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Low Cost / High Performance GS1100E Head work

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    Low Cost / High Performance GS1100E Head work

    I thought I would post this to document my conclusions for improving the performance of my GS1100ED head. I asked around and got input from some knowledgeable people here on the board and thought I would summarize my finding and conclusion below. This might be helpful to anyone going through their engine and trying to decide how to spend their money.

    I have a GS1100ED with most of the common/popular street modifications. A GS1100ED that you want to drive on the street, but hop it up nicely but stay very street able without compromising reliability.

    I'm trying to achieve a performance level above a stock 1150 (GS1100E is 109hp (80-82) 111 (83) hp and GS1150 124 hp stock) say 130-135 hp.

    My configuration is 1166 kit, 0.340 webcams, 1150 36mm CV with Stage III, Accel coils, Yoshi 4:1 race pipe, APE springs, APE clutch hub, HP gears/oil pump, top end oiler. I will probably also put on 36 mm (slingshot) CV Flatslides.

    As it turns out the 16V heads are very sensitive to valve seat configuration and can make much better flow numbers (and therefore more hp) with some minor machine work. In fact duing the early 80's engineers recognized that minor variations within the factory production tolerances in head work were resulting in observable differences in ET's on otherwise identical stock GS1100E's motors. So a nice balance without going to far, and killing gas mileage too much is:

    A.) is to do go 1mm oversize on the intake to 28mm (same as the stock 1150 valves)

    B.) If stock valves (1100/1150 23 mm exhaust and 28mm 1150 intake) then get them backcut or buy new stainless steel valves that don't need back cutting.

    C.) Get a modern radius cut valve job on your seats using a Serdi

    http://www.aperaceparts.com/headwork.html


    D.) Minor clean up porting to smooth the area where the seat were opened up for the 28mm valves.

    Ray's quote....

    Originally posted by rapidray
    Go 1 mm bigger on the intakes & back cut the stock exhaust valves. If you have to buy ALL new valves get the Kibblewhite Black Diamonds. Also, do a RADIUS valve job & blend the guides & you will gain a BUNCH of airflow. Ray.
    and more from Terry.....

    Originally posted by headsbikesmopars
    A good bowl job with the radiused valve job and back cut valves will give you a solid piece indeed. Enough to make 150 @ the wheel if you wanted to do that. And with oversize valves you WILL fly, low tens easy. 130 plus.
    This will flow about 90-95 cfm v.s. stock 75-78 cfm if I remember my numbers correctly. So you are basically getting the equivalent of stock Gixxer 1100 head performance with your GS1100 head.

    Then depending upon the 36mm CV or 36mm Slingshot carbs, the combo above is conservatively between 130-140 hp (v.s. 111 stock), and will be easily capable of having your front wheel off the ground. You will be in the mid 10's quarter mile v.s. mid 11 stock.


    Any U guys want to correct my number please let me know. But this is basically the upshot of asking alot of questions from some guys that know. My preference is to take the a low mileage stock head with stock GS1150 intake , stock exhaust ; back cut them as these are all Suzuki parts.


    If you go bigger than this on the head, then you will need some really large jets and are starting to get into the 38 mm regime for carbs. Ask Chef he is at 1.5 mm oversize on intake and minor porting. He is a big guy and needs the extra horses. If you are under 220 lbs, then 135 hp is going to fly. Start thinking about suspension upgrades will all that hp as well.


    Pos

    P.S this is 1100 16V stuff, but probably still applies in general (as to head work) to other 16V and 8V motors.

    EDIT Here are Some Summary from numbers comapring a Stock head, to two other proted heads. Mine has 1150 28/23mm backcut valves and Nick's is ported a little more aggressive but with stock 27/23mm backcut valves



    Last edited by posplayr; 12-25-2010, 11:43 PM.

    #2
    Same things I do to a lot of motors every year. Ray.

    Comment


      #3
      Ray

      Thanks; you were one of the guys I consulted so eveybody else knows.
      Jim
      P.S. I added your prior post as a quote to the above post.
      Last edited by posplayr; 02-21-2009, 03:55 PM.

      Comment


        #4
        Great info Pos, getting ready to yank the motor on the 82. Seems it would make the most sense to do engine mods at this time. Kinda on the fence with what I want to do..

        Great start to thread!

        jw

        Comment


          #5
          I had an 1166 kit with an 1100 head that had +1mm stainless valves and 325 lift megacycle cams. It ran a best of 10.11 @129(132HP or so). I took those valves and put then into an 1150 head. No porting, but I switched to a set of 348 lift web cams and went 9.77 @135(140HP or so). It only cost me a valve job at a local car engine builder to make the switch + a set of 1150 studs.

          The 1166 kit with stock head, stock cams, Mikuni Flatslides, Dragpipe, good ignition made 128 HP. That same motor with stock pistons made 113 HP. All at the rear tire.

          I think to guarantee the HP your looking for I would upgrade to some Mikuni flatslides and go with the 1150 head.
          Last edited by Guest; 02-22-2009, 09:53 AM.

          Comment


            #6
            Originally posted by jwhelan65 View Post
            Great info Pos, getting ready to yank the motor on the 82. Seems it would make the most sense to do engine mods at this time. Kinda on the fence with what I want to do..

            Great start to thread!

            jw
            Those 1150 carbs are jetted for what you have now. Let me know of your changes and I can help you get the jetting right.
            1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
            1985 GS1150ES stock with 85 Red E bodywork.

            Comment


              #7
              Sad part about all this is now you can pick up a hayabusa cheap and with minor tuning mods and no engine work make about 170-175 at the rear wheel. The frame also can handle the HP.

              Hard to beat a old GS for drag racing but I made the decision in 1999 they were obsolete as a fast street bike combination.

              Comment


                #8
                Originally posted by cbxchris View Post
                Sad part about all this is now you can pick up a hayabusa cheap and with minor tuning mods and no engine work make about 170-175 at the rear wheel. The frame also can handle the HP.

                Hard to beat a old GS for drag racing but I made the decision in 1999 they were obsolete as a fast street bike combination.
                I couldn't care less if a Hayabusa, CBR, ZXR or whatever is faster than my GS.
                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


                  #9
                  Originally posted by Nessism View Post
                  I couldn't care less if a Hayabusa, CBR, ZXR or whatever is faster than my GS.
                  Don't get me wrong I don't either. I had 2 GS1150's at the same time I had hayabusa's. But I have/had chosen not to chase performance mods when engines like the hayabusa are available. Also after getting used to them its so much easier to tune and work on more modern engines. I liked the GS's for what they are. I just rode my cbx last week. Yeap by today's standards its a slug but I like to hear it run.

                  Comment


                    #10
                    I say get one of each.

                    Comment


                      #11
                      cbxchris

                      I don't think this is about chasing the modern street bike performance, that is clearly a loosing proposition. This thread is about cheap horsepower gains from head modifications in the context of.

                      I'm trying to achieve a performance level above a stock 1150 (GS1100E is 109hp (80-82) 111 (83) hp and GS1150 124 hp stock) say 130-135 hp.
                      Clearly, there are street performance levels attainable today which were unheard of 20 years ago and it comes with little modification to stock rides.

                      In the bigger picture, for me this is about making an old "fast" bike a little faster and safer when driving moderately illegal speeds. I want to be safe at twice the posted speed but not 3 times posted speed . Get your Hayabusa out if you need that.

                      Personally, I never rode a street bike (legally) until the end of 2007. So it is has been a wonderful walk through motorcycle history and racing history for me to explore this early 80's technology. That is why I prefer my 83 GS1100ED and 86 1100 Gixxer to any of the later stuff and am glad I lucked into it. Yes I am adding performance, but most of it is period (pre 93) performance upgrades. I think the most modern thing going on the Gixxer is a early 90 double clicker Fox shock. The GS1100 might get a modern R/R and I don't need to explain why on that. OK yea the most modern rubber I can fit on my wheels.

                      I'm sure there are plenty of guys enjoy working with the old stuff more then the high production tuned factory stuff. I have no interest in that.

                      Pos

                      P.S. This is what is giving me a woody right now.

                      Last edited by posplayr; 02-22-2009, 02:06 PM.

                      Comment


                        #12
                        Originally posted by chef1366 View Post
                        Those 1150 carbs are jetted for what you have now. Let me know of your changes and I can help you get the jetting right.
                        Chef,

                        Probably gonna leave the engine set up as is for now, Im sure it will be much improved from what I had. Just engine paint for now.

                        thx

                        Comment


                          #13
                          Originally posted by posplayr View Post
                          I don't think this is about chasing the modern street bike performance, that is clearly a loosing proposition. This thread is about cheap horsepower gains from head modifications in the context of.



                          Clearly, there are street performance levels attainable today which were unheard of 20 years ago and it comes with little modification to stock rides.

                          In the bigger picture, for me this is about making an old "fast" bike a little faster and safer when driving moderately illegal speeds. I want to be safe at twice the posted speed but not 3 times posted speed . Get your Hayabusa out if you need that.

                          Personally, I never rode a street bike (legally) until the end of 2007. So it is has been a wonderful walk through motorcycle history and racing history for me to explore this early 80's technology. That is why I prefer my 83 GS1100ED and 86 1100 Gixxer to any of the later stuff and am glad I lucked into it. Yes I am adding performance, but most of it is period (pre 93) performance upgrades. I think the most modern thing going on the Gixxer is a early 90 double clicker Fox shock. The GS1100 might get a modern R/R and I don't need to explain why on that. OK yea the most modern rubber I can fit on my wheels.

                          I'm sure there are plenty of guys enjoy working with the old stuff more then the high production tuned factory stuff. I have no interest in that.

                          Pos

                          P.S. This is what is giving me a woody right now.

                          Agreed POS,
                          If you want modern day performance, I don't believe there are enough mods available for GS to make it happpen, we might be able to hang with a few 600's but even if we get close the handling would be way out matched. Dosnt matter to me much, everything about these old machines is pure fun!!!

                          Comment


                            #14
                            Originally posted by posplayr View Post
                            My configuration is 1166 kit, 0.340 webcams, 1150 36mm CV with Stage III, Accel coils, Yoshi 4:1 race pipe, APE springs, APE clutch hub, HP gears/oil pump, top end oiler. I will probably also put on 36 mm (slingshot) CV Flatslides.
                            Your off to a good start

                            Add a 1150 head that has strip/street porting and I'd stick a fork in it. You could drop down to a 14 T counter sprocket just to pi$$ off the oem tire
                            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
                              What if

                              Agreed POS,
                              If you want modern day performance, I don't believe there are enough mods available for GS to make it happpen, we might be able to hang with a few 600's but even if we get close the handling would be way out matched. Dosnt matter to me much, everything about these old machines is pure fun!!!
                              If you put a GS seat on a 600, and then call it a GS you can do it .

                              Pos

                              Comment

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