Announcement

Collapse
No announcement yet.

richer main jets on stock XS1100LG

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • richer main jets on stock XS1100LG

    Has anyone tried richer main jets on all four or at least the center two cylinders on a 80 special with the stock air filter / air box and stock mufflers? ... just wondering... bike runs great at all levels, and I am normally of a mind set that says if it aint broke don't fit it. but that doesn't stop me from being curious.
    Alias Larry R in Kelso WA

    When in dought, punch it.
    XS1100LG Precious current
    XS1100SF Ruby gone to a better home
    KZ900B MIA stolen (ALL bike thieves MUST GET OFF THE PLANET more politically correct ???)

  • #2
    Did yours come stock with 120 mains? Some folks run the 120 mains, others run 115 or even 110s. I run 110s in my SH bikes and they love it run great!
    Life is what happens while your planning everything else!

    When your work speaks for itself, don't interrupt.

    81 XS1100 Special - Humpty Dumpty
    80 XS1100 Special - Project Resurrection


    Previously owned
    93 GSX600F
    80 XS1100 Special - Ruby
    81 XS1100 Special
    81 CB750 C
    80 CB750 C
    78 XS750

    Comment


    • #3
      Sorry I should have mentioned that my is running 110s in all carbs.
      Alias Larry R in Kelso WA

      When in dought, punch it.
      XS1100LG Precious current
      XS1100SF Ruby gone to a better home
      KZ900B MIA stolen (ALL bike thieves MUST GET OFF THE PLANET more politically correct ???)

      Comment


      • #4
        As long as you don't mind pulling the carbs out to do the changes, you can easily give 115s or even 120s a shot. They should not be to much for it to run. But you may find the 120s make the top end a bit rich. Only way to know for sure is try it. IIRC, the 80 models, which an LG is, came stock with 120 jets anyway. And for a while Yamaha put the 120 jets in the center carbs on the LH and SH models as well, maybe the H model to, not to familiar with the standards.
        Life is what happens while your planning everything else!

        When your work speaks for itself, don't interrupt.

        81 XS1100 Special - Humpty Dumpty
        80 XS1100 Special - Project Resurrection


        Previously owned
        93 GSX600F
        80 XS1100 Special - Ruby
        81 XS1100 Special
        81 CB750 C
        80 CB750 C
        78 XS750

        Comment


        • #5
          Hey there,

          My 80 SG is correctly jetted at stock with 110 mains, so you are most likely stock with 110's as well. I live at over 7000 feet of elevation, and went down to 107.5's this summer when I rebuilt the carbs. Can't tell $.02 worth of difference compared to the 110's in terms of performance, and the fuel mileage didn't change a bit.

          Just one heck of a fine running bike in all respects!
          Howard

          ZRX1200

          BTW, ZRX carbs have the same spacing as the XS11... http://www.xs11.com/forum/showthread.php?t=35462

          Comment


          • #6
            In the old days there was a lot of discussion on this. Can not say it was ever resolved. If you look here http://www.xs11.com/forum/showthread.php?t=73 you will see the specials and of course midnights were listed as 1980 SG/LG 1981 SH/LH 110(1&4)120(2&3) not currently an issue of my concern.not saying this is definitive.
            79SF
            XJ11
            78E

            Comment


            • #7
              Hey, thanks for checking into that, however that info IS NOT accurate. I don't know why that hasn't been corrected after the discussions that have taken place over the years.

              110's across the board ARE correct for an 80 SG. Don't see any harm in doing the 110/120 combo, but it is 100% certain and factual that 110's are the stock configuration on an 80 SG.
              Howard

              ZRX1200

              BTW, ZRX carbs have the same spacing as the XS11... http://www.xs11.com/forum/showthread.php?t=35462

              Comment


              • #8
                HTML Code:
                110's across the board ARE correct for an 80 SG. Don't see any harm in doing the 110/120 combo, but it is 100% certain and factual that 110's are the stock configuration on an 80 SG.
                If that's the case then that's the case. If its wrong then it should be corrected. Not my job. Like I said not currently of concern to me.

                Is interesting that on the site I use to look up parts http://www.stadiumyamaha.com/pages/p...and/parts.aspx the mains for the sg and lg are not the same. Go figure. I don't think it is that big of a deal. Like I said, not really definitive.

                I do agree with
                HTML Code:
                if it aint broke don't fit it
                79SF
                XJ11
                78E

                Comment


                • #9
                  Originally posted by hbonser View Post
                  Hey, thanks for checking into that, however that info IS NOT accurate. I don't know why that hasn't been corrected after the discussions that have taken place over the years.

                  110's across the board ARE correct for an 80 SG. Don't see any harm in doing the 110/120 combo, but it is 100% certain and factual that 110's are the stock configuration on an 80 SG.
                  Well, yours may have 110's all the way across, but some came with 120's on 2 and 3. But you're correct that some (maybe even many) came with 110's all the way across. Yamaha did try on some of them though to richen the center cylinders to make them run cooler at higher throttle, I think they found it was not a significant difference and changed that. They also had some 80's with a plug over the idle jets like the earlier carbs, and later they didn't, so how they came was likely based on how far into the model year it was built.
                  Cy

                  1980 XS1100G (Brutus) w/81H Engine
                  Duplicolor Mirage Paint Job (Purple/Green)
                  Vetter Windjammer IV
                  Vetter hard bags & Trunk
                  OEM Luggage Rack
                  Jardine Spaghetti 4-2 exhaust system
                  Spade Fuse Box
                  Turn Signal Auto Cancel Mod
                  750 FD Mod
                  TC Spin on Oil Filter Adapter (temp removed)
                  XJ1100 Front Footpegs
                  XJ1100 Shocks

                  I was always taught to respect my elders, but it keeps getting harder to find one.

                  Comment


                  • #10
                    Here's a quote from one of the tech tips... " '80G & '81H had larger main jets on 2-3 than 1-4 for the same reason, SG & SH did not."

                    For my info that I am quoting as gospel, I'm going off the factory manual, and what was in my carbs. Has anyone with an SG found anything different than 110's across the board in their carbs? Maybe I missed that being said somewhere, sorry if I did.

                    Question: Was there a Vetter fairing that went on the Special, or was that a Standard model only deal?

                    Possibly there could have been somewhat restricted airflow on faired bikes, and Yamaha took the chance that people would put fairings on their Standard bikes and jetted a bit richer on 2&3?

                    It is what it is, run what you got and enjoy!
                    Howard

                    ZRX1200

                    BTW, ZRX carbs have the same spacing as the XS11... http://www.xs11.com/forum/showthread.php?t=35462

                    Comment


                    • #11
                      Many things are tru and many are fuzzy about these things, 30yrs. Maybe there should be a registry of folks who have owned each model since new and done all their own repairs that can certify what they have found to be stock The carbs are certainly the most controversial. also for sure better to err on the rich side than the lean. Waste a little gas or melt a piston.
                      79SF
                      XJ11
                      78E

                      Comment


                      • #12
                        Vetter fairings go/went on both standard and special models. AAMOF they use the same mounting hardware. Hard bags are another story however.
                        Cy

                        1980 XS1100G (Brutus) w/81H Engine
                        Duplicolor Mirage Paint Job (Purple/Green)
                        Vetter Windjammer IV
                        Vetter hard bags & Trunk
                        OEM Luggage Rack
                        Jardine Spaghetti 4-2 exhaust system
                        Spade Fuse Box
                        Turn Signal Auto Cancel Mod
                        750 FD Mod
                        TC Spin on Oil Filter Adapter (temp removed)
                        XJ1100 Front Footpegs
                        XJ1100 Shocks

                        I was always taught to respect my elders, but it keeps getting harder to find one.

                        Comment


                        • #13
                          My 80SG had 110's(1&4) & 120's(2&3) and it runs great.

                          Interestingly enough my 80G had 115's(1&4) 120's(2&3). Replaced all with 117.5's as they were trashed by the PO. Runs great also.

                          Have been looking at a Dynojet kit for the Venture to see if I can smooth out the top end and get a few more MPG.
                          Richard

                          Comment


                          • #14
                            Well, son of a gun, sounds like Yamaha was using stuff out of the parts bin to make our bikes with the variety of carb jets we all have, relative to what we may or may not think we should have!

                            The factory manual does say 110's for the SG, and the combo jet set up for the G.

                            I don't know all the nomenclature, so what is an LG (Midnight Special?), an SF, etc? Is there a thread somewhere that tells the nuances between them, or anyone able to post it in this thread?
                            Howard

                            ZRX1200

                            BTW, ZRX carbs have the same spacing as the XS11... http://www.xs11.com/forum/showthread.php?t=35462

                            Comment


                            • #15
                              LH L=Midnight Special H=81
                              H=Standard 81
                              LG L=Midnight Special G=80
                              SG S=Special G=80
                              G=Standard 80
                              SF S=Special F=79
                              F=Standard 79
                              E=Standard 78
                              Richard

                              Comment

                              Working...
                              X