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Degreeing cams on GS700

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    #1

    Degreeing cams on GS700

    Hello all,

    I've finally gotten around to setting my bike up so that I can degree the cams. My intent is go move the power band higher and increase peak power at higher rpm's as well. Hopefully by degreeing my cams to complement my pipe and pods I can gain some noticeable power increases.

    I plan to retard the intake cam ~3-4 degrees from stock or when it was new and then retard my exhaust cam ~7 degrees. By doing this I am hoping to get results as i posted above. This is also where my questions come. As I have never done this before I'm looking for someone who has with either an 83 750 or 85 700 that has experimented with cam timings to save me some headache. I talked to a guy in madison at a shop and he said he had a 83 750 and he put a 700 exhaust cam in and then found specs for a cam made for his bike by yoshimura and put his cams to those specs. Anyone have any information like this?

    I also need the stock cam timings so I can compare what I have now with what I should have stock. My thinking is that my camchain stretched over time and I am assuming my cams have been retarded ~3-4 degrees so I think that the only thing that I'll need to do is retard my exhaust cam an additional 3 degrees from what I have now in order to get the desired results. I need the stock timings though in order to see just how far the cams have retarded so if anyone can help me out..

    I'm going to take the gears off the cams and grind slots in the holes in order to adjust them also..

    Thanks guys
    Nick





    Last edited by Guest; 03-29-2008, 02:17 PM.
    Tags: None
    #2
    I would try 110 exhaust and 108 intake. If you want even more top end 110 for the intake but don't expect an idle under 1500 rpms.
    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

      #3

      Sure hope that long pipe and wrench isn't for turning the motor on that side of the crank.

      Comment

        #4
        Originally posted by lecroy View Post

        Sure hope that long pipe and wrench isn't for turning the motor on that side of the crank.
        Why? Is there a better way to do it? I don't want to remove the stator cover. On the rotor for the signal generator there was a hex that I assumed was to turn the motor over...

        Comment

          #5
          Originally posted by Nicholaschase29 View Post
          Hello all,

          I plan to retard the intake cam ~3-4 degrees from stock or when it was new and then retard my exhaust cam ~7 degrees.
          Retarding your intake will increase your valve to piston clearance. Good thing.

          Retarding your exhaust will reduce piston to valve clearance so when the piston is coming up on the exhaust stroke to TDC the exhaust valve may still be open too much. You need to check the Piston to Valve clearance before you start the motor. Need to have at least 75 thou clearance. If it binds when turning the engine over by hand with the sparkplugs out you'll need to stop and see what's causing it, cause you don't want to bend any valves.
          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

            #6
            On that side there's a small dowel pin on the crank that keeps the mach advance or rotor timed, if you snap it off you may be in the market for a new crank, if you can get whats left of the dowel out.
            Last edited by RacingJake; 03-29-2008, 04:19 PM.
            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

              #7
              Plus it's easier to degree with you on the side of the pointers. The other way sucks.
              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

                #8
                Originally posted by Nicholaschase29 View Post
                Why? Is there a better way to do it? I don't want to remove the stator cover. On the rotor for the signal generator there was a hex that I assumed was to turn the motor over...
                Also, & the BIGGEST reason I NEVER turn the motor on the same side as the degree wheel is that the wheel could MOVE if you are turning the crank with the nut that is on the wheel side. How accurate will the cam timing be if the degree wheel is moving? Take off the stator cover & do it RIGHT by turning the crank with the nut on the LEFT side! Ray.

                Comment

                  #9
                  Yep, the pin could crack and the wheel and slip and if your using a billet rotor you can damage it. I know pulling thos 8 or so bolts out are a lot of work compared to the rest of the job. LOL. I have to agree with Ray on this, do it right. And to Jakes point, make SURE you have enough clearance when your done!!!!

                  I normally put the dial on the starter side and the wheel on the pickup. I use a couple of large washers to sandwitch the wheel and keep it from moving. I still double and sometime tripple check this part of the setup.

                  Just my 2 cents on one other thing I see you doing. You have the dials clamping in with a mess of clamps and grips. Looks like a kids erector set. Not that there is anything wrong with that as long as nothing can move but, most people make a custom mount. I used a cobbled mount until last year for some strange reason I looked at the diameter of the cylinder studs and it turns out that the diameter is very close to a standard dial stand. Of course you would need to thread it into the head nut and you may not have enough. But with the aftermarket ones there is plenty. Very solid rig and easy to set up. It almost makes this adjustment fun to do.. But not quite.

                  Make sure when you slot the gears that they fit flat. Any bind and you could crack the cams when you go to tighten.

                  Use some brakeclean and wipe it down good, then use a little lock tight on those stupid bolts. You don't want those gears to slip...

                  One last comment about this, those two little bolts SUCK AZZ!! With the cams I use, they are worse than stock to get at. I have ground wrenchs, sockets, once even looked for cap heads but Suzuki had to use that odd ball size. I thought about drilling and tapping for a standard size but good sense popped in before my rage took over...

                  Then someone gave me some old junk cams out of some bike that actually have a torx head.
                  I believe these came from an early 1100 or 1000. If anyone knows, post!!!!

                  Comment

                    #10
                    I mount the degree wheel and turn the crank from the right side as well. Space the wheel out and use an open wrench behind it on the 17mm trigger. Be very careful when you turn the motor over as to not disturb the degree wheel. It can be done but I would not use the hex bolt that holds the trigger on.

                    Mark the wheel once TDC is established and verify it has not moved once the cams are timed. If careful, it can be done correctly without breaking the seal on the stator cover.

                    110 degree centers for both intake and exhaust should give good upper mid/high rpm results

                    Good luck, Ed
                    Last edited by Guest; 03-30-2008, 12:55 AM.

                    Comment

                      #11
                      Originally posted by oldschoolGS View Post
                      I mount the degree wheel and turn the crank from the right side as well. Space the wheel out and use an open wrench behind it on the 17mm trigger. Be very careful when you turn the motor over as to not disturb the degree wheel. It can be done but I would not use the hex bolt that holds the trigger on.
                      +1 on this, it worked fine on my 1100E. You shouldn't need anything like that snipe to turn the engine over, I had no troubles with a standard 17mm combination wrench on mine. When you are moving slow, it doesn't take a lot of force.

                      Mark

                      Comment

                        #12
                        I found this looking through my materials



                        So the exhaust cam lobe center is at 110 and the intake is at 102. I'll go get the measurements of where My cams are at later today and post them.

                        Comment

                          #13
                          I only used the pipe to more accurately control the position of the crank, there isn't much force involved in turning the engine over. The intake cam has a center of 105 degrees. The intake valve was 50 thousandths off the seat at 9 degrees BTDC and 40 degrees ABDC. Yielding the center i listed previously.

                          Comment

                            #14
                            Exhaust is the following. We measured 42.5 degrees before BDC at .050 and 3 degrees after top dead center.

                            42.5+3+180= 225.5

                            225.5/2= 112.75

                            112.75 - 3 = 109.75


                            Intake,

                            9 degrees before top dead center and 40 degrees after bottom dead center.

                            9+40+180= 229

                            229/2= 114.5

                            114.5-9= 105.5

                            Exhaust centerline = 109.75

                            Intake centerline = 105.5

                            Do those numbers sound correct?

                            Comment

                              #15
                              If you want more top end move the intake cam to 107.5. You will be close is the exhaust cam is 2 numbers bigger. This will help it pull the exhaust out of the cylinder better too. Ray.

                              Comment

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