hello,
I have a 98' dyna fxd, I'm having a pretty annoying issue. The issue is that the bike starts, idles and runs fine when opening the throttle, but when I cruise it around, the speedometer shuts off completely and then goes to running off one cylinder. it will stay like this for about 7-10 seconds then go back to running fine for a bit. This problem has happened the past two times I have rode. Any help would be appreciated.

 

The speedometer or tachometer shuts off? (or both)?

Is the ignition stock or some part of it aftermarket?

 

both speedo and tach shut off and the ignition is stock

 

Try switching plug wires front to rear and see is the opposite cylinder drops out. If so, change the coil. Not common, but they can short out when heated and not blow a fuse or throw a breaker.

I'm not familiar with that late of a model Dyna and it's wiring, don't have a schematic. But I doubt it's a wiring short, otherwise it'd blow a fuse. I think the only breaker on that one is the main and everything else is fused. Could be simple as a corroded harness connector.

Otherwise, maybe some of the other guys with a wiring diagram or previous exact symptoms will happen along to help.

 

I will give it a shot, thanks.

 

'98 Evo has a dual fire ignition FWIW. I agree that if the tachometer shuts off, the coil might be suspect.

(Isn't the speedometer cable driven still on the '98's?)

 

speedometer is electronic. I tried switching plug wires at the coil and experienced the same symptom. This time since it was a little darker out, I noticed that when the intermittent issue came up again, all of my lights went really dim as well until it went back to normal.

 

Check your battery negative ground wires for tightness.

 

They went to electronic speedos in early-mid '90s, don't remember the exact year. Yes, all Evo's are dual fire as stock. OK. Must be a short pulling the voltage down causing a weak spark but not enough to pop a fuse. Probably on the "lights" circuit and the best place to start is in the headlight bucket, tail light and rear brake light switch. Just a start hunting thing looking for a chaffed wire... could be anywhere. Wish I could be more help. Good luck.

 

ground wires are clean and tight, do bad stators or voltage regulators produce symptoms like this?