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Author Topic: NF charging problems  (Read 920 times)

Mjoinson

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NF charging problems
« on: December 22, 2016, 12:54:53 pm »
Can anyone recommend someone for checking and repairing NF charging systems? Mine starting blowing fuses and then not charging so I replaced the voltage regulator with one from Escher, which didn't fix it. Dynamo is only putting out 2v which I think suggests field coils or brushes, but there's 5ohms or so between DF and D+ which suggests field coils ok and I've had the end off the dynamo to check the brushes which also looked fine (about 20mm long). Is it possible to put the  end cap back on in a way which upsets the seating of the brushes - I didn't remove them from the end cap?
I'm in Bristol. Not sure whether I'm looking for someone to take the bike to or someone to send dynamo and regulator to? To get the dynamo off I need to make/buy a tool to hold the pulley while undoing the nut - any suggestions as to good sources?

thanks

Martin
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huub

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Re: NF charging problems
« Reply #1 on: December 26, 2016, 12:58:03 pm »
any auto electrician that has been doing it for some time should be able to work on your bike,
lots of cars used to have these generators , so anybody that was rebuilding dynamo's 30 years ago should do.
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banquo

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Re: NF charging problems
« Reply #2 on: February 01, 2017, 02:11:08 pm »
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Mjoinson

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Re: NF charging problems
« Reply #3 on: April 17, 2017, 12:53:45 pm »
I got the dynamo and voltage regulator off, had them tested and they were both ok. Made sure the belt was tight. I do eventually get 14 V at really silly revs, but in normal NF riding the warning light stays on. Any thoughts on what to try next....

thanks

Martin
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banquo

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Re: NF charging problems
« Reply #4 on: April 17, 2017, 01:54:59 pm »
It is a normal dynamo, and not a Dynastart Martin?
IIRC, the Dynastart has a smaller pulley, so if someone has retrofitted a Dynastart to a non electric start bike, without reducing the pulley size, the charge will be low
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Mjoinson

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Re: NF charging problems
« Reply #5 on: April 19, 2017, 09:03:12 am »
Can't rule that out, it's one of the police ones that came in via NLM, some of which have a slightly random collection of bits. What are the two pulley sizes so I can check?

Another dumb question, should there be an earth wire from D- on the dynamo, or does it just hope to earth via the mounting bolts?
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guest107

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Re: NF charging problems
« Reply #6 on: April 19, 2017, 09:59:05 am »
bonjour diamètre externe poulie dynastar falcone civile 73 mm  ;)
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banquo

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Re: NF charging problems
« Reply #7 on: April 19, 2017, 10:07:19 am »
Can't answer that one I'm afraid; however, the Dynastart is completely different in size (larger diameter) to the standard dynamo, and of course you would have an electric start button.
If no electric start, you should have a standard dynamo.
If you do have electric start then I believe a smaller pulley is required.
On the wring diagram, D- is shown connected to earth, as is D- on the regulator.
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huub

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Re: NF charging problems
« Reply #8 on: April 19, 2017, 12:27:01 pm »
the police models had a 90 mm pulley
the charge warning light should dim as soon as the engine runs, even at a 800 rpm idle.


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banquo

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Re: NF charging problems
« Reply #9 on: April 20, 2017, 08:53:01 am »
Out of interest, where do you measure the pulley diameter?
As it's a vee-belt drive, the effective diameter is smaller than the pulley diameter.
Are we just talking about the nominal outside diameter?
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Mjoinson

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Re: NF charging problems
« Reply #10 on: April 20, 2017, 10:48:06 am »
how long should the brushes be? mine are 18mm. Worth replacing and seeing if it makes a difference? Is there any trick to refitting the end cap so they seat properly?
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huub

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Re: NF charging problems
« Reply #11 on: April 20, 2017, 07:24:17 pm »
i measured the outside diameter of the pulley,
the effective diameter depends on the width of the belt , and that diminishes with wear.
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banquo

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Re: NF charging problems
« Reply #12 on: April 21, 2017, 08:31:04 am »
Yes; that's what I meant. Thanks.
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guest107

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Re: NF charging problems
« Reply #13 on: April 21, 2017, 08:35:40 pm »
Here is the original reference of the belt ventiflex 1138 from kleber for the civil falcon of 1972 it was the same as those of the renault r5 tl 956 cm3 from 1972 to 1975 and renault r5 ls from 1974 to 1975 that is to say length Internal 610, external length 650 (9.5 x 650)
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krisztian_andre

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Re: NF charging problems
« Reply #14 on: June 10, 2017, 09:08:12 pm »
Hi,

how can I check the charging system?

Normally on bikes there is an acceptable voltage range measured at the battery at a certain RPM. Do you know these values for the NF military?

Kris
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