I'm putting in an Ultima (aka Dyna 2Ki) single fire ignition. The previous owner installed a Dyna S dual fire without a VOES. It worked good, but with +- 11-1 comp I'm looking for something that I can program to be a little more octane friendly. Should I use a VOES or is it redundant with this ignition? If I should, where does it go? I don't see anywhere on the manifold to hook the vac line up to.

thanks
shovhd

 

The vacuum hose goes to the carburetor, here is a pretty good web page on the VOES and adjusting one. My guess is you would need to set yours up to the 7+hg or it will give you detonation problems because it will advance the timing too soon. If you decide to also add an indicator-wiring a 12 volt led indicator for the VOES it is better to wire it in series rather than the way he describes it on the web page about the VOES.

http://www.wildwestcycle.com/f_voes.html


The S&S IST ignition sounds ideal with a knock sensor that automatically adjusts the timing, but I don't know if it works on non S&S engines. I saw the installation notes and it mentions using a crank sensor to automatically adjust the timing. I have read guys that have them can even run 87 octane without detonation problems.



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With 11-1 compression unless you have a very, very long duration camshaft you will need a VOES in order to run enough advance without detonation. Set it at 7hg to start and go up more if you have detonation.

 

And seems I read in the instructions that Ultima recommends to NOT use a VOES (on their engines) but If you use the progamming cable/software you can do all kinds of neat stuff with most any VOES arrangement. The standard curves are pretty good too.

Here's the built-in curves that can be changed with the switches. Might help with your decision or whether to add one...

 

Thanks Pajoe, but where exactly does it go on an S&S Super E? I thought it would go on the manifold, but there is no place on mine to hook it up. No place I can see on the carb either except maybe the vent(?) line? Do I need to drill and tap my manifold? Or buy another one?

I do like the idea of a VOES and I have a 6hg one sitting here, but I just don't know where I'm going to get the vacuum from.

thanks
shovhd

 

You will have to drill and tap the manifold, or you could just drill it and J-B Weld a piece of tubing flush with the inside of the manifold so as not to hurt the flow tpp much (my personal favorite) just be sure to rough up the tubing so the J-B weld has something to purchase on. Set the VOES to 7hg. You didn't hear this from me, but with a VOES you can run a little more timing without a lot of pinging and the engine will run better. Also the 120 Ultimas respond well to a little more compressiom and a little head work.

 

Thanks, is there a particular spot on the manifold that would be the best for drilling? Could I go right at the back side opposite from the carb (easiest spot to get at)? I'm thinking of trying this without pulling the manifold. Shop vac sucking out the carb and grease on the drill bit. Should keep any filings from making it to the heads. I hope

 

I've thought about drilling and taping a manifold right where you suggest, using the shop vac on the other side too. When I converted the Sportster to EFI, I used a Buell manifold, and the vacuum take off for that is virtually underneath the throttle plate. There's no vacuum at all there most of the time. I have no idea what they were trying to achieve. I didn't think about it when I installed it. I mean, hey, that's where the factory put it, so I figgered it should be OK. Wrong. Anyway, I have no useable vacuum signal for my computer or fuel pressure regulator, so I had to dump the maps and go to Alpha-N tuning, which is based on throttle position and RPM only and not engine load from the vacuum (MAP). I thought seriously about capping that port and adding another at the back. Take the throttle body off and stick a shop vac down the intake and drill away. But the bike runs really well right now and I really don't want to have to start the fuel maps over from scratch, so I've left it alone.

 

I don't know much about this thing. But when my bike was in the shop last week to get new tires and brake pads, I asked the mechanic to spend some time going over things for me and one of the things he found was a broken wire on the VOES. So he fixed the connections, saying it would run better with the thing wired up properly.

However, I am now having a little trouble with opening the throttle at speed on anything that's even remotely uphill. I used to be able to give it throttle at anything between 2500 and 3000, and have it respond quickly and strongly. Some hills around here I used to be able to stay in 5th and even accelerate up them if I chose. Now it's kind of sluggish when I do the same thing. I noticed it big time yesterday when I was out for several hours two up cruising through the Berkshires. I don't expect to fly around on an Ultra as if it was a sportbike, but there was one hill yesterday that I struggled up at 45, after downshifting. Speed limit there is 45, and most vehicles are traveling at least 10 mph over that. I don't think my bike should be so weak as to be getting in the way.

I'm curious about how the VOES affects the behavior of the motor in these conditions. I thought the VOES was more for when the motor was at lower RPMs. I'm going to go back to the shop and talk to the mechanic about it, but wondered what kind of feedback I might get here. BTW, I've already done the free-breathing exhaust/intake, a Wood 6 cam, upgraded ignition etc. So the major liabilities of the stock motor have already been addressed.

 

Slim, I remember you had a Spyke ignition installed some time back. If it was setup when the wire was broken, that would explain a lot! And it may have been set for VOES retard mode or initially timed without the VOES working. Either way, it should do better overall with the wire fixed, but something isn't set right with the ignition module you''re running. It should be a "no-brainer" for you shop to straighten out.