kz1000p electric tachometer issue

For Christmas my mom got me a kz1000 police gauge cluster (wow!) and I swapped over them onto my kz1000 csr but I've been having issues with the electric tachometer. 

When i turn on the ignition the tach will sometimes bounce a little from 0 and works pretty well until about 4k rpm. Above that, it starts bouncing all over like it has a loose connection or something.

I thought it was the splice into the black wire so I redid it and checked if there was any resistance in the wire; there was none. I also resoldered some of the parts on the circuit boards in case there was a broken joint.

I did not test the coils to see if that made a difference. I cant find any way to find the issue so here I am!

the electronic units have components that do not age well. Specifically, the electrolytic capacitors. They contribute to smoothing the ripple/noise in the ignition system. I replaced these capacitors in mine, and have had no issue.

Thanks! I'll look into that more and purchase new capacitors once I find out what the specific details of the capacitors are, unless anyone knows ahead of time what they are  .

I do not know the specs of that unit. 
Or if it compares to the tach in the KZ700. 
you can look at the circuit board and get the specs off them. 
You will want to record rated voltage, capacitance, rated temperature, and physical can size.
when Replacing them, take care. They are very polarity sensitive. 

It doesn't look like I'll be fixing my tachometer...  
Don't worry to much about me, I'm alive and well, besides a couple broken bones. 

If I feel motivated I may post the capacitor sizes, considering that I have all of this unfounded downtime. 

Well that sucks, hope you mend quickly 

Well i got bored today so I found the capacitor sizes. 

C4) L=13mm Dia=10mm 6.3V 470uF +105C
C6) L=11.5mm dia=6.5mm 25V 47uF +105C
C2) L=7.5mm dia=4mm 50V 2.2uF +85C
   

So I replaced the whole instrument cluster and guess what? Yep, that's right. The newer tachometer has a similar problem! I rode my bike tonight and at 55mph i was at 4300 rpm so thought I was in 4th gear but then I sped up and my rpm dropped to 3600rpm!!! There are issues in the 6k rpm range where the gauge needle will fluctuate. Geez I'll never catch a break. Does anyone have recommendations or advice when replacing these capacitors? I know they are polar but is the white part on the circuit boards positive or negative?

As a rule for sane people, circuit boards and electrolytic capacitors are always marked on the negative side. 

So i finally got the capacitors in the mail today and decided to take a crack at it! in the process of putting the new capacitors in i though that i bought the wrong capacitor 😱 however, it looks like it uses a different capacitor than the other tachometer i pulled the capacitors off of (old one on left and new one on right).  I looked it up and apparently the voltage difference shouldn't affect anything???? Therefore I decided to just go for it and use the 25V capacitor instead of the 16V. I put it all back together now so we'll see how it works! OLD  VS NEW (FYI there was a .22uF 35V tantalum capacitor that I also replaced but never mentioned)

Very curious about how this works out for you. There’s a potentiometer for adjustment on there. But I don’t recommend adjusting it without some kind of reference. I used a small battery powered oscilloscope to measure the frequency of the ignition coil inputs while I was adjusting mine. 

Actually, with a little searching, I found an app. It uses the sound pulses from the exhaust, the number of cylinders, and 2 stroke vs 4 stroke. 

I’ve not tried it. But maybe worth a try?

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