Changing Speedo/Tach bulbs on a 77D?

[XS650D]

Picked up a used speedo and Tach as mine were going wacko and the replacement unit works great!
Problem is I need to change the bulbs as there very dim on speedo and not working at all in Tach.
For a 1977 standard does anyone know what the procedure is. Also what size bulb do I replace with and is there an LED replacement .I installed an LED on my tail light and it has worked great! No more blown bulbs.
I must have gone thru a dozen!! Thx for any advise.

 

[MaxPete]

To change the bulbs:

• Disconnect the applicable tach/speedo cable at the instrument (undo the knurled threaded collar);
• Gently remove the instrument Drive cable from the underside of the instrument;
• Remove the two small chrome acorn nuts on the underside of the instrument;
• Gently lift the instrument up out of its case;
• The bulbs are in little holders held in by their rubber shrouds (two per instrument).

...and yes, there are LED replacements available but I cannot recall the number.

I’m pretty sure that Forum member Danièl Black has used them - hopefully , he’ll recall it.

Pete

 

[XS650D]

Beautiful,Thx Pete!
Danielle out there?

 

[robinc]

I used these bulbs that I believe were the ones Daniel used. I think it was from his thread that I got this idea and part number.

What I found though as they draw so much less, they would trigger the RLU, making it think a bulb was burnt out.
My brake light was on dimly all the time, and got brighter when brake was applied. My headlight warning indicator would stay on.

Interesting that installing a LED bulb in your taillight hasn't caused any side effects. Did you track down the reason why your tailight blew a dozen bulbs?

So I am using one of these LED bulbs in my Neutral lights, and I think in my turn signal indicators. They sure are nice 'n' bright.

 

[5twins]

You may need to open the headlight and unplug the little harnesses running to each instrument. I don't think you can pull the units out of their nacelles enough if you don't.

Switching to an L.E.D. tail light bulb on my '78 triggered the brake warning light on the dash. I simply took the bulb out, lol. My RLU has been bypassed for many years so I didn't have to deal with that.

As you can see in Robin's link, the bulb base type is a BA9S. Do an eBay search for "BA9S bulbs" and a ton will come up. This bulb style was used in the Standards up to '79. All the Specials use a different style, the T10 push-in wedge type, which is even cheaper for some reason .....

https://www.ebay.com/itm/20X-T10-W5...White-Amber-/151247262283?hash=item23370a124b

 

[XS650D]

I removed my RLU last season, never did figure out why the rear tail bulb would blow but
since changing to LED its been good. I think it was related to vibration, was always the running light burning out.
Checked grounds and they seemed good but its been good all season now. I tried a LED headlight
bulb but the draw was not enough and it screwed up the draw on the system and the REG would read over 15 volts, went back
to standard bulb and now never gets over 14.4 volts. I may try again but run the front indicators as daytime running lights
to offset the draw, just might work!. Thx for the info Guys. I found a BA9S LED (1156 Series) on Line and will order a few to
try.

 

[XS650D]

Hey Robin, that EBAY ad on LED bulbs .Is 1 order equal 20 bulbs, Seems really low cost or have I got it wrong

 

[5twins]

Yes, you get 20 bulbs, pretty much a lifetime supply, lol. I had to replace several in my bike that were burned out when I got it. That was about 12 years ago and they're still good. I used spare (used) originals though. I have yet to test the longevity on these China bulbs.

 

[XS650D]

Interesting 5T. U have given me a thought!! I still have my old Gages. Im sure some of the bulbs still work.
I decided to pull all the bulbs out of my old gages and maybe I have enough good ones to replace the 2 burned out units in the New
(used) Tach I have. My New (used) Speedo appears to have all bulbs working so really only need 2. Might get lucky!!

 

[5twins]

If your "new" instruments included the bulb sockets and their wiring, you now have extra sockets you can make a nice little test light out of. I use mine for static timing and bulb testing mostly.

 

[XS650D]

Thx 5T. That was my next thought on how to test the bulbs, beautiful.