Tachometer doesn't work at all

When i bought the bike the po said that the tach would work it just needed a pin. Does any one know where to start troubleshooting this?

Thnaks

 

The tachometer is mechanical, and cable operated. There is a drive gear that runs off the exhaust camshaft, it lives in a housing on the right front of the cylinder head. The cable runs from there to the instrument itself.

I have no idea what "pin" your PO was referring to.

In order of probability: Cable, instrument, drive gear.

Instrument tech: http://xjbikes.com/Forums/viewtopic/t=15303.html

550 Seca cluster disassembly: http://xjbikes.com/Forums/viewtopic/t=14948.html

Tach drive gear/housing & oil seals: http://xjbikes.com/Forums/viewtopic/t=19538.html

No pin anywhere that I know of. Start with the cable itself; disconnect at the instrument, lower it enough so that you can observe the inner cable, and start the motor. See if it turns. Go from there, it's a simple system.

 

Thanks for the reply fitz, your seca is absolutely perfect! You did a great job on it. those how to's r great

 

On my '82 750 Seca, the Tach is electrical (right?)
Anyway, it's flailing wildly over 4500 RPM at cruising speed (80+). Any clue as to what this may be?

 

Thank you. I try to pick up where the manuals leave off, or have crappy photos.
Which Seca? The black one or the white one, I'm proud of both of them for different reasons.

Yes, it's electrical. Which means you could have a flaky connection somewhere (go figure) OR the instrument itself could use a tiny spot of lube or two.

Obviously, my "how to" on Yammie's mechanical clocks doesn't cover it-- however, close examination of the instrument itself (once removed from your cluster) will reveal which points you might put a droplet of lube on/in.

I've got a couple of electronic tachs; take a look and you'll see what I mean.