Author Topic: MK5 WIRING  (Read 1813 times)

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Offline digcot65

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MK5 WIRING
« on: 27 Mar 2018 at 11:56 »
Would someone, with a `51 MK5 mind checking their battery connections.On the circuit, the +ve side of the battery goes to the + side of the ammeter which is the +ve connection of the battery.My ammeter is not original and I suspect the wiring is incorrect there/I now the -ve side of the battery does not go to the frame, where it goes I have yet to find out This would explain why the lights have to be switched on before the horn will work .Also though there is a magneto cut out switch,I cannot see a wire on the Magneto for this .Since I haven`t had the engine running for more than a few second , this is a switch I haven`t had  a chance to try. Len
« Last Edit: 27 Mar 2018 at 12:06 by digcot65 »

Offline Rex

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Re: MK5 WIRING
« Reply #1 on: 27 Mar 2018 at 14:23 »
Surely that means the horn on your bike is fed from the lighting circuit down-stream of the switch? I'm guessing the earth is connected either to the engine block or up into the headlamp shell, but wherever it goes to it's clearly adequate if the lights are working.

Offline eddie

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Re: MK5 WIRING
« Reply #2 on: 27 Mar 2018 at 14:28 »
Len,
       During the years of production of the Mks 3-5 the battery polarity did get changed, but the polarity has no effect on the wiring diagram - it's the same for positive or negative earth. Most Mark series Douglases have the earth side of the battery connected to one of the mounting bolts for the battery carrier. The live side of the battery should be connected to the ammeter, and the other side of the ammeter to the lighting switch. If these wires get reversed, the ammeter will show a charge when it should show a discharge, and vise versa. If this happens just swap the ammeter wires over again! The horn puts a greater drain on the battery than anything else, so ideally should have the wires as short as possible - the wiring diagram shows the feed being taken from the ammeter, but it is better to take a second wire from the live side of the battery to the horn (it's mounted quite close to the battery). There didn't use to be any problems with bad earthing prior to the advent of 2 pack paint and powder coating - nowadays, it's good practice to install an earth link between the engine unit and the frame to eliminate any problems.
  The ignition cutout is simply a wire from a horn type button on the handlebars to the points cover on the back of the magneto - pressing the button shorts out the spark!

  Eddie.