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Yamaha 1100 vs 1200 exhaust question

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  • a1965gt
    Resident Guru
    • Feb 2004
    • 907

    Yamaha 1100 vs 1200 exhaust question

    Does anyone know if using a Yami 1100 expansion chamber on a 1200 motor will increase bottom end power or top end RPM? I have heard there is supposed to be a performance increase but I'm looking for more information.
    Thanks
    James
    1996 XP All the usual mods
    http://www.pwctoday.com/showthread.p...17#post4380117

    1996 WaveBlaster II 1200 conversion in progress
    http://www.pwctoday.com/showthread.php?t=477231
  • Myself
    PWCToday.com Is My Home Away From Home
    • Jun 2006
    • 7767

    #2
    Re: Yamaha 1100 vs 1200 exhaust question

    The stinger size is a bit smaller on the 1100. I'm pretty sure in 99 they they reduced it to 1100 size on the 1200. It helps give a bit more top end.
    http://www.facebook.com/twinlakesjetskirepair

    '89 Kawi 650SX 42.4 GPS
    +3" stock pipe, ported ex. manifold, drilled waterbox, blueprinted pump, Ocean Pro ride plate

    '99 Yama GP1200 65U 61.8 GPS
    ported cylinders, matched cases, milled head, blueprinted pump, long ride plate

    '96 Seadoo HX 717 53.13 GPS
    light porting, massaged cases, lightened flywheel, port matched manifolds, Rossier pipe, stubby pump cone

    Comment

    • a1965gt
      Resident Guru
      • Feb 2004
      • 907

      #3
      Re: Yamaha 1100 vs 1200 exhaust question

      Originally posted by Myself View Post
      The stinger size is a bit smaller on the 1100. I'm pretty sure in 99 they they reduced it to 1100 size on the 1200. It helps give a bit more top end.
      I think your right, I just looked up the part numbers and the part number for the 1100 (63M-41121-00-94) is the same as the 99 GP1200 part number
      The 97/98 GP1200 part number is 65U-41121-00-94.

      I think I also read somewhere that the the 63M chamber only has two water injection ports at the end of the inner chamber where the 65U has three water injection ports.
      Can anyone confirm?
      1996 XP All the usual mods
      http://www.pwctoday.com/showthread.p...17#post4380117

      1996 WaveBlaster II 1200 conversion in progress
      http://www.pwctoday.com/showthread.php?t=477231

      Comment

      • a1965gt
        Resident Guru
        • Feb 2004
        • 907

        #4
        Re: Yamaha 1100 vs 1200 exhaust question

        So I found some more information but just as confused as ever....
        I have heard from racers back in the day that running a 1100 pipe was a popular mod. GroupK, who I highly respect, saysrunning an 1100 pipe on a 1200 requires race gas. The 99 GP1200's use the 1100 pipe with pump gas but I also read that the Riva CDI is only for use on 97-98 GP1200's which make me wonder if the 99 GP1200's also have different timing curves that make it possible to run on pump gas????

        Anyone know if the 99GP1200's use a different timing curve than previous 1200's?
        1996 XP All the usual mods
        http://www.pwctoday.com/showthread.p...17#post4380117

        1996 WaveBlaster II 1200 conversion in progress
        http://www.pwctoday.com/showthread.php?t=477231

        Comment


        • #5 Unapproved
          Re: Yamaha 1100 vs 1200 exhaust question

          I am not aware of any difference between them besides the exhaust.

          Comment

          • iptamenos
            PWCToday Regular
            • Jan 2008
            • 87

            #6
            Re: Yamaha 1100 vs 1200 exhaust question

            if i remember the grey color pipe was only in the 1100 and works fine but if you put the grey to the 1200 65u motor there is detonation on the pistons i think that all the gp1200 and suv and xl1200 using the same pipe color blue . tim judge using grey color pipe in their motors but i never discuss if is using race gas .

            Comment

            • a1965gt
              Resident Guru
              • Feb 2004
              • 907

              #7
              Re: Yamaha 1100 vs 1200 exhaust question

              iptamenos, I got you message but your inbox is full
              1996 XP All the usual mods
              http://www.pwctoday.com/showthread.p...17#post4380117

              1996 WaveBlaster II 1200 conversion in progress
              http://www.pwctoday.com/showthread.php?t=477231

              Comment

              • Grumpy Old Guy
                • Dec 2003
                • 26167

                #8
                Re: Yamaha 1100 vs 1200 exhaust question

                No on the timing curves theory as ALL 1200s use the same cdi including jet boats.
                sigpic

                Comment


                • #9 Unapproved
                  Re: Yamaha 1100 vs 1200 exhaust question

                  All 1100 are silver 63M pipe.
                  97 GP1200 is silver 65U.
                  98 GP1200 is blue 65U.
                  99 GP1200 is blue 63M.

                  63M pipe can safely be run on the 1200, no mods or race gas required.

                  Comment

                  • a1965gt
                    Resident Guru
                    • Feb 2004
                    • 907

                    #10
                    Re: Yamaha 1100 vs 1200 exhaust question

                    Originally posted by SkiSwede View Post
                    All 1100 are silver 63M pipe.
                    97 GP1200 is silver 65U.
                    98 GP1200 is blue 65U.
                    99 GP1200 is blue 63M.

                    63M pipe can safely be run on the 1200, no mods or race gas required.
                    From what I have learned you are correct.

                    IMO, The 63M pipe can be used with 41cc (or bigger) domes but higher compression or advanced timing (Riva CDI) and 63M pipe requires race gas.
                    1996 XP All the usual mods
                    http://www.pwctoday.com/showthread.p...17#post4380117

                    1996 WaveBlaster II 1200 conversion in progress
                    http://www.pwctoday.com/showthread.php?t=477231

                    Comment

                    • iptamenos
                      PWCToday Regular
                      • Jan 2008
                      • 87

                      #11
                      Re: Yamaha 1100 vs 1200 exhaust question

                      Originally posted by a1965gt View Post
                      iptamenos, I got you message but your inbox is full
                      empty

                      Comment

                      • iptamenos
                        PWCToday Regular
                        • Jan 2008
                        • 87

                        #12
                        Re: Yamaha 1100 vs 1200 exhaust question

                        so 1999 gp1200 that is using blue pipe is using the old 1100 silver pipe ?

                        i thought that all the gp1200 1997-1999 are using the same pipe .

                        Comment

                        • iptamenos
                          PWCToday Regular
                          • Jan 2008
                          • 87

                          #13
                          Re: Yamaha 1100 vs 1200 exhaust question

                          Originally posted by a1965gt View Post
                          iptamenos, I got you message but your inbox is full
                          the curves are different between 1100 and 1200 because of the port's .
                          pipe is different between 1100 and 1200 also the exhaust gasket .

                          so about which cylinder is better still cant figure out need to spend time and money to be sure with test results .
                          i have found a good recipe to my triple 1200 and i think i will stop there .
                          i am tired figure out why my pistons have a failure but after money and time now it spins very fast .

                          Comment

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