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    Rear wheel horsepower

    The '83 GS 1100GL specs show 94 horsepower stock. What would the rear wheel horsepower be? Is there a guestimation of a percentage of loss in the shaft assembly etc?
    1983 GS 1100 Guided Laser
    1983 GS 1100 G
    2000 Suzuki Intruder 1500, "Piggy Sue"
    2000 GSF 1200 Bandit (totaled in deer strike)
    1986 Suzuki Cavalcade GV 1400 LX (SOLD)

    I find working on my motorcycle mildly therapeutic when I'm not cursing.

    #2
    Okay, found approx 15% loss somehwere. Is that a good ballpark?
    1983 GS 1100 Guided Laser
    1983 GS 1100 G
    2000 Suzuki Intruder 1500, "Piggy Sue"
    2000 GSF 1200 Bandit (totaled in deer strike)
    1986 Suzuki Cavalcade GV 1400 LX (SOLD)

    I find working on my motorcycle mildly therapeutic when I'm not cursing.

    Comment


      #3
      The shaft drive will chew up some power for sure, but not sure how much. Other thing I'd say is I doubt that engine makes 94 hp. Closer to 84 I'd guess.
      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


        #4
        Originally posted by 1948man View Post
        Okay, found approx 15% loss somehwere. Is that a good ballpark?
        that is the number for chain drive; likely much less for shaft drive.

        Power is measured at the output shaft so we are talking about the difference between chain vs. shaft with a certain about of bearing and rear tire resistance added in.

        Since a chain is so relatively efficent, I would figure no more than 1/2 is in the chain or 7.5%.

        If the shaft was twice as lossy as the chain then that would put you at 7.5+15=22.5% for a shaft

        Comment


          #5
          Typical drive line loss is 15% with a driveshaft.
          Typical loss with chain and sprockets is 5-10%.

          Daniel

          Comment


            #6
            Originally posted by 7981GS View Post
            Typical drive line loss is 15% with a driveshaft.
            Typical loss with chain and sprockets is 5-10%.

            Daniel
            I guess I nailed it then

            15% loss is the typical derating for engine hp between output shaft and rear wheel.

            Comment


              #7
              Factory brochure had 92hp @ 8000rpm and some articles have 98hp @ 8700rpm and 94hp @ 8500rpm for the GS1100G, GL, GK.


              Sure someone didn’t pull that 15% out of a hat? I’d like to see some real test results.
              Last edited by Guest; 12-22-2010, 03:00 AM.

              Comment


                #8
                the difference is that one number is measured at he CRANKSHAFT, not output. the other is wheel.

                you also have to factor in different dyno setups configured differently in ways, or generally inaccurate.

                Comment


                  #9
                  Originally posted by Graham View Post
                  Factory brochure had 92hp @ 8000rpm and some articles have 98hp @ 8700rpm and 94hp @ 8500rpm for the GS1100G, GL, GK.


                  Sure someone didn’t pull that 15% out of a hat? I’d like to see some real test results.
                  Yea, if that G has a chain it would probably put down 150 RWHP

                  Comment


                    #10
                    I just retired from Fedex 11/30, but I had a customer with a dyno. He builds dragsters and competes on a national level. I took my bike to him Monday and it dynoed at 72 rwhp. I guess if Ed is right with the estimate of 84 or so, the 72 rwhp is in line with he expected loss. I was wanting to see how my engine was doing and decide if I want to keep working with the bike or get something else. He surprised me by saying the engine sounded great and was not far off at all. It was a little rich at the bottom and a little lean above 7000 rpm but would pull to 9000 rpm. My tank is spewing some small rust particles and I have an inline filter which could cause a slight starvation at high rpms. The tank has a lousy PO Kreme job so I'm dreading trying to strip it and redo. I have shimmed the valves, soaked and cleaned the carbs and synced the carbs with a Morgan Carbtune. The needle has no spacer (PO removed). I tried putting 1 or 2 of the little washers in but it balked in mid-range.I haven't done the coil relay mod. I think I can justify getting a dynojet kit but am looking at a Bandit today and may try to trade my 'Cade towards it so Who knows? Thanks for the replies.

                    Jim M
                    Last edited by 1948man; 12-23-2010, 09:58 AM.
                    1983 GS 1100 Guided Laser
                    1983 GS 1100 G
                    2000 Suzuki Intruder 1500, "Piggy Sue"
                    2000 GSF 1200 Bandit (totaled in deer strike)
                    1986 Suzuki Cavalcade GV 1400 LX (SOLD)

                    I find working on my motorcycle mildly therapeutic when I'm not cursing.

                    Comment


                      #11
                      Originally posted by 1948man View Post
                      I just retired from Fedex 11/30, but I had a customer with a dyno. He builds dragsters and competes on a national level. I took my bike to him Monday and it dynoed at 72 rwhp. I guess if Ed is right with the estimate of 84 or so, the 72 rwhp is in line with he expected loss. I was wanting to see how my engine was doing and decide if I want to keep working with the bike or get something else. He surprised me my saying the engine sounded great and was not far off at all. It was a little rich at the bottom and a little lean above 7000 rpm but would pull to 9000 rpm. My tank is spewing some small rust particles and I have an inline filter which could cause a slight starvation at high rpms. The tank has a lousy PO Kreme job so I'm dreading trying to strip it and redo. I have shimmed the valves, soaked and cleaned the carbs and synced the carbs with a Morgan Carbtune. The needle has no spacer (PO removed). I tried putting 1 or 2 of the little washers in but it balked in mid-range.I haven't done the coil relay mod. I think I can justify getting a dynojet kit but am looking at a Bandit today and may try to trade my 'Cade towards it so Who knows? Thanks for the replies.

                      Jim M

                      Your numbers track very closely to a 22.5% loss for the shaft drive as compared to 15% for chain drive. Given the folloing data:


                      gs1100E: 108 horsepower stock; dynoed at 92 rwhp(this a nominal number reported here at GSR by a few members for stock bikes)

                      gs1100gl:94 horsepower stock; dynoed at 72 rwhp

                      You will find that the following formula applied to the data yeilds the following losses 14.8% 23.4%

                      %Loss = 1-Dyno/Rated


                      Using the previously specified parameters of 15%(chain) and 22.5%(shaft) you get the folloing calculated RWHP numbers which are very close.




                      Chain ---------SHAFT DRIVE
                      estimated ----estimated

                      108 ----------------94 hp

                      91.8 -------------72.85 RWHP
                      15.0% ----------22.5%



                      Last edited by posplayr; 12-22-2010, 10:47 AM.

                      Comment


                        #12
                        Originally posted by posplayr View Post
                        Your numbers track very closely to a 22.5% loss for the shaft drive as compared to 15% for chain drive. Given the folloing data:


                        gs1100E: 108 horsepower stock; dynoed at 92 rwhp(this a nominal number reported here at GSR by a few members for stock bikes)

                        gs1100gl:94 horsepower stock; dynoed at 72 rwhp

                        You will find that the following formula applied to the data yeilds the following losses 14.8% 23.4%

                        %Loss = 1-Dyno/Rated


                        Using the previously specified parameters of 15%(chain) and 22.5%(shaft) you get the folloing calculated RWHP numbers which are very close.




                        Chain ---------SHAFT DRIVE
                        estimated ----estimated

                        108 ----------------94 hp

                        91.8 -------------72.85 RWHP
                        15.0% ----------22.5%



                        I remember something about factory hp being taken at the output shaft of the transmission (old cycle magazine article).
                        How can compare chain and shaft hp loss without having the same gear ratio and tire size or having a true engine hp? Got to have the engine hp without chain and shaft and rwhp from the same bikes not factroy hp from a new GS. Apples and oranges? And if ratio and tire size aren’t the same between bikes your not comparing chain to shaft.
                        Estimate is like an opinion, everyone has one.

                        Comment


                          #13
                          Originally posted by Graham View Post
                          Estimate is like an opinion, everyone has one.
                          and yours is showing,


                          it is unbelievable how you twisted that argument around.

                          Hp and torque are functions of RPM. Gear ratio or load doesn't matter.

                          What is even worse is your completely avoiding the data
                          Last edited by posplayr; 12-23-2010, 03:34 AM.

                          Comment


                            #14
                            My skunk was noticeably quicker than my 1000g with similar setup...
                            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


                              #15
                              Originally posted by salty_monk View Post
                              My skunk was noticeably quicker than my 1000g with similar setup...
                              But Dan your two bikes were different colors so that would invalidate any comparison

                              Comment

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