No dynamo output 18M

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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rob the rebuild
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Joined: Tue Aug 26, 2003 1:00 am
Location: HAMPSHIRE UK

No dynamo output 18M

Post by rob the rebuild »

Just started the bike after about a 3 week layup without being started. Prior to this and a fairly good vapourised oil leak during the last run (noticed charging at a good few amps) found that the outside and inside of the brush cover had a good coating of ye olde Castrol XL. Ran the engine with trusty voltmeter across the terminals with the output disconnected from the bike and low and behold only 0.5 volts coming out. So cleaned the com and got 0.7 volts.
Does anyone else have some ideas as the brushes dont look soaked or is the first thing to check or is there another way of checking dynamo output.
Thanks in advance

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Biscuit
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No dynamo output 18M

Post by Biscuit »

Volts coming out? - crikey Rob we will have to improve your terminology!!!!!!!

You say you put the voltmeter across the terminals, if you mean the D & F terminals, then these should be connected together, with one probe of the meter to the joint connection and the other to earth, which way round depends on the system, ie negative or positive earth. Should get a potential of 7 to 9 volts depending on RPM.



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rob the rebuild
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Joined: Tue Aug 26, 2003 1:00 am
Location: HAMPSHIRE UK

No dynamo output 18M

Post by rob the rebuild »

Alan
Many thanks for that and I will try that tomorrow evening.
My DC electrics knowledge is very sketchy, more used to AC than DC.
Will post more tomorrow
Many thanks again.
Rob


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rob the rebuild
Posts: 16
Joined: Tue Aug 26, 2003 1:00 am
Location: HAMPSHIRE UK

No dynamo output 18M

Post by rob the rebuild »

Alan
Many thanks now reading a good 7 to 9 volts coming out.
I cleaned the brush faces and the com as they were a little dirty with oil and carbon dust. Now have horn and lights so can get it on the road again.
Many thanks again
Rob

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Biscuit
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No dynamo output 18M

Post by Biscuit »

Being well known as a pedantic sod, Rob you have a potential of 7-9 V across the D an F teminals, volts 'coming' out indeed. Even an IVcos phi man should know that. Only leg pulling!



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