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Spark Plugs

Discussion in 'Technical and Troubleshooting Torque' started by Wally2, Jun 17, 2007.

  1. I have just removed plugs for replacment they are NGK BP6EY
    The specs say NGK BP8ES

    Whats the difference in thes two
  2. I'd be guessing the the BP8E run a bit hotter
  3. I'm pretty sure in NGK the higher the number, the colder the plug runs.
    Double check before you use the 8
  4. Yep higher the number colder the plug
  5. Spot on.
    Have a look at the plugs you took out - if the electrode looks good and the insulator is brown or light grey colour then stick with the 6. If however there's white colouring and/or signs of blistering then the 6 is obviously too hot and you should go back to using the 8's recommended. Oh and the difference in the last character relates to the core - a "Y' means that it sticks out further from the insulator (obviously not so far as to hit the piston or you would have known about it by now but could still cause problems).
  6. Engine may have a plug fouling problem, only real reason to differ from the specified plug is to fis a problem (or that's all they had at the time).
    Are the plug threads oily, any sludge deep down next to teh insulator?
    What sort of bike is it? Was it used for commuting? If it's been used for puttering around, the hotter plug may have helped burn off deposits.

    Regards, Andrew.
  7. Its A

    The bike in quistion is a 1982 XS650
    The existing plugs are black
    I have recently had richness problem lots of black smoke
    Im in the middle of rebuilding the carbys
    Also seem to have a little blow by
  8. I'd put what you have back in for 1000kms and see how they look after that. The carbs will be masking everything as far as reading plugs at the moment.
    If you can afford them, Iridium or platinums are the go, self cleaning to a point, and last a very long time. I love my Iridiums, means I don't have to touch them for ages (GTR a hassle for plug changing).

    Regards, Andrew.
  9. What kind of spark plugs wud be recommended on a 2 stroke? I've heard of iridiums but never come across one.
  10. Sometimes these older engines need to go hotter, because they are burning more oil. the problem is you are not going to be able to do a plug chop with any great meaning.

    As suggested. Stick with the 6s and get your carby feeling right, then maybe try some 7s if the plugs are looking a bit lean
  11. 2strokes love iridium plugs, my nsr150 did, and now my nsr250 does too, heaps better in the cold, and feels smoother too. just use the ngk website to find the iridium equivalent to your stock one (as written on your fuel tank i believe), go into any auto store and order one (i got mine from supercheap as they had one in stock, plus working there = staff discount)

    def. worth the extra cost and you only have 1 plug so it wont hurt your pocket at all