Spark plug recommendations?

Information relating to the Matchless G12 or AJS Model 31 650cc twin
alanjennings
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Joined: Thu May 10, 2007 5:26 pm
Location: NORTHANTS UK

Re: Spark plug recommendations?

Post by alanjennings »

Yes, I was as usual " confused!" 12 thou for the mag and I set my plugs " by eye!"
Alan [Morini] Jennings
mjf65
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Joined: Wed Oct 03, 2018 2:07 pm
Location: United Kingdom

Re: Spark plug recommendations?

Post by mjf65 »

Just checked the points gap and it seemed a bit wide at an easy 0.015, I've closed them up a bit to 0.012 and fitted new Champion plugs gapped between 0.020 - 0.024 so we'll see if that helps with starting but not tonight looking at the window in not so sunny Gloucestershire.
JEAN-NOEL
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Joined: Wed Oct 12, 2005 10:45 pm
Location: FRANCE

Re: Spark plug recommendations?

Post by JEAN-NOEL »

Hello Michael,
what is your bike ? For 1964-on and CSR G12/31 the Parts Service states N4C instead of N5C
Cheers
mjf65
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Posts: 113
Joined: Wed Oct 03, 2018 2:07 pm
Location: United Kingdom

Re: Spark plug recommendations?

Post by mjf65 »

Jean-Noel mine is a 1960 Model 31 so N5C is the standard fitment.
56G80S
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Location: N YORKS UK

Re: Spark plug recommendations?

Post by 56G80S »

IKBA but won't closing the points gap up retard the ignition if that was set while the points were at 15thou?

Johnny B
mjf65
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Location: United Kingdom

Re: Spark plug recommendations?

Post by mjf65 »

I reset them to 12 thou as detailed in the handbook, I assumed that they open up with wear? I haven't gone near points since I had a Z250 Scorpion twin in 1982.
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