Tail light bulb

[posplayr]

So if I recall properly

Park Battery = 12.5V Brake Light = 12.5V
ON Battery = 12.0V Brake Light = 10.5V

What this is telling you is that:

a.) you have essentially no voltage drop in your wiring to the brake lights for the brake light load (that is because there is no voltage difference between Battery and Brakelight in Park alone.

b.) you have a significant load in ON, enough to pull the battery down 0.5 volts (headlamps and ignition) but is about normal as I have seen similar but usu sally not any lower.

c.) You have a lot of voltage drop (1.5V = 12.0-10.5) in your ignition switch in the ON position. Is you were pulling about 5 amps that means you have 0.3 ohms in the ignition switch. The corrosion is probably going to keep growing and get worse.

If it has taken 27 years to get this far, I guess it might last a little longer though

[MacGyver]

Pull out your ignition switch and clean it up. MG Chemicals Nu-Trol works wonders. The load from other sources when "ON" is likely the other part of the dim equation.

[Rocketman]

Excellent analysis guys. And assuming I keep this bike forever, and don't want problems to get worse, are the steps to remove the ignition and get to the contacts fairly simple? Again, assuming what I am cleaning are actually the contact points directly under the ignition switch.

Thanks again,

me

[chef1366]

Spray some WD-40 in there.

[posplayr]

Spray some WD-40 in there.

WD 40 will not eat the corrosion that is there. You need to strip that first with the etching material then lube it up.

The electrical contacts are in a little round module screwed to the bottom of the ignition switch.

[Rocketman]

I found some photos of an ignition switch on Ebay, and am wondering where exactly I'm supposed to clean, as it appears to be a sealed unit. Is inside the green 4-prong connector the place you suspect the corrosion is or inside the barrel where the key goes?

[posplayr]

the contacts are in the round part opposite the key hole. The switches I have from 83 ED / 81 EX are removable and probably would swap if that one doesnt come apart.

[Rocketman]

So I guess I'll pull this thing out soon, see how much of it can be diassembled, and what I can get at in there. If it doesn't come apart at all, I see no harm in spraying some electrical contact cleaner into the key hole, and using the key to mix it aroound a bit. Then maybe lube it with some WD-40 afterwards. Again, this is nothing that critical, just maintenance that should be taken care of before it gets worse, I guess.

[Steve]

Spraying anything into the keyhole will not get it down to the contacts that need to be cleaned. As posplayr said, look at the round part where the wires come out. On some models, there are screws that hold that part to the keyswitch assembly, on others there is a clip to be removed. Either way, take off that cap, you will see the contacts inside.

.

[posplayr]

I would use sometype of etching material; even a little navel jelly that you let sit in there a while and then wash clean and then spray with WD-40

It won't hurt plastic, and brass just gets spiffy clean. It won't hurt the chrome either.

[Rocketman]

I'm on it. Thanks guys for all the advice. Can't get to it right now, as a 3 day ride is planned starting this Friday early. But once its done, I'll update.

[posplayr]

use your ohm meter to measure resistance before and after cleaning on both ON and PARK contacts.

[Rocketman]

As long as I can open it up and access the contacts, it will be done.

[posplayr]

As long as I can open it up and access the contacts, it will be done.

contacts are measured at the connector at each key position; so there is no need to open for that.

if you can get any access through a crack you can get some acid in there to etch the contacts.

Metal prep by Por-15 is mild but is very liquid; you just immerse the entire switch. Ideally the lock will be off.

[chef1366]

But now it will turn real nice like!