Electrical ?

[country50]

Unsure what the problem is .While riding the bike it will just miss a beat then pick back up ,its a feel more than hear.Turn your head right and you will hear the miss of course.Seems to be only around 45 and under.No tack so don't know rpm but at 55 or better no problem.Same with lower gears just at certain speeds .Slower .Have Dina S but don't think that's problem.Could be wrong. Also its not constant .Any ideas?

[rbonner]

Country, this is a tough one to figure out.  The last time I got involved in exactly this scenario was a gal in our ABATE group on an 83 Sporty at Sturgis.  First she had a mess in the wiring.  Thats the first thing I would check around the coil etc.  Clean neat unspliced wires lead to a happy motorcycle.

Missing engines can be anything from carb jetting to semi plugged bleeds in the carb to electrical.

I'd pick one and attack it.  The Sporty had a bad coil.  Might be as simple as a plug wire.  If they are a little beat replace them.  a semi-fractured coil wire will miss at low RPM and fire OK at high RPM.  BUt it would also work at high RPM in lower gears.

Start it up and idle it and wiggle the wiring and plug wires, see what happens.  Check back.

BOB

[76shuvlinoff]

 When it comes to wiggling plug wires on electronic ignition it is wise keep your sense of humor.

Dyna 2Ki ignition, I was feeling around the front of my tank trying to locate a vibration noise once at about 50 mph.  I got vibrated alright.

hey there's one for the don't ask thread.

[neten-o]

Do check the earth on the battery ..Rich...I always carry a spare coil too..

[neten-o]

When it comes to wiggling plug wires on electronic ignition it is wise keep your sense of humor.

Dyna 2Ki ignition, I was feeling around the front of my tank trying to locate a vibration noise once at about 50 mph.  I got vibrated alright.

hey there's one for the don't ask thread.

A friend of mine whistled at two nuns once and got an immediate short through the handlebars ..

[MMOCGuy]

There are a number of things that can be causing your symptoms. It can be either electrical or carb related. As Bonner said, go after one or the other first and completely eliminate it as the culprit before going after the other.

I think you are on the right track attacking the ignition as the fist culprit. As was suggested, check all of the electrical connections that have anything to do with the ignition. My first inclination would be to suspect plug wires or the plugs themselves. Once you have eliminated that possibility, then next place I'd suspect is the coil. A cracked coil can be the cause of imtermittent issues that can drive one crazy trying to find. Also, make sure you have the correct coil for your ignition. You said you have a Dyna S ignition. They require the same coil as points (5 ohms). Many times, a cracked coil will be fine when cold but will expand with heat and cause intermittent misses. After that, check all of the related wires for good connections (No corrosion) and/or minor breaks in the conductors. The best way to do that is to wire a jumper in parallel with or in place of an existing wire and then ride the bike under the conditions where the problem manifests itself. Do this one wire at a time and, if the problem disappears, you know which wire is bad.

If the electrical/ignition all checks out OK, then I would start looking at carburetion issues.

Hope this helps.

NormS.

[easyricer]

The ignition switch is the first place I'd be looking for such a miss. The ignition switches, depending on the model you have (FX or FL) ,are easily replaced with new HD switches with only minor modifications. Shy away from aftermarket switches unless you can get one from a good trusted source. Next I would be looking at the wiring itself. Both FX and FL used those terminal blocks to hook the harnesses together. They corrode and limit voltage. Then if you still have the factory switches on the bars and you can kill your bike with the OFF/RUN switch, that little switch likes to corrode also.
As for cleaning terminal connections, go to RadioShack and buy their brand of contact cleaner. It is very expensive but it's the only one on the market that is proven to actually do as advertised.
EASY

[shov60]

  Has your bike had this miss a long time or is it just recently and does it do it at idle or only when your under 45mph? a worm points cam lobe will cause this.         j

[rbonner]

The ignition switch on my FXEF rebuild was shot.  The bike was running when it came apart but the switch didn't stand the test of time hanging in the frame.  The ignition part was very high resistence.  I bought one of these to replace it.

http://cgi.ebay.com/ebaymotors/Round-Key-Ignition-Switch-Harley-Sportster-FX-_W0QQcmdZViewItemQQhashZitem53e14a8bebQQitemZ360262044651QQptZMotorcyclesQ5fPartsQ5fAccessories

On my FXEF the key is behind the oil tank and between it and the fender.  I needed to reform the fender just slightly to add a little room for the larger switch.  The wires on the switch were long enough to shorten up to reach the electrics which are located on the front of the frnder with three Circuit Breakers on snap in mounts.

This switch allowed the lights off and lights on positions, which would be good with kicker bikes or if you like to save the battery before start which I do.

The round key is like the modern HD keys so you don't have to worry about bending over the original flat key; also since it is not an actual HD switch the key  is not stamped HD, which is good for me as the DYNA key and fob looks just like the FX key and fob except one says HD and one doesn't.

There's versions out there from different suppliers, the price varies, I got the one with the key plate Off - Ign - Lights, some don't have plates and are cheaper, there's even two wire ones ...  Just search Harley Ignition Switch.  I've been pleased for $22 bucks.

BOB

[hotham]

Had a problem like this on my FXR.  The primary wires {small wires] had come loose at the coil.  To look, everything looked fine.  A little tug and I realized the wire was loose inside the connector.  I soldered the wire to a new connector, problem gone!

[fzee]

Easyricer is on the right track.  Also, I would look at loose harness plugs, connections or shorted wires.