Bobbing Tach on XJ550

I noticed that my tach needle will 'bob' up and down while accelerating(i.e. its not a steady increase/decrease like it should be). If i'm staying at a constant speed its pretty steady until I touch the throttle. Would this be caused by something in the tach or the cable?

 

Could be the cable has loosened off. Make sure it is tight at the engine and the tach. If it is tight, look into getting it lubricated up and see if it improves.

 

yeah make sure it is tight and lubricated. I actually lost my tach pulling into the driveway today. Came to find out that the thing unscrewed itself and popped out of the engine. Glad it happened when I was home. It is pretty boogered up, so it doesn't really hold well. I may have to spring for a new cable and cap. The cap that screws the cable to the engine piece is what let go.

hope it is something simple for ya.

 

Pull the cable if you know how.

Remove the inside Cable from Outside sheath if yours does.
Clean the Inside Cable off with Carb Cleaner and Paper Towel until there NOTHING making a stain on the Paper Towel.

Hang the Outside Sheath Vertical
Flush it out with Carb Cleaner
When all the nasty shidt* comes out of there ... flush it CLEAN.

Oil it.
Put oil in it until it starts coming out of the bottom as fst as it is going in.
Lift the Bottom end and let the oil get all in everywhere.

Oil the Cable
Put 'er back in.
Put 'er back on the bike.
Test.

If the Tach still misbehaves.
Open the Instrument Panel

Oil this spot on the Tack
(See Photo)

 

Thanks!!

 

I had this problem when mine was coming loose, tightened it up and it fixed the problem.