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Nees some help with new mods...

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    Nees some help with new mods...

    Hello everyone,
    This is a real neat site,lots of good info.
    I tried searching and could never really find answers to my questions.
    First off I have a bone stock 1977 GS 750 with 8,000 original miles.
    I have ordered a jaradine 4-1 black canister type exhaust(PN J3800-BL )
    for my bike ( I just like 4-1 better ) I alsohave a set of pods
    for it .not really sure of the brand ( I know they aren't K&N )
    I need to know if you guys think I might have to look into jetting
    up my bike?
    I am not for sure about how much performance I will see from the
    Jaradine headers or the pods....not really looking for more HP anyway...
    I know Dyna jet doesn't offer a kit for my VM carbs...
    I am going to keep all of my stock parts,etc in case I want to put it back
    stock one day....I am not chopping it up,etc
    Just trying to make it look a little better ( IMHO anyway...LOL )
    If I feal the need for speed I just climb on my ZX6R

    thanks for all of the help seems there are a ton of people who
    know there GS bikes here !!!!

    #2
    When i added my V&H 4-1 i had o rejet mine.. it is also a 77 gs750 i ended up with 115 mains and it hink it was 17.5 pilots

    Comment


      #3
      thanks for the info....I am gonna need all the help I can get8-[
      I forgot to mention I have installed dyna coils and ignition system....

      Comment


        #4
        The Dyna upgrade on the GS's with points ignition is a huge upgrade. Dyna coils rock.

        Comment


          #5
          For that pipe, I'd allow two full sizes up on the mains. For the cheaper pods, an additional 3 full sizes. A full size up on Mikuni jets is 5. I believe your stock '77 mains were either 102.5 or 100's(?). So I'd increase them by 25 (125 or 127.5).
          I'd raise the jet needles 2 positions richer than stock. If your jet needle e-clips are in the third position from the top, lower them to the bottom (5th) position. Replace all factory jet needle spacers in factory order.
          For the pilot circuit, I'd first try to make the stock #15 pilot jet work with simple richer pilot fuel screw adjustments. If the bikes pilot circuit was running well before the mods, then I'd richen the pilot fuel screws (underneath) 1/2 more turn out than their current position. If more richness needed, try an additional 1/2 turn out. Test. If no joy by about 2 1/2 turns out, then I'd go with the larger 17.5 pilot jets and return the screws to their initial settings.
          Initially set the side air screws to 1 3/4 turns out.
          Be sure to REMOVE the 2 floatbowl vent lines when running pods. Leave the vent ports open.
          Bench synch the carbs whenever the jet needles are disturbed. Vacuum synch the carbs after the bench synch.
          Before the vacuum synch, warm up fully and adjust the side air screws using the highest rpm method. Also, the ignition timing/advance must be spot on and all valve tappet clearances set correctly before the vacuum synch.
          Be sure the bike is ready for re-jetting. Clean carbs, good inner carb o-rings, float levels, new manifold o-rings and good manifolds, electrical connections all clean, etc, are necessary.
          Test for the main at full throttle, the jet needles at 1/3 throttle, and the pilot circuit at minimal throttle. Chop off and get plug reads. Do what the plugs/performance tell you.
          And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
          Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

          Comment


            #6
            Thanks a bunch Keith,I have a good friend who is a jam up Kawasaki
            Mechanic.I will Print out this thread and take it to him.
            He will be helping me do the work at his shop.
            I really appreciate your input.It is a real hoot playing with this
            30 year old bike.
            I will post before and after pics when I get done.
            do you have any more suggestions on what I can do to this bike?
            I am looking for more low end power than I am top end.
            any other ideas would be great!!!
            chain,sprockets,nitrous...( just kidding about the gas )
            where is your favorite place to buy parts from?
            again thanks for your and everyones input
            \\/

            Comment


              #7
              If you prefer the widest possible powerband and want power a bit lower in the rpm range, my personal preference with your kind of engine/mods is to set the cam timing at 106 degrees. This gives the best compromise between mid-range torque and top end HP. 107/108 tops but that starts to favor top end performance. You'll need adjustable cam sprockets to do this. Filing out the stock sprockets will work too but I just suggest the adjustable ones.
              I buy most of my parts from the Suzuki dealer or local parts shop. Most people say Bikebandit and Dennis Kirk are good suppliers.
              And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
              Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

              Comment


                #8
                Thanks again for all of the help

                Comment

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