Electrical speedometer issues

I've been through 4 speedo pickups and two meters during the past 3 or 4 years, and I still can't get the needle to quit jumping. The meter I got now is more or less brand new, and is working like it should. The pickup is clean and move freely and works like it should. Still, the needle jumps when closing in on 50 mph.

I was always convinced that the pickup or the meter was the problem until recently. I noticed that the needle jumps when accellerating or maintaining higher RPM (4,000 +) So I tried clutching when going downhill and the needle is steady and shows the correct speed. :blush: I'm sure it hasn't been like this the whole time though, as the jumping has changed between the different setups I've been through.

So my question for you electrical gurus is this: What is casuing the speedo interference? While it's naturally related to the charging system, what should I check first?

I have no other electrical issues. Charging system works like it should, and while I haven't checked lately, the output @ 3,500 rpm was 14.1 V when I tested it before taking the bike out for its first ride this spring.

Here's a link to the wiring diagram
kzrider.com/component/option,com_docman/...d/gid,260/Itemid,49/

are you sure its electrical? is it possible that the mount for the speedo has old tired rubber or foam thats been shall we say squashed for the lack of a better word? i once used a few washers to take up the slack from worn out mount foam on my 650 and it immidiately started doing exactly what youre describing. for the record the tachs will do the same. im not sure if this apllies to electric speedos but its worth a look...steve

I recently had a similar problem with the speedo on my ZN700. But the point where the needle would jump around wasn't at any particular speed and varied in intensity.

On my speedo, it was the bell shaped (magnet?) driven by the cable in the speedo itself that was causing the problems. It had some rough spots that looked almost like it had been ground down slightly or were casting marks, and I'm assuming that it caused interference in the magnetic field, which in turn caused the needle to jump around. It would give off an almost electric buzzing sound when the needle jumped, caused the tach needle to bounce slightly, and even blew out some of the dash lights due to the vibration.
Unfortunately before I could find out if there was a way to repair the root cause (the rough spots on the bell shaped magnet), the needle did a full 360*, broke off when it hit the "pin" at the 0 MPH point, and eventually sprung the entire needle outwards. Now it looks like a sprung clock from a childrens cartoon.


A NOS speedo for my ZN would cost me about $385USD....IF were still available.
To make matters worse, the part# for my speedo shows it only fitting the 84 and 85 ZN700 and no other bikes.
So now the search is on to locate a good used speedo.

Sorry to ramble on Stein, but I hope you have better luck than I'm having in fixing your problem.

fixer5000 wrote:

are you sure its electrical? is it possible that the mount for the speedo has old tired rubber or foam thats been shall we say squashed for the lack of a better word? i once used a few washers to take up the slack from worn out mount foam on my 650 and it immidiately started doing exactly what youre describing. for the record the tachs will do the same. im not sure if this apllies to electric speedos but its worth a look...steve

Thanks for the tip, Steve! I think you might actually be right about that. Went for a ride yesterday, and when touching the meter I could definately feel a stronger vibration on the speedo than the tach. Haven't had time to try and fix it yet, but from just taking a quick look, it seems like the meter has no vibration damping at all.

I'll take it off and see if I can mount it so that it doesn't vibrate som much.