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    Plug temperature question

    I notice the manual for my 78 GS750EC says to use NGK B-8ES spark plugs and I find the prior owner has been using NGK G-7ES plugs.
    Can someone out there tell me if the B-8ES plugs are a cooler plug? Did the prior owner possibly switch up one notch to a hotter plug?
    If so should I stay with the hotter plug or go back to using the manual recommended B-8ES?
    I think I read somewhere where the factory tends to determine plug choice based on the bike being used under its worst conditions.
    The prior owner, like myself, is a very conservitive rider rarely running the engine at its top end capabilities and spent most of the time just cruising aroud at in-town speeds. Could it be the prior owner, due to his riding habits was possibly constantly fowling plugs so as a result his mechanic possibly switched to a hotter plug?
    I appreciate the wisdom and advice of GS plug geru's out there.
    GS750GUY

    #2
    Originally posted by GS750GUY View Post
    Could it be the prior owner, due to his riding habits was possibly constantly fowling plugs so as a result his mechanic possibly switched to a hotter plug?
    my thoughts exactly

    my plugs tend to foul if i stay too long at under 3000rpm
    yes, the carbs are clean etc etc

    but i sort that out by not riding below the 4k rpm
    GS850GT

    Comment


      #3
      Originally posted by GS750GUY View Post
      I notice the manual for my 78 GS750EC says to use NGK B-8ES spark plugs and I find the prior owner has been using NGK G-7ES plugs.
      Can someone out there tell me if the B-8ES plugs are a cooler plug? Did the prior owner possibly switch up one notch to a hotter plug?
      If so should I stay with the hotter plug or go back to using the manual recommended B-8ES?
      I think I read somewhere where the factory tends to determine plug choice based on the bike being used under its worst conditions.
      The prior owner, like myself, is a very conservitive rider rarely running the engine at its top end capabilities and spent most of the time just cruising aroud at in-town speeds. Could it be the prior owner, due to his riding habits was possibly constantly fowling plugs so as a result his mechanic possibly switched to a hotter plug?
      I appreciate the wisdom and advice of GS plug geru's out there.
      GS750GUY
      Or maybe they were out of B8ES, someone told him it would go faster, or maybe he was riding in the Yukon in February.
      I'd try the B8ES if all else is original and see how it works.
      http://img.photobucket.com/albums/v5...tatesMap-1.jpg

      Life is too short to ride an L.

      Comment


        #4
        Many times the plugs are changed to hotter plugs because they are fouling. Rather than fix the cause of the fouling, they just put in hotter plugs. If the bike is jetted correctly, you should get along fine with the B8ES.

        By they way, riders don't come much more conservative than my wife.
        Here is a shot of two spark plugs. One of them, TheCafeKid has just removed from his (former) GS1100G after about 5,000 miles. The other is from my wife's 850L and it has about 15,000 miles on it.
        Which one is which?



        By the way, my wife's plug went back into her bike.
        TCK's plugs got rescued out of the trash and got put into my parts box as spares.
        If he keeps changing them at 5,000 mile intervals, I will have free plugs for life.
        sigpic
        mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
        hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
        #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
        #2 son: 1980 GS1000G
        Family Portrait
        Siblings and Spouses
        Mom's first ride
        Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
        (Click on my username in the upper-left corner for e-mail info.)

        Comment


          #5
          Originally posted by Steve View Post
          Many times the plugs are changed to hotter plugs because they are fouling. Rather than fix the cause of the fouling, they just put in hotter plugs. If the bike is jetted correctly, you should get along fine with the B8ES.

          By they way, riders don't come much more conservative than my wife.
          Here is a shot of two spark plugs. One of them, TheCafeKid has just removed from his (former) GS1100G after about 5,000 miles. The other is from my wife's 850L and it has about 15,000 miles on it.
          Which one is which?



          By the way, my wife's plug went back into her bike.
          TCK's plugs got rescued out of the trash and got put into my parts box as spares.
          If he keeps changing them at 5,000 mile intervals, I will have free plugs for life.
          And I will....so just keep stockin up my friend :P

          Comment


            #6
            Run the B8ES, if you see there is a problem, probably won't be, then start looking for the cause & remedy.
            1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100

            Comment


              #7
              I'm guessing your wife's plug is the one on the right.
              GS750GUY

              Comment


                #8
                Actually, If i remember correctly, the one on the LEFT is his wifes...the right one is one of my throwaways..

                Comment


                  #9
                  Ok, I'll be the one to ask. Why did you change out perfectly good plugs ?

                  Comment


                    #10
                    Originally posted by GS750GUY View Post
                    I'm guessing your wife's plug is the one on the right.
                    Sorry, you lose.


                    Originally posted by TheCafeKid View Post
                    Actually, If i remember correctly, the one on the LEFT is his wifes...the right one is one of my throwaways..
                    Yes, you remember correctly.


                    Originally posted by don_gibb6512 View Post
                    Ok, I'll be the one to ask. Why did you change out perfectly good plugs ?
                    I asked the same thing as he was tossing them into the trash can. He said something about keeping the fresh. That's when I pulled my wife's plug for comparison.

                    I have always changed plugs based on appearance and measurement, not time or miles. Depending on the bike/car/van they were in, the mileage changed, but they usually go considerably longer than most people think. When the new plugs are installed, if there is a gas mileage improvement, it's too small for me to notice. Wife's bike is approaching 17,000 miles on her plugs. I have yet to change the plugs in my Wing since I got it. No idea when the previous owner changed the plugs, but I got the bike with 91,000 miles on it, it now has over 136,000. I change the plugs in my vans every 100,000 miles only because they are platinum-tipped and I have to remove the front passenger seat to get to them.

                    .
                    sigpic
                    mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
                    hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
                    #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
                    #2 son: 1980 GS1000G
                    Family Portrait
                    Siblings and Spouses
                    Mom's first ride
                    Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
                    (Click on my username in the upper-left corner for e-mail info.)

                    Comment


                      #11
                      The plug on the left is from your wife's bike.
                      What do I win???
                      1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
                      1985 GS1150ES stock with 85 Red E bodywork.

                      Comment


                        #12
                        Originally posted by don_gibb6512 View Post
                        Ok, I'll be the one to ask. Why did you change out perfectly good plugs ?
                        It wasnt perfectly good. It had over 5k miles on it. They were in the bike when I bought it, no idea how long theyd been in there, so I put fresh ones in. I was going on a long trip, and covered everything I could think of. And Yes, i change my plugs (would normally change at 7-10k miles, but these were questionable) and oil (EVERY 2k miles or less) at short intervals. Some call it paranoia, I call it preventative maintanence.

                        Comment


                          #13
                          Originally posted by chef1366 View Post
                          What do I win???
                          I'm afraid that all you win is a chance to answer my next question.

                          .
                          sigpic
                          mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
                          hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
                          #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
                          #2 son: 1980 GS1000G
                          Family Portrait
                          Siblings and Spouses
                          Mom's first ride
                          Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
                          (Click on my username in the upper-left corner for e-mail info.)

                          Comment


                            #14
                            B6ES-- north pole-- too hot for most of us.
                            B7ES hot-- winter time
                            B8ES cooler general use
                            B9ES colder-- hi performance or summer time riding
                            B10ES super cold -- death valley desert racing ultra high performance engine lots of timing advance


                            but a hotter plug will damage piston crown and top ring land by helping detonation and pre-ignition during improper combustion (carbon build up, bad jetting,wrong timing all factor in)

                            when it runs bad... bad things happen to the parts inside the engine
                            SUZUKI , There is no substitute

                            Comment


                              #15
                              Some call it preventative maintenance, some call it paranoia, I say it's doing what suits you.
                              1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100

                              Comment

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