Tacho Problem (see video)

[akronos]

When I bought the bike had the problem that you see in the video even with the original instrumentation. I tried 3 (original) and they all had the same problem. I also bought another tacho (what you see in the video) but nothing.  I tried to follow the black/yellow cable that carries the signal from the right coil to the instrumentation but it looks perfect. What could I check?

 

https://www.youtube.com/watch?v=ppyvV-N3rrA&feature=youtu.be

[Gixer1460]

What bike, what ecu / cdi fitted? If std Suzuki, there is normally a dedicated tach output which is usually black/red or similar. Thinking outside the box - black/yellow is coil signal colour and tacho may actually be reading half speed so the fluttering could be the red line limiter - clutching at straws ! ! !

[akronos]

My bike it's a 1985 GS1150 . The signal cable are black yellow from what i have read on manual

Edited October 2, 2019 by akronos

[Captain Chaos]

54 minutes ago, akronos said:

 I tried to follow the black/yellow cable that carries the signal from the right coil to the instrumentation but it looks perfect.

it could be cracked internally. Try to connect a wire from the coil straight to the tacho, see if it works then.

And yes black/yellow is the correct wire according to my factory Suzuki manual. Later models have a black/red wire from the CDI for tacho signal.

Edited October 2, 2019 by Captain Chaos

[Dezza]

The black/yellow feed to the tacho tees into the feed from the CDI to the coils. If you carefully open up the loom you can see where it all goes. The first thing to check is the join, and while you are in there change the wire from the join to where the wire feeds the tacho as the conductor can corrode right down uder the insulation. New 1mm cable is only ~35p per metre.

Below is the relevant page from the Suzuki workshop manual that shows the wiring for the feed.

Edited October 2, 2019 by Dezza

[Gixer1460]

13 hours ago, Captain Chaos said:

And yes black/yellow is the correct wire according to my factory Suzuki manual. Later models have a black/red wire from the CDI for tacho signal.

Thank you for the clarification!

[leemillssd]

I’ve got the same problem on my 84 GS 1150ES I’m trying to figure out. This is helpful. Thanks!