Spark Plugs

Discussion in 'Supersport (1974-2007)' started by Bison, Jul 17, 2023.

  1. Hi Folks,
    I read with interest the post about munching spark plugs, it prompted me to ask a question.
    My bike is a 1998 600ss, one of the last of them I believe?. Anyhow, I have NGK DCPR8E plugs fitted, they seem to last for about maybe 400 or so miles, maybe less, before cutting out, this happens on both cylinders, one at a time, it goes to running on one, usually when under load. Put a new plug in and away it goes, put the old plug in when it's cooled down and it runs fine again, for a while. The last time it happened was on a very wet ride back from Stranraer, following traffic for ages, opened it up to overtake and it went onto one, new plug fitted and away it went, the rain got even harder after that, no problems, and the same thing happens in the dry. This signifies to me that the plug is getting too hot? should I go to a colder plug?. Slightly rich, not sooted up but almost black, which might indicate a too high heat rating?, bike runs beautifully, no black smoke or any other colour from the exhaust. 2.5 turns out on the mixture screw. Do I have the wrong plug fitted? The NGKs are genuine ones.
    Interestingly my Paso owning pal has exactly the same problem?.
    Any ideas gratefully listened to.
    Thanks,
    Alan.
     
    #1 Bison, Jul 17, 2023
    Last edited: Jul 17, 2023
  2. ahh can of worms opened many varied views and opinions as to the best plugs to use
    I had issues with ngk plugs having similar issues this was with the r rated plugs that have an inbuilt resistor to stop interferance with electrical components ie ecu etc
    found even new ngk r could be an issue lovely big spark but just wouldn't run
    put in old plug it ran thought it was maybe just a one of faulty plug but have had the same issue over a number of years on varying mopeds and bigger bikes as well
    in the end I used Bosch spark plugs in my 750 ie and never had a problem
     
  3. Thanks for that Johnboy, I'll try a couple of Bosch plugs.
    Alan.
     
  4. Hi Bison, How did you get on with those Bosch plugs?
     
  5. Hi Folks,
    Well, I bought Bosch YR6DES but haven't fitted them yet. I haven't been on any of my bikes for about 10 days due to a back problem, I even had to give up working on the engine paint on my Bimota, and it's on the bench!. OK, I can't think of any other excuses!, HA!. This is a recurring problem, more so as the years go by, I'll get there with the spark plugs though, and post my findings for all to see.
    Thanks for asking,
    Alan.
     
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  6. Just a thought, they are genuine NGK plugs? I believe there are a lot of counterfeits around but how to tell I'm not sure
     
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  7. Yes, I did wonder about that. I did get this set from my local bike shop, and the guys are fairly clued up, the previous set were bought on a well known site, but from a reputable and very large shop. Who knows to be honest?. I'll get those Bosch plugs in and report back. Might be a while though.
    Alan.
     
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  8. Can only speak for myself but have fitted easily over 100 NGK D8EA spark plugs to Italian bikes and cars for over 40 years now (including a 600SS and a Monster 600) without a problem. There is definitely something else going on here, or there's "an Elefant in the room" as people now say. Hope you get the bike running correctly without the need to swap plugs regularly. Reversed coil connections? - I don't have a clue remotely.
     
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  9. Chris,
    I would tend to agree with your interpretation, in my experience plugs either work or don't, and this total non firing, then you put them in later and they work?, kind of strange, as I said, smacks of overheating?. But, easy to fit the Bosch plugs, and check all connections, I'll do that first.
    Alan.
     
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  10. Agreed, maybe not D8EA but I'm using NGK plugs in all my bikes and have had no problems.

    I used to replace them regularly as 'service items' but as they always looked fine on removal, recently I haven't bothered and so they are a good few years old and still running fine.
     
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