Nh 350

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Petebarn
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Nh 350

Postby Petebarn » Tue Sep 24, 2019 10:05 pm

Evening all help needed out for run on the nh done about 20 mls and it stopped no spark left it over night ,next morning it started 2 kick I suspect the mag is there anything I can replace on it or is it a rebuild that's needed,cheers Peter

john.whiting
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Re: Nh 350

Postby john.whiting » Wed Sep 25, 2019 5:34 am

Likely the secondary windings are cactus.......get an exchange armature from one of the repairers.

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chris.shearwood
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Re: Nh 350

Postby chris.shearwood » Wed Sep 25, 2019 12:25 pm

I suspect the condenser in your magneto is defective. This is a good web site for more info:
http://www.brightsparkmagnetos.com/
1946 4G, 1950 NG and 1951 VH

Petebarn
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Re: Nh 350

Postby Petebarn » Thu Sep 26, 2019 9:27 am

Thanks Chris have you had or anyone else had dealings with brightspark, ,I'm looking to get my mag reconed any recommendations would be greatly appreciated

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Bob.Murphy
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Re: Nh 350

Postby Bob.Murphy » Thu Sep 26, 2019 11:38 am

Earlier this year I built up four modified MO1 Mags from parts with 'Brightspark' condensers - They produce good sparks.

The trick is to remove the original condenser and replace the coil connections with something set in an infill medium. I experimented with 'Clearcast Plastic' (too brittle), a machined nylon block (too difficult to machine to a good fit) and finally epoxy resin (preferred). I learned a lot.

Regardless of my OCD experimentation the actual 'Brightspark' condensers are good ;) .

(I wouldn't recommend building a mag from disparate parts - the bits don't fit together well or run true and there are a surprising amount of design changes over the years. My lathe & mill had a lot of work to do).

Bob.
My avatar shows the late Len Rich in 1970 with the bike I now have - a 1958 Ariel VH

Petebarn
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Re: Nh 350

Postby Petebarn » Thu Sep 26, 2019 6:49 pm

Thanks Bob I don't have access to a lathe so looks like I'll have to send it off and have it repaired ,any recommendations as to best place to get it repaired

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alan.moore
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Re: Nh 350

Postby alan.moore » Thu Sep 26, 2019 6:53 pm

Petebarn wrote:Thanks Bob I don't have access to a lathe so looks like I'll have to send it off and have it repaired ,any recommendations as to best place to get it repaired


Peter
I have had three done by Tony Cooper and have always received a good service and decent price

have a look at this post for details
viewtopic.php?f=7&t=9181&hilit=tony+cooper

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alan
1939 VH Redhunter;1942 RN WNG;1951 Triumph 6T Thunderbird;1970 BSA B175 Bantam;1986 Yamaha SRX600 single
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Gui.dorey
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Re: Nh 350

Postby Gui.dorey » Fri Sep 27, 2019 5:59 am

Petebarn wrote:Thanks Chris have you had or anyone else had dealings with brightspark, ,I'm looking to get my mag reconed any recommendations would be greatly appreciated


I had a magneto for my BSA Sloper done by Brightspark. It didn’t require much - a good clean and replacing the original condenser with one of their solid state ones. I was quite happy with the service and communication and never had any problems with the mag anymore. This was about 2 years ago.
Cheers
Gui

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Re: Nh 350

Postby tstewart » Fri Sep 27, 2019 7:50 am

Just been through similar on my NH350. I found a local vintage tractor enthusiast who looked at the mag and found the magnets were weak.
He said my mag had been rewound. Also the bearing shorted to earth sometimes. The tractor guy had built a jig for magnetising mags. I did also have a carb problem.
1952 Ariel NH350, 1960 Ariel Arrow, 1955 Francis Barnet Falcon 197cc, 1954 Norton Dominator.

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Re: Nh 350

Postby Petebarn » Fri Sep 27, 2019 4:30 pm

Thanks for info I'll give Tony cooper a ring next week as it looks like bright spark are in France so postage could be expensive


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