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[Adrian]

Paul Goff also has bike-friendly (compact-ish and fan-less) LED H4 replacements, these might meet your specs but I don't know about shipping costs to Australia, though. You can now get deeper inner headlight rims which will give a little bit of extra breathing room in the headlamp casquette and possibly enough for the speedo cable AND the LED's heat-sink.



http://www.norbsa02.freeuk.com/goffyWhyNotLEDs.htm



A.

[zonggong]

Thanks for the links and additional suggestions. The motorbike specific LED headlamps look to be better quality than what I have been using. I'll do some more investigation on the bike. I don't have an oscilloscope to check the cleanliness of the DC into the lamps but I think Stinkwheel is on to the probable cause of the problem. The lamp ran beautifully straight from the battery when the bike wasn't running. An in-line diode could assist short term, and I'll try that first, but I think a new reg/rectifier may be the long term solution. The HID is also an interesting solution. I have some of these on my 4WD and they are good, but the rats nest of connectors and wires behind the headlamp could make finding a spot for the ballast challenging - depending on it's size. I'll have to wait for the weekend to do some more tests and will report back after that.

[zonggong]

Just following up with this problem. I managed to get hold of a scope meter and have found that there is an irregular negative voltage spike of about 25V . Possibly one of the reg/rec diodes is damaged. I couldn't detect the frequency due to the variations of engine speed but could have been about 100Hz (scale was 0.02 ms) . LEDs don't like this so I guess that is the cause of the problem. I've ordered new rectifier /regulator. Thanks for the help and advice.

[Balf]

I had a similar problem (posted earlier) with a noisy supply with my sat nav. I cured it with an inductor in the +ve feed and a 1000uF capacitor across the output. Semiconductors don't like spikes. I think the noise was coming from my electronic ignition.

[Adrian]

I notice the Sparx regulator/rectifier instructions are adamant that the bikes they're fitted to MUST have suppressor spark plug caps fitted, or the reg/rectifier will be knackered by the interference. I have one on ASBO14. I also have a BT-H (CDI) magneto on ASBO14, and the magneto instructions are adamant that I should NOT fit a suppressor spark plug cap.



That's handy, isn't it? (



Presently by way of compromise I'm using an unsuppressed plug cap with an Iridium resistor plug, which seems OK for starting and running, we'll see how both components hold up under use.



A.

[Aethelric]

If it's a spike, then a diode fitted close to the bulb (possibly in the feed to the dipswitch) in parallel with the bulb to short out any negative spikes should help. A schottky diode would be best.

[zonggong]

It is an interesting idea that the ignition could be causing the spike. Thanks Adrian. The bike is 12V and has the standard points ignition. Seeing that it is a negative spike it could be caused by the coil. I'll try a suppressed plug cap, and depending what happens will install a diode close to the lamp and see how that works. Thanks again.

[zonggong]

I've changed the existing Indian plug cap to an NGK with 5 k ohm resistance and the negative spike has disappeared. The bike still starts and runs OK. I temporarily hooked up a LED headlamp and that seemed to function well. A longer run is necessary to be sure but this is a good start. Thanks for all the suggestions.