Tach surgery question

[randy]

On the way home this weekend, my tach dropped to zero. It's intermittent, so I know it's electrical failure. How do the guts mount inside? If I remove the face bezel, is the mechanism mounted to the back of the face or to the inside of the shell?

Anybody got pictures of a disassembled tach? 78E model. Thanks.

Randy

[Dennyz]

The tach is driven by the alternator. When my tach died, it turned out to be the voltage regulator. You may not notice, but I bet your head light goes out at the same time.

It started out intermittent for me. While going down the road the tach would die and after a while come back. I could reach over the head light and see that it was off. When this happens, the charging system is shut down. It happened more on hot days and eventually failed completely.

[randy]

Thanks, Denny, but no, my headlight is OK. when I tap the tach the needle comes up, so I'm sure it's something loose inside the tach itself. Charging / running voltages are OK, too.

Just want to know what's inside and where before I rev up the dremel and slice her open.

Randy

[Renegade]

Before you start cutting open the tach, check the connections. My Special did the same thing, and the tach finally just quit. I had the tank off for a carb adjustment last week, and when I put the tank back on and fired her up, the tach worked again. Something just didn't make good contact, and wiggling the wiring harness around was enough to restore contact to the tach.

[xs1100yam]

Hi Randy,

I remember I open one long time ago (78 !) The only way to open the tach is to unset the black metallic part around the glass.
I can send you picture of an open one : PCB, dial, DC motor controling the needle, fuel gauge galvanometer. ( if you give me an E mail adress )

[prometheus578]

I agree with Denny and Renegade. My tach would go crazy and then die, but the lights never went out. (could see them dim at night, though) System seemed to be charging ok, too. Finally got tired of it and swapped the regulator and re wired the bad connection at the main fuse. All electrical probs ceased... headlight was really bright, and the bike stopped dying whenever I used the turn signals. (Try trouble shooting THAT one!)
But... if you'll be taking apart your tach, time for a little customizing. Cut out a photo of your wife, girlfriend or dog and glue it to the face of the tach before you put it back together. (I had the assembly apart to fix the fuel gauge. Seemed a good place for a skull) Seal the seam of the tach with permatex or something similar. Stay away from crazy glues... might fog the lens. Don't recall if it's plastic or glass.

[fxrer]

Randy,
I just posted a reply to beechfront, to his speedometer thread on 10-21, about how I got into my tachometer.

Should help you get inside, and investigate th problem.

[piet]

take it the easy way solving the problem
buy a donor xs1100 and swap all the parts you want to have and sell the donor bike as soon as your finished with swapping

[randy]

Those kinds of measures only result in the parts becoming rarer. I'd rather fix the part than create another XS-cadaver.

Randy