1983 Honda 185S electrical question

[Tomcall]

I put a new headlight on my 83 185S and put in a 12v 25/25 bulb. Started er up and the light was nice and bright. with in seconds the high and low bean blew out. The manual says the headlight takes a 12v 45/45w bulb. I thought this would be safe being less W's. I know that these trikes with no battery moro differently but I'm bot sure which way to go. Does it matter if I use a halogen bulb?
thanks for any help.

[JustEnough]

The manual shows 25/25w, but since the stator output is unregulated, a burned out or missing 5w taillight bulb could cause the headlight bulb to burn out prematurely. Here is a source for cheap replacement bulbs:

http://www.napaonline.com/Catalog/Ca...349_0291664274

http://www.napaonline.com/Catalog/Ca...347_0291663872

http://www.napaonline.com/Catalog/Ca...348_0291663715

I have bought the 45w, but you may want to make sure the base type is right on the 25w incandescent or the 30w halogen. I would try the 25w for a while before trying the more expensive halogen. NAPA has the taillight bulbs, but they are expensive at about $2.50 each. Other places sell the same bulb for about $.50 each.

[kb0nly]

Hows your tail light?

The lights are AC powered directly from the stator output, without a good tail light and headlight bulb together the resistance across the coil drops and the output climbs, the higher voltage then pops out the bulb.

So make sure you have a good 45w headlight bulb, not a 25w as that will also allow the voltage to climb, and get a good 5w tail light bulb. Only other option is to add in a AC regulator.

[kb0nly]

The manual shows 25/25w, but since the stator output is unregulated, a burned out or missing 5w taillight bulb could cause the headlight bulb to burn out prematurely. Here is a source for cheap replacement bulbs:

http://www.napaonline.com/Catalog/Ca...349_0291664274

http://www.napaonline.com/Catalog/Ca...347_0291663872

I have bought the 45w, but you may want to make sure the base type is right on the 25w

Oddly the manual shows 25/25 for the bulb spec, but the wiring diagram shows a 45/45... I have always put a 45w bulb in these. I will have to go dig through my box of spare bulbs now, curious if the last one i replaced was 45w or 25w now.

[roostin atc]

I had the same thing happen to me on my 83. I found a chafed wire underneath the rear fender on the frame. After I fixed that I have had no issues with blowing headlights. Check your harness for bare wire.

[kb0nly]

I would think a chaffed wire shorting to ground would only dim the lights... That would just lower the voltage to the bulbs rather than make them blow out.

There is some decent priced AC regulators available, they only need two wires hooked up, one goes to ground and the other goes to one of the stator output wires. Its basically an adjustable shunt to ground to bleed off the excess voltage. The good ones are automatic with a set point that allows you to turn a small trim pot to set what you want the max voltage at when at full throttle, etc.

I have also seen guys add a ceramic resistor across the stator output so if one bulb blows the voltage can't climb enough to pop the other bulb, but that usually results in dim lights at idle.

[Tomcall]

Thanks for the feedback. If I understand, because there is no regulator the watts of the bulbs has to be high enough to handle to stator output, esp. at higher rpm's. The manual does say 25/25 and that is what I used. Sounds like I need to look at the tail light as it is probably blown now as well. I will try the 45w and see if that provides the balance needed.
With my atc 70's I just purchased 6v regulators that are supposed to be for bikes with no battery. Will Let you know what happens.

[dman10]

First time I did that with mine it did that too, I replaced the bulb again and it was fine. Never had any more problems.

[kb0nly]

Thanks for the feedback. If I understand, because there is no regulator the watts of the bulbs has to be high enough to handle to stator output, esp. at higher rpm's. The manual does say 25/25 and that is what I used. Sounds like I need to look at the tail light as it is probably blown now as well. I will try the 45w and see if that provides the balance needed.
With my atc 70's I just purchased 6v regulators that are supposed to be for bikes with no battery. Will Let you know what happens.

Its not so much the watt's, but the higher wattage bulbs have a higher resistance, higher resistance to current flow and the voltage can't climb as high. But if you put a 45w in front and a 5w in the rear you should be fine. You can get a 12v AC regulator as well.

http://cgi.ebay.com/ws/eBayISAPI.dll...tchlink:top:en

Thats the Moose one that i usually use. Dennis Kirk has them also, sometimes the go on sale a few bucks cheaper there.

[Tomcall]

Well, I was trying to replace the head lamp with a new one and the 45w would not fit. so I figured the manual said 25/25 so I would be ok. Wrong!
I looked at the old headlamp and it says on it 12v 45/45w. By the way the tail light was also blown out. I'm putting the old headlamp back on with q new 12v 45/45w bulb. And I need to get a new 5w for the tail light.

[kb0nly]

Looking through my bulbs here i don't have any 25w, so i'm guessing i haven't come across one with a 25w in it yet. Whats odd, as i said before, if you look in the manual it shows the headlight bulb should be a 25w, but if you look at the wiring diagram it shows the headlight is a 45w. So maybe it was a change they made later, or who knows even a typo.

If you put new bulbs in and loose another one i would just wire in a AC regulator, cheaper than constantly buying bulbs.. LOL

[Tomcall]

Yes, I imagine a regulator would also be a way to address this and be able to use the bulbs I want?

[barnett468]

Hello tomcall;


The orig is a 12V 45/45W, $5.00, p/n 34901-hc3-003, 34901-323-750 and 34901-HB6-003.

http://www.partzilla.com/parts/detai...1-HB6-003.html

The manual shows 25/25w, but since the stator output is unregulated, a burned out or missing 5w taillight bulb could cause the headlight bulb to burn out prematurely.

This is because there is less resistance/load on the lighting coil correct?

The lights are AC powered directly from the stator output, without a good tail light and headlight bulb together the resistance across the coil drops and the output climbs, the higher voltage then pops out the bulb.

This matches what JustEnough said.

So make sure you have a good 45w headlight bulb, not a 25w as that will also allow the voltage to climb, and get a good 5w tail light bulb.

Ok, this is confusing to me. The lower the bulb wattge the higher it’s resistance. A 12v 25w bulb has around 5.76 ohms of resistance, a 12v 45 watt bulb has around 3.2. If the voltage output of the stator increases the lower the resistance is of the bulbs, then the 25w should lower the stator voltage output more than the 45watt bulb.

If this is the case, his 25 watt bulb would have more than compensated for not having a tail lite bulb and therefore should not have blown out if his tail lite bulb was bad or missing since the orig head lite bulb was a 45 watt.



PS – Cheap Chinese bulbs might be more likely to blow out than high quality ones.

[barnett468]

Yes, I imagine a regulator would also be a way to address this and be able to use the bulbs I want?

Just curious are you wanting to run a dim bulb like the 25w?

If so I think you can just toss it in there.

It might be helpful if you measure the actual voltage output of the lighting coil with and without bulbs off and on.

[kb0nly]

Yep, the regulator would fix all the problems with over-voltage blowing them.