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38mm Vs Flatslide Carbs

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    38mm Vs Flatslide Carbs

    OK my GSX1100 already has a set of big pistons and a bit of head work. I will be buying a dyna 2000 ignition and slotted cam sprokets for it (winter upgrades).
    The carbs fitted are still the 34mm OEM fitted carbs.
    I understand the 38mm carbs form the L&M GSXR750 work very well. But I also see mention of some GSXR flatslides in this site. I am looking at E-bay to get the carbs.
    Which carbs work best to give me most power but still maintaining good ROAD driveability? If the flatslides work well what size do I need?
    I'm also told that the 38mm CVs gain a lot from a dyno jet kit. Is that the same for the flatsides?
    Currently the bike is putting out 105bhp on the dyno. I want this up to 125 bhp this winter.
    All advice would be happly recieved.

    #2
    Get the real thing at once instead.
    I'd buy these: Mikuni RS36

    They're good for up to around 155bhp and are quite driveable, I love my set.

    Comment


      #3
      38 mm flatslides

      the 38 mm flatslides compromise midrange/low end performance but the topend hit is worth it

      Comment


        #4
        Don't mistake stock CV flatslides for RS flatslides. Two different animals.

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          #5
          how big is your piston kit? if you are over 1166 I would go with the 38 rs flatslides, they are smooth easy to tune and as you do more mods they will still be enough carb. my bike is 1229 cc with other mods and the carbs are great. if you plan on keeping the cc displacment smaller go with the 36 rs flatslides

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            #6
            Thnaks for the advice. Where any bikes fitted with these RS36 or 38 carbs as standard? If which?

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              #7
              Not that I know of, but tuning shops sell them. Or look for them on ebay like the link in my post above.
              Considering your goal of 125bhp I'd definitely buy a set of RS36:s, I've used them on 1168, 1200 and 1300cc engines and are very pleased with them.
              When my rear wheel puts out around 150-160bhp:s I'll switch to RS40:s, not until then.

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                #8
                OK so after much looking it seems that the RS carbs are expensive and the 38mm CVs are as common as rocking horse *@%^$*@%^$*@%^$*@%^$ - but the 36mm from the bandits are common and cheap. I currently have 34mm is it worth the bother of changing to 36mm? I've also seen some 40mm CV for sale would these be too big for a mildly tuned GSX1100?

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                  #9
                  Hi Club Members,

                  After read through the posts of this topic, I have a question.
                  If it is going to use the RS38 flatslide carbs, dose it need to change the 4 rubber intake boots(maniflods between carbs & engine)? If yes. where can find the right one?
                  Also, is it the RS36 just fit to the standard intkae boots of GS1100?
                  Addy

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                    #10
                    my 38 flatslides fit right into the stock boots

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                      #11
                      Yeah I just bought a set of GSXR 38mm CV carbs for $75 bucks. Compare to Flatsides at $600 bucks it's a no brainer. If I don't like them I can always put them on E-Bay and get $150 out of them. They fit the OEM boot on my 1100E but I'm going to grind out the inside to match the intake port.

                      Jake
                      1166cc 1/8 ET 6.09@111.88
                      1166cc on NOS, 1/8 ET 5.70@122.85
                      1395cc 1/8 ET 6.0051@114.39
                      1395cc on NOS, 1/8 ET 5.71@113.98 "With a broken wrist pin too"
                      01 Sporty 1/8 ET 7.70@92.28, 1/4 ET 12.03@111.82

                      Comment


                        #12
                        Jake what year are the GXSR carbs for your GS11

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                          #13
                          Trouble is I can not even find any 38mm carbs
                          Some 36mm flatslides did come up on e-bay but at ?280 that was too rich for me!
                          So I now have three choices;
                          Leave the current 34mm on the bike and wait for some 38mm CV or 36mm flatslides at a reasonable price.
                          Fit 36mm CV (loads about and very cheap) but will this give me any power increase? Will it be worth the bother?
                          Fit 40mm (seem to be a few around) but will these be too big for a 1170cc engine with a mild tune?
                          Oh I forgot the fourth choice Fit 33mm Flatslides (again common and cheap) but will these be any better than 34 or 36mm CVs.
                          Too many choices and too little money 8O

                          The answer to the previous post is 38mm CV were fitted to GSXR750L & M I think they where 90 and 91

                          Comment


                            #14
                            Originally posted by bostrom155
                            Jake what year are the GXSR carbs for your GS11
                            I really don't know. The carbs I bought from this guy said he had then on a GS1100E too. They are Mikuni with number 18D3 K198 printed on the side if that helps??. I do know that they are bigger than my OEM CV 34 carbs.

                            i'll post a few pic's on my www site.

                            Jake
                            1166cc 1/8 ET 6.09@111.88
                            1166cc on NOS, 1/8 ET 5.70@122.85
                            1395cc 1/8 ET 6.0051@114.39
                            1395cc on NOS, 1/8 ET 5.71@113.98 "With a broken wrist pin too"
                            01 Sporty 1/8 ET 7.70@92.28, 1/4 ET 12.03@111.82

                            Comment


                              #15
                              I posted a few pic's of the carbs, to view just tab on my www button below.

                              I would guess that my carbs are 90's to 95's.

                              Take a look at StripBike.com they have a lot of stuff on that web site too.

                              jake
                              1166cc 1/8 ET 6.09@111.88
                              1166cc on NOS, 1/8 ET 5.70@122.85
                              1395cc 1/8 ET 6.0051@114.39
                              1395cc on NOS, 1/8 ET 5.71@113.98 "With a broken wrist pin too"
                              01 Sporty 1/8 ET 7.70@92.28, 1/4 ET 12.03@111.82

                              Comment

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