Author Topic: Electrics  (Read 2183 times)

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Offline digcot65

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Electrics
« on: 03 Apr 2018 at 11:41 »
On to the next item to be looked at.There is a magneto cut-out button on the handlebars, but there is no wire going into the magneto for this and if the button is pressed while the engine is running, nothing happens.  Another item is that the ammeter doesn`t show a charge or discharge while running,  I also found someone had put the terminals on the battery the wrong way round which doesn`t help things..Now I`ve checked the contacts on the dynamo there is zero o/p with the engine running.
Is it straightforward to remove the dynamo, just in case there is anything to keep a lookout for, I`ve removed the large clamp but something is still retaining the dynamo.  Now I have the tank and dynamo brackets off I can see a screwed wire connector near the top of the magneto, which must be the cutout connection but the wires from handlebar button go into the loom, but there is no spare wire near the magneto
« Last Edit: 03 Apr 2018 at 12:12 by digcot65 »

Offline digcot65

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Re: Electrics
« Reply #1 on: 03 Apr 2018 at 12:52 »
Just traced the lead from the magneto cut out switch through a loom to near the rear of the frame and it was soldered to an earth tag.Very efficient, when you pressed the magneto cut out switch it connected the button end of the wire to earth and the other end to earth!!!! .Rectified another fault.
 I was offered the bike at a reasonable price and the day after agreeing to buy it, the bike was advertised in  Cars and Classics at much higher price,  saying all matching numbers they arn`t, it  runs well it didn`t run, recommissioned by a garage fully tuned and with a full MOT!!
I am very pleased I bought it at the right price and not off the advert.No spark leads both corroded didn`t start electrics faulty and no MOT.Len

Offline eddie

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Re: Electrics
« Reply #2 on: 03 Apr 2018 at 17:21 »
If your bike has stood idle for a considerable length of time, the dynamo has probably lost it's residual magnetism - so will not generate any output. To restore the magnetism, first recharge the battery, then without starting the engine, remove the 2 wires from the dynamo - the 2 terminals are marked 'F' & 'D'. Take a length of wire and connect the live side of the battery to the 'F' terminal for a couple of seconds (be careful, the dynamo will draw about 5 amps). Then replace the 2 wires and start the engine - the dynamo should now generate a charge - if not, there is a fault in either the dynamo or the voltage regulator.

  Eddie.

Offline digcot65

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Re: Electrics
« Reply #3 on: 04 Apr 2018 at 08:54 »
Thanks again, if it comes to it, how does the dynamo come out.I have removed the thin metal strap and the" alloy bridge" piece, it seems to still be held at the front end but I don`t want to force anything.I now remember when I restored a Rover some years ago which had stood for 19years, I had a problem with the dynamo not charging.I now seem to remember being told to run the dynamo with the connection polarities reversed and it did the trick. I just couldn`t remember the trick. Len

Offline eddie

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Re: Electrics
« Reply #4 on: 04 Apr 2018 at 10:31 »
The dynamo has a retaining stud at the front end, with a (sort of) dome nut on it.

  Eddie.

Offline digcot65

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Re: Electrics
« Reply #5 on: 04 Apr 2018 at 12:12 »
Thanks, I saw the small nut, but didn`t want to touch it in case it was something else not connected with the dynamo.The brushes look good so tomorrow I`ll try connecting it to a battery as you suggested.Len

Offline digcot65

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Re: Electrics
« Reply #6 on: 05 Apr 2018 at 08:51 »
Morning, quite bright as well as compared to the weather forecast.I repolarized the battery this morning, then connected F and D together and with the battery+ve to these two and the battery -ve to the case and the dynamo ran, so one less thing to do. Now to give the armature a clean a coat of paint on the case refit it and see if the system is charging.Crossing fingers.

Offline Hampshirebiker

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Re: Electrics
« Reply #7 on: 05 Apr 2018 at 09:36 »
I don't recall Eddie telling you to connect F & D together.

Offline digcot65

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Re: Electrics
« Reply #8 on: 05 Apr 2018 at 10:15 »
He didn`t but after re polarising the battery, as Eddie said  it worked. If D and F are connected together and the battery +ve is connected two these two wires then the battery-ve is connected to the dynamo case it should run, which it did.  When the bike is 100% as I want it, I will sell it on. I did this with all the cars I restored and then went on to another one.In this case, I was in the process of buying another Douglas, I agreed on a price with the seller and even paid for a courier to collect the bike.This should have been on a Friday but sadly the owner died on the Thursday. I am hoping when everything is settled by his relatives I will be offered the bike again and since I don`t want two bikes it will have to go.At some time, not too long ago the bike has been restored, the frame has been powder coated and the brightwork re-chromed.The engine is in excellent order. However, it had apparently been left at a motorcycle repair shop to have some work done but when I collected it sold as seen there were quite a few faults with the bike.So what the shop had actually done I have no idea. Len
« Last Edit: 06 Apr 2018 at 08:10 by digcot65 »

Offline Hampshirebiker

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Re: Electrics
« Reply #9 on: 05 Apr 2018 at 12:04 »
Understood Len.