Bouncing tachometer…………. Bong-Bong-Bong

[europe50]

Hey guys,
My 1986 Fj1200 has a tachometer issue. The tachs sits at zero, but when I start the bike it quickly bounces between zero-1000 RPM, even when driving it. The bike is all stock- no aftermarket or accessories.
Sorry to ask such a general question, but is there anywhere to start testing to quickly determine if the tach is bad? If so, can it be fixed reasonably?

Thanks!
Dean

[Varget22]

I now your pain. These instrument clusters are getting old. First does it just sit at 1k rpms reguardless of engine speed or are you talking just at idle? If it never goes above 1k then you either have a bad ground or the tach is buggered. From what I can see on mine (86 FJ1200) most of the wear comes from the constant vibration that wears the body of the mechanism oblong where the pivot shaft goes through. I think that makes sense. You know, where the pin that the needle mounts to goes through the body of the guage. It just getts loose after many hours of vibration. This may not be the case in your guage but I can see it in mine. Try to be a little more specific as to what the needle is doing. 

[europe50]

Hey Chris,
My tach just sits at zero when the bikes not on. When I start it, it bounces from zero to 1k, but not in a pattern, just kindof randomly (Because idle is higher than 1k). I don't know if this makes it more clear? I have it apart right now so I can't shoot video and post it to Youtube to show you.