Hi friends, I’m back with a similar issue I’m troubleshooting a combination of electrical and idle issues on my 1995 Harley-Davidson FLSTN Heritage Softail Nostalgia (Evo 1340). The bike doesn’t have the clean “potato-potato” lope it should — idle sounds uneven, flat, and inconsistent. Manifold gaskets have recently been replaced, and the carb is clean and properly tuned, so vacuum leaks are unlikely.



Here’s what I’m dealing with:

• Idle lacks the classic Evo lope — rhythm is unstable or absent
• If I turn the idle screw up, the lope completely disappears and it idles like a sewing machine; it only starts loping if I drop the idle speed way down
• Timing feels off or stuck (???)
• VOES is original and untested
• Ignition module may be failing and not responding to VOES (???)
• ignition switch is physically loose — if the key shakes or I turn the bars full left, the dash lights and headlight cut out (but the engine keeps running)

I’m trying to determine:

1. Could a failing VOES or loose ignition switch be affecting power or ground to the ignition module, causing unstable idle or misfire?
2. Should I replace the stock ignition module with a factory-style unit (OEM #32410-94A or Daytona Twin Tec 1005), or go with a Dyna S + mechanical advance and eliminate VOES altogether?
3. Is it likely that there’s a pinched or frayed wire near the steering neck cutting power intermittently?

Here are some videos of the bike idling and acting up:

• https://youtu.be/5AkjsuDW3s8
• https://youtu.be/rZkhOYdEAB8
• https://youtu.be/owZs9eL9wiE

Any thoughts on diagnosis, wiring tips, or parts you recommend would be greatly appreciated. I’m after long-term reliability and that proper Evo idle.



Thanks in advance

 

EVO's don't have the "lope", potato potato idle.
You'd have to keep the idle too low, starving the engine of oil.
Others will disagree, it's your bike.

 

I agree with yoyu, I don't want to starve the engine of oil. However, I'm referring to a clean and strong lope, as opposed to this messed up tact what I'm hearing right now. If you listen to this video that was taken a year ago, there is a day and night difference. After many trips to various know-it-all mechanics, the bike is just getting worse...

 

Your idle is supposed to be set between 900-1000 rpm, the potato potato lope is when the idle is really set to low and is not going to be consistent

 

I can see what you mean the idle in the last video does sound much stronger, does the bike only have 8,000 miles on it like the speedometer says??, start at the basics, have you done a compression test on her? I did notice the light in the speedometer flickering when you gave it gas but that could be nothing

 

It looks like you have a CV carb, do you know how to adjust the idle mixture screw? The bike has been worked on so I'm sure the the plug/cap over it has been removed, here is some good info on adjustments http://www.cv-performance.com/instructions-guides/ ,

 

The flickering lights seems like it might have an electrical issue. Battery cables tight? Corrosion on the battery terminals? I would also check the cables themselves, they can corrode inside the insulation and cause issues like this.
I had an 02 Super Glide that was acting like what you describe, and it turned out to be the positive battery cable was broken inside the insulation.

 

Idle: As others have mentioned, 900 to 1000 rpm's for proper oiling means no lope.

Voes: test for vacuum leak using a mity vac or similar. The Voes diaphragm or the vacuum lines can leak as they age. The VOES triggers the advance curve at a certain setting in inches of mercury (in/hg). Also check the single wire coming out of the Voes. Trace it, check for damage or grounding out of the wire and check the connection (spade connector). Running a VOES is a good thing and the system works well, so IMO keep the VOES set up and use the Dynatek 2000i (see below) ignition.

Carb: Wish I had a dollar for every time some one said "carb is clean and adjusted correctly" only later to discover a carb issue... This is not a dig on you, but often times there is something that is simply overlooked, dirty, misadjusted, and owners or mechanics just don't realize it. Simple as that. So don't discount a remaining carb issue and it really needs to be part of the problem solving mix. Get rid of the extra inline fuel filter. You have one in the tank.

Ignition module: If your talking the black box under the seat, they rarely fail. It is there to provide you with an advance curve and a rev limiter. That's all it does. If your talking the cam sensor in the nose cone (or not), then it is worthwhile to pull the cover and inspect it. If original, they go bad and can melt the potting material in the electronics of the sensor. You will see the brown goo potting material can be oozing out (melting). I feel this oozing is a symptom of the electronic circuitry in the sensor failing and overheating, which causes the potting material to melt. The true sign of this sensor failing (other than the melting) is the bike runs good when cool, bad after warming up. Can sometimes cut down to one cylinder, run funny, or not run at all when warm (no spark or intermittent spark), but then after it cools it returns to normal or near normal. Rinse and repeat when it gets warm. That is the common symptom, but anything is possible if it's original. Replacement is a matter of taste but the Dynatek 2000i is a good one and popular here. It replaces the nose cone cam sensor and the "black box" ignition module all in one. Has selectable advance curves, can manually turn on and off the VOES, convert to single fire, is reliable, etc. It depends on what you want to spend. You can just replace the black box, or just replace the cam sensor or kill two birds with one stone with the Dynatek (or similar), up to you.

Ignition switch: When you say "it's loose" do you mean the mount or the actually guts of the switch are worn? Check wiring and repair if mount issues, tighten it back up. The switch itself does not need to be "grounded" but should be securely mounted after checking the wiring and connections to it. Ignition switches wear out and have been known to fail all together or intermittent. If the key is loose but the actual switch itself is secure, then yes, this could cause your lights issue.

Lights going out when moving steering: As above regarding the ignition switch, but, check wiring for a loose wire connection or a bad wire/ground. Gotta play detective and start tracing wires till you find the offending wire or connection. Might be more than one wiring issue going on at the same time.

Manifold seals: Careful installation is necessary. Just because the seals have been replaced does not mean they are leak free. It is easy to get misalignment to the manifold during install and and when reinstalling the carb. The seals can be temperamental. The manifold can move on you or you can get some uneven torque on the seals when installing the carb. The carb actually should be installed on the manifold with proper alignment to the carb backing plate to cylinder head mounting bolts BEFORE final torque of the intake manifold flange mount bolts. This can be a bit of a PITA but necessary. Carb and manifold needs to be properly aligned with regards to cylinder head and the carb backing late mounts.

The above is just my 2 cents. These bikes are old! Parts can and will fail and eventually wear out. Need to give the bike some love from time to time and expect some surprises along the way! All part of the deal when owning an older bike. Good luck

 

At the idle in the video, sounds like 600--8l00 rpm.
Lights will be yellow or flicker at too-low idle speed.
If idle is intermittent, my first guesses are spark plugs or wires, or the nose cone sensor.
Engine temp sensor will have some mighty strange symptoms if starting to fail.
No comment on carb work, as my 98 has MM.

 

Also, look into that ignition switch. Dash lights going out when turning is wiring, doing it when moving key is switch.
A lot of threads on ignition switch troubleshooting.