Plate light keeps burning out :(

[Corsara]

Every time I disconnect the battery, I later notice the plate light has burned. What's up with that? I'm tired of financing the plate light industry!

 

[David Thompson]

check your battery voltage when engine is running at various rpm's. high voltage can pop bulbs.

 

[RJ2112]

Every time I disconnect the battery, I later notice the plate light has burned. What's up with that? I'm tired of financing the plate light industry!

You really need to have a multi-meter, to figure this out.

The bulb has to have 12V or so applied to light, and a return to the battery to complete the circuit. If the bulb lights as it should, and blows out when you disconnect the battery, I have to think there is another lighting circuit that is dumping current to ground through the tail light bulb.

That other circuit was probably added to the bike. I would suggest disconnecting whatever electrical mods have been done and see if the tail light element survives battery disconnection.

 

[Motogiro]

Every time I disconnect the battery, I later notice the plate light has burned. What's up with that? I'm tired of financing the plate light industry!

Does the tail light burn out? It's on the same circuit.

Some lamps like the OEM tail lamp on the FZ6 have a physical bridge on the lamp filament. Although the lamp looks just like a standard 1157 dual filament lamp it is not. If you replace the tail lamp with the standard 1157 lamp it will probably fail sooner than the OEM lamp because it is inferior to the mechanically advanced OEM tail lamp.

I'm wondering if this might be the same case with your blowing lamp. Could it be a special design as with the tail lamp?

If you had enough high voltage spike on that lamp circuit for the needed time to make that lamp blow multiple times you're going to have damage else where. My first instinct would be to suspect bad lamps and confirm with some measurements. The replacement lamps might be 6 volt lamps and packaged as 12 volt. Incandescent lamps are pretty impervious to spikes It's a metal winding and if a high voltage spike present for a few nano seconds shouldn't phase it.
You might even go to a dealer if you can't get a specific quality replacement.
As with all marketing it seems to be okay to say something is what it isn't and is you do get the wrong part and try to follow up on where the problem is there are no one large enough to take responsibility.
My bet ... the lamps you're using...

 

[TownsendsFJR1300]

I know the 07 and up uses a separate bulb (much smaller- just push in) and don't use the 1157 style for the tag light (5 watts).

The Yamaha rear taillight/running replacement bulb does have the bridge in the center and is a bit brighter than an 1157 (more expensive too).

 

[Motogiro]

I know the 07 and up uses a separate bulb (much smaller- just push in) and don't use the 1157 style for the tag light (5 watts).

The Yamaha rear taillight/running replacement bulb does have the bridge in the center and is a bit brighter than an 1157 (more expensive too).

I remember my 06 had a separate lamp and assembly for the plate light.

 

[Corsara]

Hi everyone,

I'm the OP, thanks for the numerous replies (for some reason I didn't get notification there are posts, usually I do!).

So, I recently installed a sequential LED taillight, but the plate bulb burning was noticed even before, with the regular taillight that had no mods whatsoever on the rear. It's really confusing, but I should probably follow some of the advice you've given me (voltmeter measurements, etc.) and see where the problem lies.

Hope I get around to doing so soon, will write if I find the problem!