Slow Tach Issue

[trinitysj]

my GS850 tach is almost nothing.. it moves more like the speedometer than a tach..

ie. idle moves to about 1000rpm.. but slowly. rev: moves a little but not at all showing what the rev was.. then slowly moves back to idle. When i drive it it moves up slowly but not to what i think it should be when i'm driving.

any ideas? I searched the forums and saw putting oil in the cable overnight. is that the best idea?

thanks

[BassCliff]

Hi,

It might just be time for a new cable. But first, lubricate the cable and also the mechanism inside the gauge. You can try turning the gauge upside down and squirting your favorite lubricant (WD-40, silicone, etc) in the input hole.

It's a little more difficult but you could also disassemble the unit and clean the magnetic assembly that drives the needle, similar to the "bell" assembly in the speedo picture below.



To gain entry, you may have to use a flat screwdriver and pliers to gently pry the bezel off.



One time my tach was flopping around because the connector end had come loose on the head side of the cable. I just screwed it back on with some locktite. Mind you, this was not the connection TO the head, just the connector on the head side of the tach cable.

Thank you for your indulgence,

BassCliff

[DanTheMan]

You may find that the end going into the cam cover has unscrewed or broken off of the cable core. If it's unscrewed, mix up some 5 min epoxy, clean the cable end and driver thoroughly, dip it in the epoxy and gently screw it back on (it goes on counter clockwise if I remember right, I've done this many times, but I can't remember for sure right now). Before putting it back in make sure it's well lubed. Also, put some blue loctite on the ferrule threads to prevent it from loosening up and losing the cable core on the road.

[trinitysj]

cool.. will do on both of those.. thanks

[Greg O]

Mine does that every year after sitting for the winter. But after 20 miles or so it works fine.

[north49]

slow tach issue

...I'd be 99% sure the lube inside your tach has turned, with age, to sticky grease. The only solution is to open the tach case and clean all the lubricant from the gear drives and especially around the front needle support. Clean it all very carefully with laquer thinner and re-assemble. Keep the thinner off the numbers or they will dissolve.
You might want to do the speedo as well, 'cause the same thing is about to happen there as well. The Japanese instrument lube turns to sticky grease after about 30 years.

[trinitysj]

...I'd be 99% sure the lube inside your tach has turned, with age, to sticky grease. The only solution is to open the tach case and clean all the lubricant from the gear drives and especially around the front needle support. Clean it all very carefully with laquer thinner and re-assemble. Keep the thinner off the numbers or they will dissolve.
You might want to do the speedo as well, 'cause the same thing is about to happen there as well. The Japanese instrument lube turns to sticky grease after about 30 years.

doing that tomorrow... did some prefab on my bike today.