the other 2. No dyno time, but data logging and fiddling while driving (Seat of the Pants Dyno.) After you fiddle with fuel, you fiddle with spark, then fiddle with fuel, etc. Eventually, I get to a point where I'm changing things back to how they were and I leave it. I need to tune the Sporty a bit more. Runs great, but I think I can lean it out at cruise and get a little better MPG out of it. I use narrow band oxygen sensors because wide bands cost at least 2 bills. The Sporty doesn't have enough amps to run a wide band anyway. I use an unheated narrow band for that one.

 

Real time AFR monitoring is nice, I hear they work well. D, do you have a Dynatek ignition programming kit? If so I see that it has a VGA connector, can you use a vga to usb connector to a laptop and will it still work? I'm thinking of getting one to customize the preloaded curves from Dynatek...

 

Wow, didn't realize there were so many MIT nerds riding Harleys. All this tuning and timing and AFR's and lambda crap is way too involved for me. I just want to ride my motorcycle, not tinker and tweak and study and map and analyze the AFR at every RPM.
This crap may be fun for you all but for me it's sucking the fun out of the whole subject.
With so many **s h**es here... clearly I'm in the right place.
So let me show you what the inside of my cylinder looks like, I'm not sure, but to me it looks like there aren't too many miles on this since it was redone.

 

here's a better one, and one of the piston.

 

You would be correct.

BTW, AFR is extremely important on a hot rod motor such as yours... learn it or cry about it.

 

That's not going to be VGA. That's going to be Serial, and if I had to GUESS, I would GUESS RS232. Count the pins. I've seen those USB cables for tuning the Dynatec, etc. ignitions. I'm going to GUESS that they are a USB to RS232 converter, which you can buy for a few dollars from various outlets.