Reserve Lighting System (RLU) function

[jetmechmarty]

I was trying to find out how the system functions on this and other old Yamahas. I finally gave up and looked in the manual.

Particularly, I was interested in this.

In a nutshell it does a bit more than what you can do with your left thumb. I went back as far as XS650E. I can't speak to earlier.

For those who may not have any idea what I'm going on about.

 

[Niels B]

Funny you put this up - I was trying to figure out the purpose too when I did the last XSE - wasn’t sure if I should cancel it or keep it. I end up keeping it as it was less thinking about how to omit than just let it be. I found the same info in the manual for the XSE - but exactly how the internal function in the unit function I never figured out - neither have I been able to find a diagram that tells me what’s inside the unit. Maybe I’ll take one apart some day and see if I can figure it out

 

[Jim]

Most folk just delete the RLU. I kinda like it. Every spring wakeup I'll disconnect low beam power to test it.
With low beam disconnected, you should get the white warning light and Hi beam comes on at low power.
Hell, long as it keeps passing that test, I'll leave it in and connected.

 

[Niels B]

Most folk just delete the RLU. I kinda like it. Every spring wakeup I'll disconnect low beam power to test it.
With low beam disconnected, you should get the white warning light and Hi beam comes on at low power.
Hell, long as it keeps passing that test, I'll leave it in and connected.

Never occurred to me to test it like that - but I’ll do so as well from now on

 

[jetmechmarty]

Most folk just delete the RLU. I kinda like it. Every spring wakeup I'll disconnect low beam power to test it.
With low beam disconnected, you should get the white warning light and Hi beam comes on at low power.
Hell, long as it keeps passing that test, I'll leave it in and connected.

Where are you disconnecting the low beam voltage?

 

[Jim]

In the headlight bucket.

 

[jetmechmarty]

On which model did the Reserve Lighting System (RLU) first appear?

 

[Wagner73]

I think '77 XS650D.

 

[jetmechmarty]

I think '77 XS650D.

I just looked at the wiring diagrams in the Tech section. The 1977 XS650D has the RLU shown. The 1976 model does not. With this clarification I’m good with putting this to bed, at least until someone decides to open up an RLU for analysis.
The Reserve Lighting System begins with the 1977 model.

 

[Wagner73]

As others have opined, I think the RLU can serve a useful purpose; the only caveat being that if you convert to an LED headlight, the RLU will decide the low beam is out and illuminate the high beam and the instrument warning light constantly as a matter of course, as it is setup to sense the electrical signature of an incandescent bulb (higher impedance, higher current draw) rather than an LED.

 

[jetmechmarty]

As others have opined, I think the RLU can serve a useful purpose; the only caveat being that if you convert to an LED headlight, the RLU will decide the low beam is out and illuminate the high beam and the instrument warning light constantly as a matter of course, as it is setup to sense the electrical signature of an incandescent bulb (higher impedance, higher current draw) rather than an LED.

Absolutely! An LED headlight requires bypass of the RLU. I found the RLU addressed in a tech article in MOTORCYCLE CLASSICS. The author stated “Engineers love it. Riders hate it.” He went on with troubleshooting and deactivating a broken unit.
As I said, the one and only time I needed it, I was glad to have it. That was on my XS1100 with an H4 lamp. I don’t believe I’ve yet suffered a Koito sealed beam failure. Also, the RLU has never been a nuisance to me. I’ll leave it be.

 

[gggGary]

My experience, headlight bulbs are more reliable than the RLU LOL.
Any bike I ride very often gets an LED headlight and a RLY delete.
Even ordered a 6volt LED headlight fer da baby beemer.
`Cuz the old guy riding at night behind that feeble 6 volt candle glow ain't happen'n.

 

[jetmechmarty]

My experience, headlight bulbs are more reliable than the RLU LOL.
Any bike I ride very often gets an LED headlight and a RLY delete.
Even ordered a 6volt LED headlight fer da baby beemer.
`Cuz the old guy riding at night behind that feeble 6 volt candle glow ain't happen'n.

I have a good bit of lust for this light on an XS motorcycle.
https://revivalcycles.com/collections/revival-sig/products/secret-led

 

[Wagner73]

I have a good bit of lust for this light on an XS motorcycle.

Go for it! I feel like once you try an LED, there really is no turning back!

 

[gggGary]

I have a good bit of lust for this light on an XS motorcycle.
https://revivalcycles.com/collections/revival-sig/products/secret-led

View attachment 371951

Being of "Scottish heritage" I use a 7" H4 headlight shell and an H4 LED, all in less than $50 and you can't tell from stock till the headlight is on.

 

[Wagner73]

Being of Scottish heritage I use a 7" H4 headlight shell and an H4 LED, all in less than $50 and you can't tell from stock till the headlight is on.

Not Scottish, but I completely agree with this... Candlepower housing and H4 LED.