Mystery Component!

[Demorgan]

Hi! I just noticed this odd looking electrical component under the tank, just slightly behind the horn, behind the head.. it seems to have rattled itself loose and in fact after taking the pic the yellow-black wire just plain fell off.. however, I can't see easily what it attached to, it doesnt seem to be affecting the bike, but not really happy about leaving a is nor removing without knowing what it is.. I checked the manual and closest math I could find was an item called "relay" but not more useful info than that.. any ideas? It's a 1977d btw.. mostly standard.. ta!

 

[5twins]

I think that's a diode and it's part of the rear brake lining wear switch wiring. Some '77 wiring diagrams show it, some don't, because not all the '77 models had the lining wear switch. Only early '77 models had the switch, it was discontinued part way through the model year.

 

[Superjet]

On my old 77 I had before there was a rubber plug on the rear brake hub. My 83 doesnt have it. I wondered why, guess I know now. Thanks!

 

[5twins]

The rubber plug was for a visual inspection hole. That replaced the electric brake wear switch. But the visual inspection hole was pretty useless really. It's so black and dirty in there, you can't see shit, lol. Your '83 should have a wear pointer on the lever pivot shaft. Here's everything you ever wanted to know about the rear drum brake plates .....

http://www.xs650.com/threads/650-rear-drum-brake-plates.51046/

 

[Superjet]

Yup if I wanted to inspect the shoes I just took it all apart to take a look!

 

[Demorgan]

this is very interesting! thanks chaps! i do have the little rubber plugged hole on the drum, but there is def no wiring or anything else in there, so presumably this diode is redundant? Maybe the back wheel is of an earlier bike? in any case, is looks like that this component has dropped off isnt going to cause me to explode without warning..