Would retarding the timing a bit make things better???had the same problem with the same cam. Thied different things. What worked for me was lowering the idle speed to about 700. Dont ask me why, but after that no more bucking and kicking below 1500 rpm with little or no throttle.very smooth ride now

 

I've adjusted the timing for best results. I don't like my idle too far below900 rpm. I like my main bearings to last a while. From the research I've done, a performance cam will create a little more vacuum whick puts the VOES right on the edge of on/off/on/off. etc. I'm just going to put in a 5" VOES.

 

What would a 5 voes do compared with the one you have, what things will change in order for the bike to run smoother?

 

The OEM voes was set at 3 in. Hg, I believed that it kicked in (turned on) as soon as I opened the throttle to accelerate. That worked fine for the OEM cam. My EV13 performance cam will slightly increase vacuum at idle which puts the voes right on the edge of turning on/off/on/off etc. while at idle and lower RPM's. I believe that's why the motor is 'surging' because the voes is turning on and off continually. I adjusted the voes up to 4 in. Hg (that's all the adjustment I can get). It' still surges slightly. So my thinking is that if i step it up to 5 in. Hg that would put it right back were it's suppose to be and only turn on when I twist the throttle to accelerate.

If my understanding of how the voes works is correct, this should solve my problem.

 

Look At the Daytona Twin Tec Voes, they say 7" but i tested mine at just over 5"

 

hers's another thread on the yea or neigh subject
https://www.hdforums.com/forum/evo-c...r-no-voes.html

 

If you have the timing set properly, I would think your problem is carb related. My understanding of the VOES is that in certain high vacuum situations it retards the timing a couple of degrees. That's it, so if you where getting knocking/pre ignition when under full throttle for example, on an engine that the timing is set properly, then maybe I would suspect the VOES. I can't see how that would cause your issue unless you had a vacuum leak going to the VOES. That small vacuum hose from the intake to the VOES is easily displaced.

Based on your symptoms the area you are having trouble with is in the pilot jet area, either with mixture screw or too lean/rich pilot jet. From idle to about 1/4 throttle, the pilot jet and mixture screw provide fuel for the engine. Ignition related stuff is normally a definite miss and surging is carb related.

I'm not totally familiar with Harley Ignition's, so I could be way off base here, but when one thinks about a switch that operates with vacuum, it is either on or off. A couple of inches of vacuum difference going to the VOES is insignificant. I think I've read that the VOES when active retards the timing a couple of degrees, so if your max advance is 35 degrees it pulls it back to 33 or so. In the area you are having your problems, the VOES is not even playing a role. So my understanding of vacuum on an engine is that cruising down the highway, not accelerating, your vacuum would say be in the area of 15-20 inches, when you nail the throttle and as the engine is reving up the vacuum drops to almost zero in some cases and then as the engine gains more rpms, the vacuum starts climbing back up. So I would think it would actually be better to have a VOES that works at the lower vacuum setting rather than the higher one. If it is coming into play earlier then it is going to affect top end performance. In reality the difference between 3 and 5 inches of vacuum is pretty hard to get even with a hand vacuum pump. Again maybe I'm overthinking this one, but I'm just posting my thoughts. Something to add to the VOES conversation.

 

Read this two or three times:

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

The VOES is not your problem. I suspect a carb issue of vacume leak.

Yes you can adjust the VOES. Based on my mods, my voes is currently adjusted (by me) to be at 6.5 in/mercury and stock for my Dyna was 4.0.

I use an indicator light wired into the VOES circuit to tell me when my curve is in "advance". It is damn near always in the advance curve from idle all the way up UNTILL I go wide open throttle, then it retards.

Even the factory setting of the stock VOES is in advance mode even at idle. It is kind of a difficult to understand vacuum ratings. It is sort like the opposite of the normal thought process when dealing with pressures.

Need to edit for a better explanation: the bike usually runs in the advance curve "most of the time".

When I ride "spirited" and crack the throttle more than my usual normal riding, the VOES is adjusted to respond to that vacuum drop (less vacuum). This drop opens the switch (open means no more continuity. Another way to describe it: the switch is off. When no more continuity (off) you are in the lower or retarded curve.

I tuned my VOES to behave this way to avoid unnecessary pinging in certain circumstances. It is tuned to my riding style. When just cruising, it has higher vacuum and switches to "advanced curve" for economy.

 

I went ahead and installed the 5 in.Hg voes I ordered and it seams to have done the trick. Put 200 miles on her over the last 2 days and no surging. I'm very happy with how good she's running. I did triple check for vacuum leaks multiple times since I got the bike and rebuilt the carb.

Today I rode the bike to my appointment. Stopped for gas and when I started her back up I got a completely different surging. Only when the clutch is engaged and the bike moving. Goes away when I accelerate or decelerate. Symptoms point to the compensator. Will write a new thread when I get around to it, after doing some more investigating.