Greetings folks. I have 1999 Night Train that was a MESS when I bought it (chassis, electrical, engine, all of it but I got it for a good price and love to tinker). This is the first Harley I have owned in 40 years of riding and it has more soul than any bike I have ever rode or owned!

I have fixed a ton of the previous owners' (PO's) "work" and am trying to put the last ones to bed.

Bike is EVO 80 with Keihin CV 40. The bike was crazy-rich across the rpm band and only got about 30 mpg. It appears that some of the carb work by PO must have included hogging out the marked 42 pilot, as the plugs were fluffy black and idle speed was increasing as I turned in the mixture screw all the way to seated!

I have the carb jetting set now with a new 45 pilot and 180 main (was a 185, possibly hogged out too). Needle must not be stock as it is grooved (understand that the stock needle was NOT grooved). I have it clipped in the fourth groove from the top (so why was a .060 shim under it with the clip in third from top position?!?!?).

Anyway, I found the VOES engages with exactly 2.5 in/vacuum (all I've read says for a light weight bike it should be 4, a heavy bagger 6 to 7).

High flow pipes and filter. The vacuum at idle on the carb nipple pulses from about 0 to 15 in.

When "all is good" the warmed up scooter comes to a stop and idles well initially, but after 10 to 15 seconds the VOES must drop out and it goes to way-too-slow chug-chug, chug chug idle and will eventually die.

It is possible the one of the POs drilled out the air hole on the back side of the slide.

Any wisdom as to what I should do? Mod the VOES so it changes at 3 or 4 inches and adjust the chug-chug idle?

Thanks in advance.

tobascofred

 

Wheres your mixture screw at??? try it at 2 out and go from there.....what kind of a slide?? plastic or alum?? if its plastic it shouldnt have had any additional drilling.....do a search on mods....

 

After doing full adjustment the mixture screw is right at 2 turns out. Slide is aluminum. I didn't measure it, but the hole looked larger than pictures I have viewed on-line of the stock slide.

 

so your saying it will run and its driveable but after a warm up she will die out at idle, so no driveability issues only idle.....will it idle with the enrichner pulled at any amount?? wind screw out to 2 1/2.....swing petcock over to rez....take her out for a spin, if u got air cleaner off, make sure the slide is not hangin up.......have you taken the carb off???.....is the carb/mani gasket good and...no air leaks.......

 

Possibly Intake seals. During a low idle it's drawing more air from the leaks than through the carb and slowly dies. Because it's been messed with, it's been off and on the bike and quite possibly caused damage to the seals.

Blackened plugs often occur when one uses the choke to overcome the leak. But any re-jetting from the stock factory, and the swapping out of the primary needle valve sounds like an attempt to make it go faster. Most do this when putting in a different cam, or pipes. Some try to reset it up and don't have the experience so it gets really whacked out.

Let's hope it not lifter / valve issues.

 

Set up the VOES to engage at 7mm HG. Check the diaphragm in the carb to ensure that it has no holes or tears and is installed (evenly around the edge) correctly. Then replace the manifold seals as a matter of course as so much else is cobbed and look at the vacuum hoses Lastly get yourself an '88 Sporty needle and that should straighten pretty much everything out unless he has the timing off. Hope this helps.
John

 

Check or replace the accelerator pump diaphram for a pin hole leak , they will do strange things before an actual fuel leak develops. Your voes should be ok at standard 2.5 inches/vac. if i remember correctly . Check voes wiring as secure etc.
0-15 vac. at idle and fluffy carbon ? Po might have installed a lumpy cam .?
Hard to determine etc. considering Pos. previous work .?
Would go for carb. rebuild first .

 

2.5 is way too low for the VOES. The stock settings are around 6, depending on the year and model of the bike. You need to set it higher so that when you get on the throttle it will retard the timing sooner preventing detonation. Whoever set it at 2.5 obviously didn't know how it operated. The idle speed on your bike should be around 950 RPM's, lots of people set it lower and have a number of problems. Hope this helps.
John

 

I used a 7/64 drill bit on my slide. Nightrider recommends 1/8 but others recommended the 7/64. So you can go by that to check hole size in slide. While your in there check your spring and make sure it hasn't been messed with either. That change not done properly can really throw a cv off. I'd also check for any leaks in the vacuum pod in the top of the carb. The rubber umbrella with your vacuum issues. The search for the voes mod so you can readjust it.

 

If I set the idle to low on my 99 Softail Custom, it will drop out the VOES also, but it won't die. It just idles slower. At a very slow idle there is not enough vacuum to keep the VOES switched on.