Hi all whilst out on my 1966 A65L I had to touch the horn button the sound was just a faint pip and the engine seam to stop for a split second, further down the road I tried it again and the same happened the bike was running great, back home for some reason I put the lights on and they just glowed checked the battery and this was showing 12.6v the horn and dip switch are a couple of years old, any idea where to start looking thanks Roy ???
Hi Roy,
It does not sound like a dead short otherwise the fuse would have blown. 12.6v is fully charged so the lights should have been bright. Perhaps disconnect the horn and see if the lights are better. If not then there could be a partly broken wire somewhere. The usual places are near the headstock as the wires are moved when the handle bars are turned.
Dave.
I would do a load test on the battery by charging it fully and then switching on the headlight to see how long it takes to dim. At face value, it sounds as though the battery is either failing or was not charging properly and may have only taken 2-3 A demanded by the horn to drag the battery voltage down.
Hi,
I would have thought that once started and whilst riding along the alternator would have compensated for a slightly weak battery. At full output surely the alternator should be able to run the ignition, lights and horn all at the same time so any problem with the battery would be when riding quite slow or at idle.
Dave.
As suggested, it could be the battery or it could be the battery not charging properly possibly due to an alternator, wiring or rectifier problem. As well as doing a load test on the battery, it would be worth putting a voltmeter across the battery to make sure you get at least 14 V when the engine is revved.
Thanks for your replies and suggestions but wont be able to check them out till a few days time, Roy
Hi all still not able to work on my problem yet but if the horn is duff would pressing the push button act like a kill switch and if I took the head light bulb out of its holder and put the probes from a voltmeter in place with the engine stood would it read 12v plus and is there another way to test a battery other than leaving the lights on still open for suggestions thanks Roy
If the horn was shorted internally then pressing the horn button would effectively short out the battery. The easiest way to check this for this is to put the multimeter across the horn terminals and measure the resistance which normally should be a few Ohms.
I've got quite a few batteries on my bench and, although they all show at least 12.6V when charged up, they are all duff - essentially, their capacity has been reduced to a small level. So, simply measuring their voltage will tell you very little which is why the load test is needed - putting a headlight bulb across these batteries will show that it will dim very quickly because the battery cannot maintain 3-4 A for very long.
Thanks spaceman never had it explained to me what volts,amps,ohms,resistance had to do with the flow of electricity I was under the impression that showing 12+volts every thing was ok. Roy
Thanks for the suggestions new horn and battery sorted the problems, the new horn does not have +or-on the terminals but the terminals are insulated from the horn body can the brown/blue and brown/black wires go to any terminal when mounted on the frame. Roy
Glad the problem's now sorted - it doesn't normally matter which wire goes to which terminal.