I have a 1998 Dyna wide glide (Evo) with a problem I’m trying to diagnose myself. The bike has about 69,000 miles on it. It seems at highway speeds there’s a slight ON and OFF loss of power like maybe it’s going to run out of gas or there’s something electrical that’s cutting off the full spark to the cylinder(s). With the miles I have on it it I worry because I use it for daily transportation. I’ve had the usual stator/voltage regulator replacement (5 yrs ago), plus the usual tires, spark plugs, batteries etc. replacements. It has a Pingel fuel valve and I know the carb is clean.

Any ideas to start??

 

Have you tried new plug wires, they will breakdown over time.

 

Agreed, if that don't help check the coil.

 

maybe the ignition sensor going bad ?

 

How long has this been going on? Longer than the last fill-up? Gonna assume so. Besides compression (we can assume it's fine, or at least not intermittent), you're looking at proper fuel/air mix, and suitable spark delivered at the right time. If you're confident your fuel quality is OK, a possible carb culprit subject to intermittency would be fuel flow/level...double check the filter, float, float needle & seat. I'd move to the electrical realm if these are all good.
Not sure about your ignition system, but I'd check connectors for corrosion/crud, then do plug wires, coil, and lastly whatever ignition control module your bike has. Good luck, and let us know what you find.

 

One thing I did that I didn’t consider is that last fall I swapped apehangers and ran the electrics through the handlebars. I had a helluva time doing it and just ran the wires without the outer wrapping -where they came out of the bottom by the risers, I wrapped them and tucked some of it back up into the bars. I figured that all the electrics worked so all was OK. Maybe I nicked a wire?

I also learned the hard way about the electonic vaccum fuel valve issue while trying to drain the fuel and take the tank off to get to the wiring harness in the frame. .. after everthing was done and the bike was back on the road, because I was getting this drop in power, I assumed I had damaged the fuel valve/delivery and THAT was causing the power drop. I ended up putting in a Pingel valve and blocking off the vacuum hoseas instructed.

I really never considered the wiring of the bars issue.. and it may not be. Is there a way to test the wires without pulling everything apart again? (I maxed out my skills and patience on that project and really don’t want to do it again if necessary)

The Ignition Sensor, coil, etc. are options I’d check if I could get some direction on how to do it.

My last resort is the HD dealership. But at 80$ an hour and so many options to troubleshoot....I can imagine it could be a fortune..and my dealer here in Maine doesn’t have the best reputation for service work.

Also, the battery has been retightened and there is no visible corrosion either, the plugs look great too.

I think I’ve covered everything this time. Hopefully this’ll be a challenge for somebody out there.

After over 20 yrs and 140+ thousand combined miles on the road on Harleys, I can just feel it isn’t right you know what I mean right?

Thanks

 

i had a simular problem on my 1998 dyna it felt like it was running out of fuel or the petcock was not keeping up with engine demands..it would stumble then if you gave it a secound or more it would catch up and be okay. i thought it was a petcock or filter problem but found it was my ign module. i was able to confirm it by ridding it hard and when it stumbled i shut of the handle bar switch and then quickly turned it back on.this only took a fraction of a secound and the normal amount of time needed for it to clear up was alot longer. the cycling of the switch cleared it up immediatly. from there i double checked the ignition pickup coil and sensro and wiring.i even rode the bike around for a day with a snapon modis strapped to the bars to watch the signature of the ign wave form on the occilascope hoping to catch a bad signal. will after it did the same thing and i reviewed the ignition pattern on the modis i never got a bad signal. iswapped out the module first rode it a couple weeks and now problems. Hope this helps

 

That sounds pretty interesting. I think it’s worth a try. The cost of a new ignition module and putting it in myself to try it out is still cheaper than taking it to a dealer. I already have installed Taylor plug wires and I have a brand new Dyna Coil I never got around to installing..... this’ll give me a good reason to tear into it all. I’ve swapped an ign. module on a ‘87 Sportster before (long wires under tank etc.).......I’m thinking the Dyna was designed to be done even simpler.

Thanks for the recommendation.

 

your rectifier would do the same thing as well and that is MUCH cheaper!

 

OK, I was hoping this would be easy..... I'll look in my Service manual about the rectifier too. I don't know where the darn thing is.... Thanks for your input too