The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: jhg1958 on 16.08. 2024 17:47

Title: Spark plug
Post by: jhg1958 on 16.08. 2024 17:47
I think I am an idiot.  I wanted a spare set of plugs so I took mine out to take to the motor factor shop.  When I got there I found they were Champion L82C. A short reach plug.  I can only assume these were the ones that was in the bike when I got it.  I would have put them in to prevent things dropping into through the plug hole.

I see I bought some NGK B7ES but the Haynes manual states NGK B7HC.

I am a bit confused perhaps I need to go back and buy some B7HC plugs.

On the positive side, the GF ran fine on the L82C. Just a forgiving bike I suppose.

John
Title: Re: Spark plug
Post by: groily on 16.08. 2024 18:36
It's all about the reach - and the cyl head. Iron head = short eg NGK B6HS etc, alloy 3/4 inch as in B6/7ES or Champ N4/5 or equiv. You're not an eejit!
Title: Re: Spark plug
Post by: limeyrob on 12.09. 2024 18:45
Its not a disaster if you put a short reach in a long reach (ally) head by mistake, but it is if you put a long reach in an iron head so check and check again.
Title: Re: Spark plug
Post by: Colsbeeza on 13.09. 2024 11:07
John, I presume you have an alloy head on your Flash?. I run L82C's in my 1960 Flash with iron head, and they are very reliable.
Col