Electrical gernius reqired

[PaulD]

As I'm a complete electrickery luddite it doesn't take much to stump me
Now I've finally got the bike running the way it's supposed to I'm going to sort the less important but annoying issues out. Number one on my list is the lazy rev counter, it never reads over 4000rpm no matter what, it ticks over at an indicated 1000rpm and blipping the throttle hardly moves the needle.
So is my tacho goosed or can anyone throw any light on the subject.
Please bear in mind that electrickery really is a black art to me

[fossie]

Not an uncommon fault, requires the capacitor/ resistor thingies checking / changing.
So a bit specialist

[Uncle Bob]

Looking at the electronic rev counter has been on my list of things to do for about 4 years now as all my Kats play up! I got a 750 popup rev counter for testing, bought an PC USB based oscilloscope to check signals and from the old circuit board drew up a circuit diagram. Unfortunately that is where it ended due to time on other things! The 750 popup at least has a proprietary chip on it, so that cannot just be replaced off the shelf if that has gone. Once I have the input waveforms and work out the output voltages it's a simple question of designing a Frequency to Voltage converter

I might get the time one day (plus it was about 25 years ago when I was in electronics before moving to IT).

Saying that, years ago I found a website where someone had the same issue with an 1100 Katana rev counter and they had a nice take apart and explanation of the fix which in the back of my mind was just a higher wattage resistor replaced. I'll take a pic of the popup circuit and highlight it. I have never managed to find that web page since. It'll be something that is common as things get older so probably worth trying to sort.

[PaulD]

Thanks guys

[pop-up]

Paul, I had a similar problem with mine which could be worth having a look at first. Turned out that a spider had taken up residence and its Web was messing with the needle action. Blow out with compressed air and all was good although said arachnid was a bit put out.

[PaulD]

Paul, I had a similar problem with mine which could be worth having a look at first. Turned out that a spider had taken up residence and its Web was messing with the needle action. Blow out with compressed air and all was good although said arachnid was a bit put out.

Thanks I’ll have a look and see if incy wincy is squatting in there

[johnr]

dont blow compressed air through the tacho assembly, tak it apart so you can see the works and clan it with electrical contact cleaner first, removes all the dust and crud but doesnt do any damage, though keep it off the clock face.

[pop-up]

Wasn't suggesting sticking an airline up it. just a gentle blowover. My clockcover unscrews so I can stand back to do it.