Author Topic: mk5 spark plugs  (Read 2721 times)

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Offline dalgrae

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mk5 spark plugs
« on: 20 Jul 2014 at 15:48 »
Can someone please tell me what are the correct spark plugs for my mk5 do I also run surpressed or not


Regards Colin

Offline grav220

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Re: mk5 spark plugs
« Reply #1 on: 15 Aug 2014 at 15:58 »
Hi
In previous posts Eddie has recommended NGK B6HS, for all the postwar bikes.
At the moment I have Champion J8C, which is the plug originally listed in the Handbook for my T35 (1947). I was about to order the B6HS, but have just noticed that the J8 is a 3/8" reach and the B6HS is 1/2" reach. Is this right?
Graham

Offline eddie

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Re: mk5 spark plugs
« Reply #2 on: 15 Aug 2014 at 18:18 »
Colin/Graham,
                     The T35 (Mk1) had different heads compared with later models. The recommended plugs for the Mk1 were Lodge C14 or Champion J8 (3/8" reach) whereas later models used Lodge H14 or Champion L7 (1/2" reach). These days NGK B7HS plugs seem to suit our purposes better on the later models (I have had several Champion plugs collapse on my Dragonfly - usually the sealing powder gives up and the porcelain centre moves up and down with the compression). I would only recommend B6HS if the bike is going to be ridden gently, and therefore more likely to foul up the colder plugs.
  With regard to the use of suppressor plug caps - I have always been led to believe that unsuppressed caps should be used on machines with magnetos - evidently they put less strain on the windings.

  Regards,
                 Eddie.

Offline dalgrae

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Re: mk5 spark plugs
« Reply #3 on: 15 Aug 2014 at 18:24 »
My local classic bike shop who also runs a Mark Douglas himself recommended to me Champion L82C which I have fitted to my bike these also show as alternative to NGK B6HS but I think as the person who completely rebuilt my magneto says they are non surpressed which he recommends,

Regards. Colin

Offline grav220

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Re: mk5 spark plugs
« Reply #4 on: 15 Aug 2014 at 18:55 »
Thanks for the info Colin and Eddie
The NGK B6S seems to be the J8 equivalent, with a 3/8" reach. I think I will go for that. Presumably a B7S would be a colder version, but I don't ride hard so the hotter one should be OK.
Graham

 

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