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Freshen up ideas 83-85 750/700 motor

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    Freshen up ideas 83-85 750/700 motor

    So I've been tooling around on my newly refurbed 82 Katana 1000. 16v motor with plenty o power to kill me. Been having tons of fun, but when I get back on my 84 Katana 750, well, it just seems a bit er, umm, ahh, tame shall we say.

    What I once thought was a rocket is now a little less appealing. So my question would be this: What can I do to this thing to liven it up a bit under the seat?

    As I understand, the Japanese gov't of the time regulated all motorcycles for domestic use be regulated to a max of 77 hp. Not too inspiring.
    As this pop up is a Japanese Domestic Market it is probably safe to assume it conforms to that regulation.
    It shares the same cases and internals with the 83 750e, and 85 700e. I believe, however, that the cams and possibly timing/advance/retard are different to achieve that number (77).

    So first thing I guess would be to change cams? Igniter box?
    If I wanted to go really crazy with a bore and pistons, what is available out there?

    Does anyone know if the first generation GSX-R motors will fit in?

    Any help at all is appreciated. Thinking about taking the 84 under the blade like I did the 82 Thou, and if I do, then might as well look at the motor while its all apart, right?

    BTW, the bike is currently bone stock with the exception of some cheapy aftermarket mufflers because the lovely originals developed a severe rattle somewhere inside....

    #2
    Nearly all the last motors...even the "bigger" motors...are dimensionally smaller...and none are direct swaps. You will need to fabricate new mounts for them.

    I'm looking for an early 90's Katana 1100 motor for my '81 750...but, that will make your '82 Kat seem a but er, umm, ahh, tame.

    Comment


      #3
      700 Cams are a bit more aggressive. The 750 & 700 have the same HP figures. They did it with wilder Cams & a bit more compression I believe.
      The quoted for those engines is only 84hp so not much difference. They could have just done it with the total advance given in the ignitor box to restrict it to 77hp...

      Dan
      1980 GS1000G - Sold
      1978 GS1000E - Finished!
      1980 GS550E - Fixed & given to a friend
      1983 GS750ES Special - Sold
      2009 KLR 650 - Sold - gone to TX!
      1982 GS1100G - Rebuilt and finished. - Sold
      2009 TE610 - Dual Sporting around dreaming of Dakar..... - FOR SALE!

      www.parasiticsanalytics.com

      TWINPOT BRAKE UPGRADE LINKY: http://www.thegsresources.com/_forum...e-on-78-Skunk/

      Comment


        #4
        Salty,

        I knew there was not a lot of difference, just wondering if its a viable option. Also curious to know whether or not an 1150 motor would fit in - that would indeed be a significant change!

        Surprised there has not been more response to this, I would've expected Ray or Blower bike to show up by now......

        Comment


          #5
          A set of RS flatslides will wake that puppy up. Maybe mill the head and/or block to raise compression a bit, You might bet by just milling the block to bring the pistons as near the top of the cylinders as possible.

          Comment


            #6
            How much can you mill off the head on the 700? Or, say...a 1981 16v 750?
            Last edited by Guest; 09-25-2010, 09:01 AM. Reason: ...how much wood could a wood chuck chcuk...

            Comment


              #7
              Originally posted by makenzie71 View Post
              How much can you mill off the head on the 700? Or, say...a 1981 16v 750?
              It would be best to talk to Ray or someone else about that. With the block the pistons usually aren't reaching the very top of the cylinders so that's the best place to mill first. I have a spare block that's been prepped for some Cosworths I plan on installing one of these days. It had already had some milled off by the guy I got it from, 30/1000th is what we estimated was taken off. I think I had another 10/1000th taken off when a new liner had to be installed in one hole just to true up the surface. I have to have a head done first though and it will have to wait until times are better. Can't spend the money on the head with other priorities.

              If you take very much off then you have to make sure the cams get dialed in.

              Comment


                #8
                wow .040" seems like a lot...ohhhhhh the gears! How they turn! I'm still trying to figure out what to do with my 16v motor after I get my Katana engine to throw in there. I'm thinking about tweaking it, forcing it into my '79 frame and making a straight cafe bike and selling it. Probably better if I just sell it...or keep it as a back up....

                Comment


                  #9
                  Originally posted by makenzie71 View Post
                  wow .040" seems like a lot...ohhhhhh the gears! How they turn! I'm still trying to figure out what to do with my 16v motor after I get my Katana engine to throw in there. I'm thinking about tweaking it, forcing it into my '79 frame and making a straight cafe bike and selling it. Probably better if I just sell it...or keep it as a back up....
                  Once I assemble I may have to use a thicker base gasket. The block came from Britt Turkington as well as the Cosworths. I'm pretty sure the block had been prepped for a set of the same pistons. We knew the block had already been milled when the new liner stuck up above the block surface.

                  Comment


                    #10
                    You could do a few different things. If it were MINE, I would figure out the mounts to install an 86/87 or 90 GSXR 750 engine. 1100s are taller & more headache, + you can get PLENTY of reliable power from the 750 & have easy maintenance.
                    The other choice would be cams & a piston kit for your 750 motor. That stuff with porting, & flatslides would get you to about the power level of a stock GSXR engine. GSXR 750 engine would be MY choice, with work done to it to make about 120 @ the rear wheel! Ray.

                    Comment


                      #11
                      Originally posted by rapidray View Post
                      GSXR 750 engine would be MY choice, with work done to it to make about 120 @ the rear wheel! Ray.

                      Ray,
                      How much would it cost to build an engine like that?
                      Last edited by Nessism; 09-25-2010, 10:24 PM.
                      Ed

                      To measure is to know.

                      Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

                      Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

                      Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

                      KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

                      Comment


                        #12
                        Originally posted by rapidray View Post
                        I would figure out the mounts to install an 86/87 or 90 GSXR 750 engine.
                        Ray.
                        Anything specific about those years that is better than other years?

                        I'm looking for a new engine for my 83 750e...

                        Comment


                          #13
                          More Torque less top end than the 88/89.

                          The 90 seems to be the one to go for if the figures I see quoted on the internet are correct.
                          1980 GS1000G - Sold
                          1978 GS1000E - Finished!
                          1980 GS550E - Fixed & given to a friend
                          1983 GS750ES Special - Sold
                          2009 KLR 650 - Sold - gone to TX!
                          1982 GS1100G - Rebuilt and finished. - Sold
                          2009 TE610 - Dual Sporting around dreaming of Dakar..... - FOR SALE!

                          www.parasiticsanalytics.com

                          TWINPOT BRAKE UPGRADE LINKY: http://www.thegsresources.com/_forum...e-on-78-Skunk/

                          Comment


                            #14
                            I was looking for a 750 for my project but snatched out my 1127 and crammed it in the 83 750.
                            I am happy (Little nuts too)
                            The 1127 is taller & my gas tank is setting slightly up in the front, but not noticeable, if you were not told about it you wouldn't notice.
                            Stick to the 750 for availability and less fitment headaches (less work).
                            I just like to go against the grain.

                            Good Luck!
                            Ron

                            Comment


                              #15
                              Originally posted by Nessism View Post
                              Ray,
                              How much would it cost to build an engine like that?
                              About $2500-3,000.00 with pistons, cylinder boring, porting, valve job, cams, cam sprockets, valve springs, valve seals, gaskets, assembly, cam degreeing, etc..... Another $750.00 for rods if you want to make it bulletproof. Stock rods will live @ 120 hp as long as the rider isn't an idiot & does good maintenance. Ray.

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