I read a couple of posts about headlight bulbs blowing soon after installing a new replacement. Rapid filament burnout is caused by high resistance across connections or bad wiring. The bulb sometimes will tell you you have that problem. When you pull the blown bulb you'll see the glass coated internally with a white substance. That's a sure sign you have a high resistance connection between the regulator and the bulb base connector, which can also be bad. When you suspect you have this problem start by doing a resistance check by connecting a Volt/Ohm meter from the point where the wire is connected to the regulator output and the bulb connector. It should have almost no resistance and the meter should not fluctuate as you shake the wiring harness that's connected to that circuit. Most likely you'll find there is resistance showing on the meter. At that point you'll need to check every connection along that wire run. Unplug connectors and look for green copper tarnish. If you have it you'll need to clean it off or replace the connector. Check for soldered connections along the wire run inside the harness. Solder degrades over time. If you find any soldered connections you should cut them out and replace them with crimp type automotive connectors even if there not causing problems because they will later. You can't simply strip the wire, stick it in the connector, and crimp it. Buy Marine grade waterproof synthetic grease available at all auto parts retailers that's used to grease boat trailer hubs. It's also works great as a dielectric grease to prevent tarnish from developing in electrical connections. Coat the wire end with grease, insert it in the crimp type connector, and crimp it. It also works great in all bulb connectors instead of spending a fortune buying those little packets of dielectric bulb grease packets at the auto parts store. If you find the wire itself is coated in green when you strip it back a little you'll need to completely replace that wire in the wiring harness. Also check the high/low beam switch. You'll be surprised at the crap that finds it way inside that switch housing and could be causing your blown bulb problem. Clean it out, check and clean the contact points if you find green or coated in crap. Liberally apply marine grease to the switch and contacts before reinstalling it. I hope this helps!
Yep; used to be high quality (only we didn't really think of it as high-quality, it was just normal) copper wire never got tarnished internally. I started to notice it on Japanese imported cars and bikes from the 70s onwards, when they were a few years old. Just a guess, but I reckoned it was to do with the high proportion of recycled copper the Japanese auto / bike makers were using in their wiring. To get similar non-tarnishing quality we used to take for granted, we now have to specify marine grade wiring. It's not really all that expensive if you're only buying what you need at a time. It starts to mount up when you buy in reels of it, of course.
I recently tried an LED H4 replacement "Bulb." An "RTD" Motorcycle Headlight for Yamaha, Kawasaki ect.
It came from China to the mailbox for $25. I had considered the complete LED headlights a few years ago but they were expensive and I was not sure they would work properly with the automatic switch box for a burned
out H4 headlight filament. Thought it might try to switch back and forth thinking a filament was burned out.
This "RTD" device fit right into the Vetter Shell, was a direct replacement for the H4 Bulb.
Pros, It is very bright. Less current drain lets other bulbs like instruments shine brighter.
Cons, The big copper colored thing/"Bulb" is easily seen in the center of Your headlight.
Almost all of the light comes out of the top half of the reflector/shell.(needs a custom reflector)
There is a slight flicker at low RPM, probably the rotor magnet passing the stator coil makes a surge.
It is obviously not a standard bulb, anyone can see that. It does not say DOT on it that I can find.
Will probably go ahead and get a full headlight assembly like the "Trucker" now after seeing the LED worked.
Not sure what the LED Headlights will do on failure, company reps a few years ago indicated there was no
automatic switching to a spare light or filament on failure of an LED Headlight.