headlight rewiring with relay

William K Denton wkdenton at verizon.net
Thu Mar 13 19:11:06 PDT 2008

Pete / Julian,

Thanks for the replies.  Apparently, a little voltage drop goes a LONG way 
in reducing luminescence.  See below.

10.5V : 510 lumens
11.0V : 597 lumens
11.5V : 695 lumens
12.0V : 803 lumens
12.5V : 923 lumens
12.8V : 1000 lumens (Rated output voltage)
13.0V : 1054 lumens
13.5V : 1198 lumens
14.0V : 1356 lumens (Rated life voltage)
14.5V : 1528 lumens

Anyway, I've been trying to do this "elegantly" by using one SPDT relay, but 
I've decided that it will just make things more complicated, not less.  So, 
I'm going to go the same route that Julian did by using two SPST relays 
tucked into the fairing next to the headlamp.

Bill in Yardley, PA
wkdenton at verizon.net

----- Original Message ----- 
From: "schnowz" <schnowz at localnet.com>

>  Bill, I added a relay,  but not to make the headlight brighter. I was too 
> lazy to do it right and simply used the headlight wire coming out of the 
> junction box as a signal (coil) wire for the new relay and then hooked the 
> contact side from the battery downstream in the wiring harness. This does 
> not take the load off the dimmer switch but it takes the load off the 
> ignition switch and the brown connector under the tank which are the 
> weakest points in the GPZ electrical system.
> B) As Julian said one of the existing headlight relays is so you don't 
> draw current from the battery for the headlight while cranking, so as to 
> give the starter the extra umphh. Older bikes simply did this with extra 
> contacts in the starter switch itself.
>  You're right about the misprint - the main schematic shows it as a 
> ignition fuse, which feeds the igniter among other things.
>  Pete Staniforth

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