Wonky tacho

[Mark Serj]

Hi all,
I had a reasonably stable tacho when I had Lumenition ignition, it would get a bit wobbly at the upper range when driven hard, but was quite useable. Now I have an Accuspark ignition it is only stable at fixed revs and is all over the place when driven hard.

Any suggestions (related) would be appreciated.

Cheers

Mark

[Mark Serj]

BTW it's a MK2

[LAMBRETTLAD]

I have the same system and a stable rev counter ,has a wire / connection been knocked etc?

[KOY 23]

Mk 2 Rev counters are usually fine with Luminition, the fact that yours wasn't and is useless with Accuspark, could point to the rev counter. Do you know somebody with a spare? Accuspark and the other cheap units are designed and build to a very low cost and appear not to drive the rev counter as well as the premium makes. If you know someone with a spare Pertronix/Aldon it may be worth trying that, as they have an excellent reputation.

[LAMBRETTLAD]

I've used Accuspark for the last dozen years on 5 or 6 different cars with no trouble whatsoever ,I've also fitted Luminition with no problems .
you pays your money and takes your choice ,and say as you find ,
good luck in finding your problem

[wilf]

A potentially simple fix is to put a capacitor between the tacho output of the ignition and earth. Often, the square wave nature of the tacho output is enough to upset an older tacho. All they need is a capacitor to "knock the edges off the squarewave" and they can be happy again. Any decent instrument reconditioner should be able to mod your tacho.

[Mark Serj]

Thanks Guys - good advice to get my head around.

Cheers

Mark