Thought I saw some info on this forum about spark plug spec and length some time ago, but am b*****ed if I can find it now.
Want to fit new plugs on my 500 to eliminate them as source of misfiring at high revs. The current plugs are BP7EV which according to my local auto-spares shop are for the 501 motor. The standard plug quoted for the original 500 (which mine is) is about 1/4" shorter. So which one should I buy, and is it ok to interchange the longer and shorter versions?
Spark plug spec
Spark plug spec
Nick - 1979 500 Strada
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ortonpaddy
- Posts: 32
- Joined: 04 May 2008 08:22
- Location: LEICS England
Hi...
I believe that the correct plugs for the 476cc 500's are either BP7ES OR BP7EV, the "E" relates to the reach of the plug (19mm?). Hand written in the "blue" manual from NLM, I am sure mine (1982' 500) are BP7ES' I will check tomorrow.
I had a quick google search for 501's spark plug recommendation and it seems that they should be BP8E7, which is essentially the size and shape but its a "colder" plug... So I guess the shop you went to has got it wrong??
The following website shows what the parts of the refference mean on NGK plugs:
http://www.spark-plugs.co.uk/pages/technical/ngkjpg.htm
I certainly would not be tempted to fit a plug of a different length than recommended (too long could foul piston, too short and spark will be in wrong place in the combustion chamber)... Hope this helps
I believe that the correct plugs for the 476cc 500's are either BP7ES OR BP7EV, the "E" relates to the reach of the plug (19mm?). Hand written in the "blue" manual from NLM, I am sure mine (1982' 500) are BP7ES' I will check tomorrow.
I had a quick google search for 501's spark plug recommendation and it seems that they should be BP8E7, which is essentially the size and shape but its a "colder" plug... So I guess the shop you went to has got it wrong??
The following website shows what the parts of the refference mean on NGK plugs:
http://www.spark-plugs.co.uk/pages/technical/ngkjpg.htm
I certainly would not be tempted to fit a plug of a different length than recommended (too long could foul piston, too short and spark will be in wrong place in the combustion chamber)... Hope this helps
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ortonpaddy
- Posts: 32
- Joined: 04 May 2008 08:22
- Location: LEICS England
Hi again, just checked what I am sure are my "spare" plugs which came out last time I changed them. They are BPR7ES'.
I am not sure how much difference the "R" makes to a plug type, the NGK symbol code shows it means a "resistor" type construction. I am at NLM getting mine MOT'd ready for the summer (WOOO HOO!!) on Wednesday I will ask them what they recommend if I remember.
Hope you get your fault sorted... Patrick
I am not sure how much difference the "R" makes to a plug type, the NGK symbol code shows it means a "resistor" type construction. I am at NLM getting mine MOT'd ready for the summer (WOOO HOO!!) on Wednesday I will ask them what they recommend if I remember.
Hope you get your fault sorted... Patrick
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SupermotoDave
- Posts: 344
- Joined: 13 Apr 2006 18:38
- Location: Reading UK
- Contact:
I have always been told, and passed on the info, that you should avoid the R plugs as they are mainly for television interferance suppression purposes etc and the ignition needs all the help it can get, including not putting any extra resistors in the circuit. I would look to Paul for a view on this as well.
David
David