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[Scalyback]

1951? Redditch? frame was trued by hand, etc. with people screwing the bikes together. No automated robot welders then!



I was saying the side lights could be earthing through the brake/stop bulb, being in parallel with a dodgy sidelight earth, which would change with an LED bulb, however I guess it's something totally different!


I shall give up and wait until the allotted time. Must admit, I'm very curious.


Simon

[zippy]

Nope - No welding robots - and a brazed frame . Not seen on motorcycles nowadays. Nope not that thing you said with the sidelights, - lights are off at the master switch. All earths brand new, clean and way over what a factory would put on - Also every wire put on has been tested to death on the multimeter... Its a head-scratcher alright

[zippy]

Well, not many guesses, but here it is.... The problem was within the LED all along. when the brake terminal was powered up it not only lit the brake LEDs, it supplied a voltage to the tail light supply pin. (But not vice versa) This in turn went back along the sidelight supply wire to the switch and on to the instrument and side lights, lighting them up. This was proved with a 12v supply on the LEDs brake pin and a test lamp attached to the tail supply pin on the LED and both -ve terminals attached to the case of the LED. - Sure enough the test lamp on the tail pin lit up every time.I tested all of the tail/stop LEDs I had (from different suppliers). All are the same. The fix is to fit a small diode (RS PT No 261-019) on the supply wire to the tail light to act as a 1 way valve. So the switch can supply the tail light, but the tail light cannot supply the switch. So if you've just got yourself a new stop/Tail LED and you suddenly seem to have the symptoms of a bad earth on your tail light, remember this thread and act accordingly....

[Scalyback]

neat discovery!



luckily, neither of my bullet had any problems (so far!)

[Norm]

Ok Zippy, you have those dodgy Chinese LED's been there done that but I didn't go the diode trick I threw them all in the bin but I know what you are talking about

[simon]

Actually an electrically welded frame even back in 51. Quite modern for their day.