Headlight relay question

I'm planning to install a relay to have the headlight cut out while the starter is engaged as described by Bill Wilcox a while ago. I'm thinking of having the same setup for the taillights. Do I need two relays? I'm not an electrician but it seems like there would be a problem having both the headlight and taillights go through the same relay.

It may not be worth having a cut out for the taillights - LED bulbs may accomplish pretty much the same thing (i.e., less current draw while the starter is cranking) much more easily. Has anyone tried either of these?

I'd think if the relay contacts are rated for the current(AMPS),the relay should be able to turn on both headlight and tail light. Make sure you have enough contacts to be able to wire the headlight and tail light circuits as some have 4 contact and others 5.

Some relay information:
www.boardrelays.com/?gclid=CNzst_PAkZgCFRo-awodC2zVng
www.the12volt.com/relays/relays.asp
www.2carpros.com/how_to/how_do_i_check_a_relay.htm

Another thought: I have an 82 GPz1100 B2 model, I got tired of having the headlight circuit come on while starting the engine. Since my bike has the reserve lighting device(it's designed to turn on high beam at reduced voltage if low beam goes out)I bypassed it with a handlebar toggle switch.

So now when I start my bike,a low wattage bulb come on indicating headlight out in the instrument panel so a majority of the current goes to the starter motor, after my bike starts, I flip on the toggle switch and the headlight comes on with no loss of high or low beam circuits.

I used a Mil-Spec moisture resistant toggle switch # MS25307-232. It has 6 screw terminals on the bottom.

KYKZ1100 wrote:

I'm planning to install a relay to have the headlight cut out while the starter is engaged as described by Bill Wilcox a while ago. I'm thinking of having the same setup for the taillights. Do I need two relays? I'm not an electrician but it seems like there would be a problem having both the headlight and taillights go through the same relay.

It may not be worth having a cut out for the taillights - LED bulbs may accomplish pretty much the same thing (i.e., less current draw while the starter is cranking) much more easily. Has anyone tried either of these?

I did exactly that on my KZ750 and I used two 10A relays. On mine, all power (and ignition power) is fed in through the big 20A fuse and then after it there are two 10A fuses which serve:


1) The headlight and instrument lights

2) Tail, brake, running lights, horn etc

I put a relay on each power line coming from each 10A fuse, route the power through the NC (normally closed) contacts and use the 12V to the starter relay to power the two relay coils so they will open when the starter relay is energized.


BTW, I do run LED turn/tail/run lights to reduce power draw. Use the 3W Luxeons from superbrightleds.com, they are the only ones that are bright enough.

MFolks wrote:

I'd think if the relay contacts are rated for the current(AMPS),the relay should be able to turn on both headlight and tail light. Make sure you have enough contacts to be able to wire the headlight and tail light circuits as some have 4 contact and others 5.

Some relay information:
www.boardrelays.com/?gclid=CNzst_PAkZgCFRo-awodC2zVng
www.the12volt.com/relays/relays.asp
www.2carpros.com/how_to/how_do_i_check_a_relay.htm

If using one giant (like 25A) relay to cut off everything be sure to put it AFTER the power point feeding to the ignition but before it feeds the sub circuits which have smaller fuses.

Thanks. I already bought a relay - it's 40 amps. I wasn't thinking about the taillights when I bought it, but it will definitely handle both headlights and taillights as long as doing so doesn't cause some other problem.

I just ordered a pair of 4 watt Luxeons from SuperbrightLEDs after getting a number of cheaper ones from several places listed on ebay. I plan to use the Luxeons for the front turn signals and use the stock bulbs in the rear turn signals since they aren't on while starting the bike. I also replaced all the instrument lights with LEDs from Superbright, although I haven't actually ridden the bike since I put them in so I'm not sure how they'll work.

When I built my circuit I considered what power draw(s) I wanted to cut-off during electric starting.

I do a little local night riding so I asked myself what I wanted to turn OFF on the side of the highway on a moonless night. I decided that the last thing I wanted OFF was the Tail Light followed closely by the Instrument Lights. So that's the direction I took. But it's your bike and your call.

I like your idea of the LED Tail Light bulb:
- What brand and part number did you end up using?
- Was it a direct form-and-fit replacement?

Are your Instrument Lights LED's also?
- If so, what brand and part number did you use?
- Do you like the results?

Best of success,
Bill

PS
"One relay or two relays". Well it's your call. One relay is cheaper, faster to install and takes less place but there is more current drawn through the one relay. I guess it would come down to the current rating of the relay. On the other hand, two (or more) relays makes trouble shooting and fault isolation a little easier... maybe.

IMHO, also to be considered is:
It would be great if all relays were the same model (form-and-fit) so that only one on-bike spare relay would be necessary... now that's real practical.
Bill

bill_wilcox100 wrote:

I do a little local night riding so I asked myself what I wanted to turn OFF on the side of the highway on a moonless night. I decided that the last thing I wanted OFF was the Tail Light followed closely by the Instrument Lights. So that's the direction I took. But it's your bike and your call.

I like your idea of the LED Tail Light bulb:
- What brand and part number did you end up using?
- Was it a direct form-and-fit replacement?

Are your Instrument Lights LED's also?
- If so, what brand and part number did you use?
- Do you like the results?

I agree with you about the taillights and had not really thought that through. If I stall at an intersection at night and the engine takes a while to start, there would be no taillight.

I haven't ordered LEDs for the taillight yet, but I ordered the same bulbs that might work in the taillight in amber for the front turnsignals. If they are bright enough there, I will order some for the taillight.

I spent some time trying to figure out which LEDs would work for taillights, turnsignals and instrument lights. The ones I ordered for the front turnsignals are the 4 watt Luxeon bulbs at www.superbrightleds.com/cgi-bin/store/in...ecs%2F115x-x3X1W.htm . The normal 1157 bulbs in my taillights and front turn signals use about 8 watts on low and 27 on high, and produces 38 lumens low and about 400 high. The 4 watt Luxeons draw 25/155 ma and produce 35/140 lumens. They don't sound as bright but apparently are not directly comparable to incandescent bulbs in terms of lumens. A number of people say that there is less loss of light going through the red or amber lense than experienced with incandescents.

For the turn signal indicators and the neutral, oil and headlight out indicator lights, I got WLEDx4, wedge-base bulbs www.superbrightleds.com/cgi-bin/store/in...Fspecs%2FWLED-x4.htm . Because it seems these will be too bright at night, I just ordered one of these in blue www.superbrightleds.com/cgi-bin/store/in...2Fspecs%2FWLED-x.htm for the brights indicator.

Also, you can't use the stock flashers for LED turnsignals so I bought two of the Universal Motorcycle Flashers ($8.95 each) from the same place. They are two pin and fit in the same rubber holders that my old ones did.

I used BA9s-W-12V LED bulbs for the instrument illumination (4 bulbs - BA-9 bayonet base). If you search for those on SuperBrightLEDs page you'll see them on a list.

Again, I haven't been able to ride since I install these. I plan to post a lessons learned here once I'm done.

Sorry I haven't figured out how to hide URLs yet.

MFolks wrote:

Another thought: I have an 82 GPz1100 B2 model, I got tired of having the headlight circuit come on while starting the engine. Since my bike has the reserve lighting device(it's designed to turn on high beam at reduced voltage if low beam goes out)I bypassed it with a handlebar toggle switch.

So now when I start my bike,a low wattage bulb come on indicating headlight out in the instrument panel so a majority of the current goes to the starter motor, after my bike starts, I flip on the toggle switch and the headlight comes on with no loss of high or low beam circuits.

I used a Mil-Spec moisture resistant toggle switch # MS25307-232. It has 6 screw terminals on the bottom.

I have the reserve lighting device also, which according to the FSM causes the high beam to come on (although at lower power) when the low beam is burned out. It seems like if I put a relay on just the lead to the low beam, the reserve lighting device will defeat the purpose by having the high beam come on. Do I need two relays, one on the low beam lead and one on the high beam?

Like I mentioned earlier: I used a toggle switch so I can start the engine without the headlight coming on.

I used four wire colors: BLUE for the BLUE/ORANGE wire.
PINK for the BLUE/PINK wire.(This is one circuit
____________________________________________________________
YELLOW for the BLUE/YELLOW wire.(This is the other circuit)
BLACK for the BLUE/ORANGE wire.

So now when I turn the key on my bike,the headlight failure light comes on(a low watage light bulb), I start the engine, flip the toggle switch, and the headlight comes on.

I suppose a relay would do the same thing but would require some re-wiring of some circuits.

Thanks MFolks. I might go the switch route rather than the relay also. I can't see how to do the relay without doing two of them.

KYKZ1100 wrote:

Thanks MFolks. I might go the switch route rather than the relay also. I can't see how to do the relay without doing two of them.

There should be a main 12V line coming off the ignition switch going to a 20 or 25A fuse. The power for the ignition should tap off that line somewhere, you can put the relay right after that point so it cuts off everything except the ignition at starting crank.