Tuesday, May 25, 2010

Science and the Art of Motorcycle Troubleshooting

To put it in scientific terms, I believe Mary Ann's Burgman 400 has been cursed by Satan. I have observed that in the rare situation when you really want to ride it, and none of our other modes of transportation will do, it won't go. Since we have a car and three other working motorcycles, plus bicycles, there are not many times when you really need the Burgman. But when Mary Ann has promised to give someone a scooter ride on a particularly nice day, the scooter has once failed to start, and once had a flat tire.

So last night we were about half way home from my mother's, the sun was setting, and suddenly Mary Ann pulled into a parking lot to ask me to check the headlights. Both low beams were dead, but the high beams were working. We decided to go the rest of the way on the high beams, and worry about the low beams tomorrow.

As we were riding along with the high beams alone, I was already starting to kick my mind into gear to fix the problem. Obviously, there was no way both low beams would burn out at exactly the same time, it had to be a short somewhere in the wiring harness. And since the Suzuki is covered with body panels, this was going to be a major job stripping the machine down to its frame and tracing the low beam wires from end to end to find the problem. I also considered trading the Burgman in on another scooter, and let somebody else pay for the repair.

The next morning, I was able to actually start the troubleshooting process, instead of imagining apocalyptic scenarios for the bike. Step one in the scientific process is now "Google". My first hit was the infamous "sticky starter button". Apparently, the starter button also contains a "headlight off" button, which when pressed will start the bike and turn off the headlights temporarily to save electricity for the starter. And this button sometimes sticks and the lights stay off. But because Mary Ann's high beams are working, that hypothesis is eliminated.

Second hypothesis: Burnt out fuse. The fuse is not hard to get to, although tools and one body panel are involved. I was surprised that the low beam fuse in the Burgman was 15A, while the spare fuse was 10A. They are supposed to be the other way round. Obviously a previous owner had tried pulling a little switcheroo on their own. Anyway, after testing with a multi-meter, and swapping fuses around, it was proven to not be the fuses either. Doomsday panic was fast setting in.

Third Hypothesis: Burned out headlight bulbs. This, of course, is impossible. How could both headlights burn out at the same time? After five years and 21,000 km, it seems like one in a million. Also, the bulbs are hard to get at. So I was contemplating dismantling the headlight dimmer switch next and looking for loose wires.

I found some instructions for changing headlight bulbs strictly by feel, as you cannot see what you are doing, but you can reach in. So I managed to get the bulb out and test it. It seemed to have no current flow on the low beam terminal. Because there are three wires, I had to find out by research that the black wire with the white stripe is ground, and the yellow is high beam, and the white is low beam. Also, I have a 12 volt electrical tester probe, and when I poked inside the socket, it lit up when I turned on the low beam. So apparently the one in a million chance actually happened. The headlights had burned out.

I went over to the Parts Source to see if I could find one of these unusual looking 35/35W HS1 bulbs, but they didn't have any. The parts guy was quite helpful, explaining how two low beams burn out at the same time. Apparently it happens a lot, not because they burn out together, but they burn out at nearly the same time (within a few months), and the owner does not notice the first one until both lights are gone and other drivers start flashing their lights at them.

Problem solved, so to summarize the scientific steps to solving the problem. By the way, these steps work for anything from the Suzuki Burgman
lights, to getting my mother's DVD player working.

1. Notice the problem
2. Get the bike home (In case of a TV it is likely already home)
3. Imagine all kinds of worst case scenarios, then forget them
4. Look up stuff on Google ("suzuki burgman" low beams burned out).
5. Start making observations, possibly write them down if you have a bad memory
6. Refrain from ripping out the guts of the bike if at all possible
7. Re-examine all your beginning assumptions about the problem.
8. Get the right tools (multimeter for testing electrical problems, axe for removing battery)
9. Consult the manual if you must
10. Talk to the person at the parts counter, you may get some ideas.

And when your part arrives, and you go to pick it up, please take the old one along, and compare the two of them before taking the new part home.

Speaking of parts, I telephoned two Suzuki dealers and got prices between $45 and $34 for the bulbs, but my local Suzuki dealer had a really excellent parts person who found me an aftermarket bulb for only $14, so I ordered two. When they arrive, we'll see if they work, of course.

Picture: A Suzuki Burgman 400 2005 headlight bulb (I think)


  1. According to Bosch, 'The only difference [emphasis added] between the HS1 and an H4 halogen bulb, is that the middle pin at the base is 1-2mm thicker. Hence the notation PX 43T compared to P43T.'

    The HS1 is now the 'standard' bulb for new two-wheeled vehicles in the United States, but sockets which support the HS1 bulb will also accept the older H4 bulb. (The thicker middle pin prevents the HS1 bulb from fitting into an automobile light socket ... but the reverse works fine).

    Approximate life expectancy of an HS1 bulb is in the order of about 300 hours. As the two bulbs in the scooter were most likely from the same batch from the same manufacturer, it's not that surprising that they burned out around the same time.

    H4 bulbs are available from the Tire for $4.35 (part 20-9107-6) and for significantly less from the Far East over eBay ;-)

  2. Reviewing my comment ... one thing I should note. The link I posted to eBay is for a 100/90W bulb (I just grabbed the cheapest H4 item that came up on the search).

    That's too bright for your scooter (which uses a 35/35W) bulb, and will most likely pop fuses on the lighting circuits.

    But 35/35W H4 bulbs are available (I expect the one from the Tire is in that range - although the online catalog does not display the wattage, it's packaged as a 'motorcycle' bulb).

    In fact, you'll see some eBayers offering bulbs labeled as H4/HS1 bulbs - as if they were interchangeable ;-)

  3. The bulbs I got from Tri-City Cycle were H4 P43T 12V 35/35W, at $4.99 each. The only slight hitch was two small tabs at the base that are only designed to prevent you from putting the H4 into the HS1 socket. They are very easy to flatten with pliers, I saw a picture on the internet, but I can't find it now.

    So I divided 21,000 km (almost all on low beam) by 70 kph average = 300 hours. Next time I will suggest that Mary Ann use the high beams a bit more to stretch the life of the bulbs.