well my bike started popping through the carb a little the other day. took it apart and cleaned everything, really it looked pretty good. put it back together and bike started right up and idled really great, and low, but still had the missing/popping when id take off from a stop, come to find out the vacuum line to the voes came off. put a new hose on it and back to normal, that includes that i have to let my bike warm up a lot more before it will idle and i cant idle it as low. from what i understand the voes works like a vacuum advance on a car, give it gas and vacuum falls and the timing changes, vacuum and it advances. ive been told that i could do with out it but i needed to ground the white wire, from my understanding that would be like advancing the timing. just wonder why my bike will idle right away and idle lower with the voes disconnected, if i ground the wire then it starts, warm up for a minute or two then even ride for a mile before the idle will stabilize to a good idle, but still not as low than with out the voes. yeah i know this is a long thread but ive always tried to figure why it works this way.

 

I would not ground the VOES wire if you remove the VOES, but would tape it up to keep it on the lower curve. Depending on the advance curve you are using; with the VOES wire NOT grounded your timing may reach full advance between 2500 and 3000 rpms , whereas with the wire grounded your timing will be at full advance at about 1500 rpms. Having the timing at full advance all the time can cause detonation problems. My engines always idle slower when the timing was not being fully advanced (no VOES), I had my 80" where it would idle down to 500 rpms, they said it was not good to let them idle that slow, but it was kinda neat. If you want to disable the VOES, also plug the vacuum line at the carb so you don't risk another vacuum leak there. The VOES does absolutely nothing once you hit that magical 2500-3000 rpms (once again,depending on the curve) as the timing will be at full advance regardless, it only makes a difference at lower rpms when there is no load on the engine. You can unhook the wire from the ground, tape it up and plug the vacuum port at the carb and adjust your idle to where you want it. Removing the VOES will not hurt the engine nor will it hurt your maximum hp/torque on the dyno, it may make it feel a little less responsive at low rpms, and may affect your gas mileage.


on edit: if you have a vacuum controlled petcock, you need to keep the vacuum line going from the carb to the petcock, I don't know what years had them but my old '90 did not.

 

thats the answer i was looking for. so when the voes gets vacuum its grounding the wire, right? i like the fact that it will idle so consistent at a low idle, and yes i know its not good to idle it at 500 rpm. thats the only thing i noticed with it hooked back up a little more responsive. ill have to mess around with it and see what feels good.

 

Yes, High Vacuum = input grounded, hope this .jpg shows up ok as it shows it very well. The image is from a programable Ultima ignition manual similar to the Dyna ignition.The most aggressive "curve 1" is for 80" - 96" engines whereas the least aggressive "curve 4" is for 120" -140" engines.

 

thanks. ill try it without the voes connected and vacuum plugged to see if i notice a big enough difference in response to keep it or leave it disconnected. sure like the stable idle without it.

 

For a long time, I had a switch mounted beside the choke **** that I could use to disable the ground wire to the VOES, effectively "removing" it from the equation. It was nice in slow/stalled traffic on a hot day when spark knock at low RPMs was a problem or if I wanted it to idle slower for whatever reason.

The chart pajoe posted is good to show the curves and differences for VOES and non-VOES but the lines are not accurate.

On a Dyna2ki/Ultima ignition module, curve #2 does not retard either mode below 35 degrees. Total advance for 1 or 2 is still 35 degrees. Curve 2 only causes the non-VOES curve to reach full advance at a higher RPM. You have to use #3 or #4 to reduce the total advance... Curve 3 makes it 32 degrees and curve 4 makes it 30 degrees total advance. (Learned that the hard way)

 

ok. well i tried it without the voes and dont like it. motor runs better with it hooked up. seems the only advantage was being able to set the idle really low and i guess if i really wanted to spend some time adjusting my carb i could get it there with it hooked up. but its fine with the voes the way it is, and consistent. by the way the laughlin run is going strong, great weather today, have to get back out there and ride.

 

If you don't want a voes an alternative on the older blockheads was to replace the ign module with a shovel ign module which has a fixed advance curve, the timing is fully advanced at just over 1900 rpm. I ran one on my 87 flhtc for 3 years until I put a big bore stroker kit into the motor then I had to revert to a screaming eagle module which uses a voes to get rid of spark knock due to the sidwinders high compression 10:1 , I've had no problems with this setup which I'm still running to this day, this is an alternative to not using a voes on older block heads.

 

good to know. right now, everything connected and working, it running great. well today will be the last big day for laughlin bike week so i have to get out there and ride.