2003 C10, 18k miles.  Just got the bike not long ago, so I am new here, but not on other forums for Bandits (old bike) and FZ1 (new bike). One night I was riding and my low beam went out.  High beam worked. So I ordered a bulb off Murph and went to put it in. It doesn't work AT ALL.  The hi beam indicator does correctly indicate the position of the hi beam switch.  Fuse is fine. I thought maybe it showed good and was bad, so I switched it with the identical 10A ignition fuse, no change.

FYI, bike starts and runs fine.  I was told that the headlight on this bike doesn't come on till it runs, which put me in a lurch because I had it apart doing the valves and installing blockoff plates and was waiting for stick coils, but I knew I really needed to chase this down so I remounted the coils and am feeding the gas via a remote tank.

WTF?

Thanks in advance.

The headlight should fire after touching the starter button, even for just an instant. The engine does not have to be running.

Now, do you have a head light harness bypass? If so, check any and all relays and connections. Put a test light or multi meter on the head light socket, keep going back in the circuit till you find juice.

OK, to start with, and make things easier, the engine doesn't have to be running for the headlight to work, but after turning on the key, the starter button has to be pressed and released.  Then there will (well, should) be electricity to the headlight.

I'd start by checking that there is voltage to the headlight socket.  If you have a multimeter or a test light, check this first.  If you have a multimeter, also check the ground at the headlight socket.  Also check the condition of the socket.  Folks sometimes put higher wattage bulbs in the headlight, which has a tendency to melt the socket - and check carefully, it may look OK, but the inside of it may be melted somewhat, causing a bad connections.

Also check the bulb itself.  It's possible to get a bad bulb.  Drove me crazy once on a car - high beam went out, bought and installed a new bulb - still no high beam - checked voltage (was good) - bought ANOTHER bulb - still bad.  Yep - got TWO bulbs with bad high beams in a row.    

Never mind, it's fixed.   

When the low beam went, I assumed it's a bulb and ordered a replacement, which I mounted and had NO light.   I chased down all the electrical and found I had power.  I dug the old bulb out of the trash and looked at it and NOTHING was broken.  Then I looked at the new Philips bulb I brought from Murph and it's broken in 2 places. I remounted the old bulb and now it's fine, high and low beam. Not sure why the low beam failed, but it's ok now.

Weird to have the low beam failure, then get a bad bulb. Talk about chasin my tail, sheesh.

Thanks for the replies, though.

Another thing I did wrong was look too far back in the circuit, wasting time.  I should have checked for power at the bulb connector and avoided all that backtracking.

On another note, I got this bike 3 weeks ago and I have done the following:

Oil change -  I asked PO when the oil was last changed. He said, "Last year, no wait maybe the year before. Actually I don't now".  I couldn't change it fast enough!
New Ultra Storm II front tire
EBC HH brakes on the front, speed bleeders and flushed the lines with new fluid
New pads for the rear on order
Block off plates
Valve adjusted (my mechanic friend's first stop after a 5000 mile bike trip was my house to help me, ok, shove me out of the way and do it. Good friend, eh?  He's being rewarded, trust me.
Air filter replaced. 
Washed and waxed, everywhere, even under the hood.
New rear tire tomorrow night.
Stick coils on order

Next up is cut down the stock "BuffetMaster 5000" POS windshield and replace the gear lube and grease the splines.

Low is not that uncommon to fail.  Most people do 90% of their riding during the day with the LOW beam on. It is the filament that gets used the most.  I drive mainly with my high beam in the day for this reason and safety.  Some folks dont like you to have your high beam on during the day but they really dont like meeting you on a dark highway with only your high beam

Nice list of repair/ maint. Seein's how it's apparently  not been  well maintained, I would go through the cooling system, your hoses, are probably 8-9 years old. Replace the cap(not sure of the car part number)  and the t-stat('82 Honda Accord). In fact, the coolant could be 8-9 years old. I'd hate to lose a day or more on the road over a $6 hose, and they are not easy to get at.

Also you didn't mention it specifically, but drain and flush the clutch line if you haven't. That stuff gets real nasty, real fast.

When you lube the splines, do both the hub and the driveshaft/final drive set. BTW, someone just reported recently that their hub splines went T.U. at 3x,xxx miles. Another case of non maintenance, I presume. Mine have 146,000 mi, and look good still.

Front fork oil and maybe/probably rear shock oil also. It really helps the rear shock to have fresh oil.

It's a shame it was neglected, some TLC should get it right and reliable.

It sounds like you're on top of things pretty good, just thought I would mention the above.

BTW, how were the valve settings?

Good Luck!

 
go steve go

Sometimes there is a bit of corrosion that can creep in there and simply removing and replacing the bulb can make it work again.

BTW, how were the valve settings?

Probably adjusted 3 or 4 of the 16, they were off maybe .001 or .002