Tail light bulb

[Guest]

Just need a quick favor. Have an '82 GS850L with stock tail light and stock 1034 (23/8w) bulb. I noticed that the bulb is dimmer when turned to the on/run position, as compared to much brighter when key is turned to far right position for parking light. Can anyone with a similar year bike please try this and let me know if the brightness is the same in the "on" position as in the "parking light" position, or if it is different. Either post here, or e-mail to Larry.Barasch@cbmoves.com

Thanks a million,

Larry

[posplayr]

the contact in the run position is likely dirtier than in park. The schematics would show a resistor if there was an intended drop in voltage to the light. You probably have a bad voltage drop to your coils indicated by harder starting if it is that noticeable.

[Rocketman]

No problem at all starting and both coils are brand new. Just noticed the difference in light intensity in the two different key positions. Could you check your light and see if it is the same.
Thanks.

[posplayr]

If you have an OEM ignition switch, I would suggest NOT putting it in park as I have had two OEM ignition switchs that are stuck (lock up) there.

2nd, if you re-read my post I said YOU have a difference in your ignition switch contact resistance. Measuring mine will not do any good.

[Rocketman]

I heard you loud and clear, and understand 100%. Thanks.

[posplayr]

Rocketman,
Voltage drops in either the ignition switch or the starter switch or both is the main reason for the coil relay modification. The contacts corrode and the resistance goes up, as resistance goes up the voltage will drop. Think of it as an early warning to do something.

If the light is less bright it is for only one reason the voltage is lower to the bulb. So why is the voltage less, look at your schematic it is highly unlikely that there are two sets of wire driving your tail lights.

OK BAD ON ME!

There are at least two reason for the voltage to drop.

a.) Poor contacts in the ignition switch

OR

b.) ON ignition load pulling the battery down. OK so this is a "feature" when you have a undercharged battery

Check your battery voltage when you go into park v.s. ON. If the battery voltage drops it is your battery not being able to supply the ignition load at the same voltage in ON as PARK.

Alternately, If you pull the ignition switch plug away from the harness , you should be able to measure the resistance directly to confirm this.

There is still no reason for me to test mine, as my battery and switch condition could yield either the same or different results.

You can answer all these questions by using a volt meter.


Jim

[chef1366]

The headlight comes on with the ignition in the "on" postition and doesn't in park hence the dimmer/brighter tail light.

[Rocketman]

Battery at posts initially measures 12.5 volts in parking light position; 12.0 volts in run position. I'm thinking the two different tail light intensities is most likely normal, and in 27 years of owning this bike, I've never really looked that closely back there to compare. Maybe I shouldn't have looked today. With any luck, I'll see another '82 850 on the road soon, and compare lights. Perhaps I'll deal with it then, if there's actually anything to deal with.

[posplayr]

Battery at posts initially measures 12.5 volts in parking light position; 12.0 volts in run position

Well it is normal for it to change; there is obviously a difference in loads. Ignition is one and headlamps as Bill says as well.

So basically you are doing a load test on your battery (assuming the ignition switch is OK).

Assuming you are at about 12.8-12.9V off then there are no issues.

The headlamp will also dim when the blinker is on when idling. Just artifacts of a finite supply.

[earlfor]

Just need a quick favor. Have an '82 GS850L with stock tail light and stock 1034 (23/8w) bulb. I noticed that the bulb is dimmer when turned to the on/run position, as compared to much brighter when key is turned to far right position for parking light. Can anyone with a similar year bike please try this and let me know if the brightness is the same in the "on" position as in the "parking light" position, or if it is different. Either post here, or e-mail to Larry.Barasch@cbmoves.com

Thanks a million,

Larry

The tail light being brighter in the park position than it is in the run position is normal. Ignition in run position charges the ignition system and powers lights. In park, only the tail light bulb receives power. If your battery is not fully charged, the difference will be more noticable.

Earl

[Rocketman]

Thanks very much. I concur. Just one of those things I failed to take notice of in the past quarter century.

[Steve]

Evidently the roads in your part of New York are too straight.

You need to go to West Virginia where they have LOTS of KMA turns.

What's a KMA turn?

Also known as KissMeAss turns, they are tight enough you can check your own tail lights.

.

[earlfor]

Thanks very much. I concur. Just one of those things I failed to take notice of in the past quarter century.

Heh heh heh You know you're getting old when you start noticing things for the first time after 25 years.

Earl

[Bruin]

I always wondered what the other key position was for.

[Rocketman]

Glad I could help.

P.S. Just for kicks, I measured the voltage at each pin inside the tail light bulb socket under three different scenarios:

Ignition in "Run" position (no brake applied): Left pin 10.5; Right Pin 0.4
Ignition in "Park" position: Left pin 12.5; Right Pin 0.0
Ignition in "Run" position with brake applied: Left pin 10.5; Right Pin 10.5