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GSX750 Dot head cam question?

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    GSX750 Dot head cam question?

    Purchased a 1990 GSX750F engine that supposedly was last in a later model Bandit. I'm intending on using the Dot 22cc dome head on my GS1100E. It would be safe to assume that the cams in the head are not GSX-r but before I ditch them I'd like to verify this for sure.

    Did Suzuki specify their cam numbers by lift at the lobe or at the valve? In inches or metric?

    I'm assuming at the lobe and in inches but figured I'd ask before assuming.

    If anyone has expertise in this conversion I'd like to PM you when I get into predicaments. Promise to try to work out problems and research as much as I can first.

    #2
    all lift values are in the manuals

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      #3
      Found the info I was after. The bellow info was copy/pasted. I've also found that most cam specs are valued in inches.

      To get lift figures, you have to determine the base circle of each camshaft, then subtract that from total lobe height to get lobe lift. Then multiply that by the rocker ratio, then subtract valve lash. That will give you total net valve lift, at the valve seat.

      Or, you could just set up a gauge on an assembled head and change cams out to get net lift numbers for the specific cams.

      Or go one step further, and do it on an assembled engine,(or a dummy engine) with a degree wheel attached, then you can get duration numbers as well ...which are just as important as net lift numbers, if not more so ....

      I'm learning a little more about duration and understand this to be the degrees at the crankshaft that the valves are open..... So this leads me to believe that duration can only be determined at the crankshaft and not by measuring degrees at the camshaft on a bench.
      Last edited by Guest; 08-25-2016, 08:56 PM.

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        #4
        Next Question about the DOT head.

        Looks like the best recommended solution to deal with the lack of overlap near the rear of the cam chain between the DOT head and my GS1150 block is to use a GS template gasket made of copper and forget about the minimum overlap between the two parts. After looking at the wide variety of thicknesses available in the GSX-r gaskets and considering adding material to my 1150 block I'm leaning towards going this rout.

        Basically I'm after a recommended high heat epoxy that I can use to build up this area on my 1150 block. Any recommendations? I only need a little.

        My buddy helped me metal lathe all the plugs I need for the head and block for this project out of 7075 aluminum but he doesn't want to try to weld on my block.

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          #5
          Chris, I build these. Call me at 714,356.78four5.
          Ray.

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            #6
            Thanks Ray.

            I've already been bugging you through text's and I GREATLY appreciate you talking to me on this thing. I'd be in WAY WAY over my head otherwise. I'll call you next time I'm tinkering on the head as I have questions about removing the oil tubes or not and modifying the tins.

            Only reason I ask here is to spread the for mentioned bugging around a bit.

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              #7
              Check the letter stamped into the end of the camshaft. "B" stamped cams are from the 88 slingshot 750 and are the hottest. I just put a set of 89 cams in my Bandit, and they swapped in a milder exhaust cam for that year. The Katana 1100 and GSXR1100 used the same cams.

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                #8
                Thanks Roger.
                Seems lots, or all, of these 80'S and 90"s GSX cams have 28A cast into them. I've got a set of 1100F cams now that I have verified have the lift I'm after.
                I figured I wouldn't be able to verify duration till I degree the engine but they do have the B on the end so that is re-assuring.

                Forsetti cam chain is on the way now from Australia. Hopefully I'll be able to post some bottom end build up pics soon.
                Last edited by Guest; 10-23-2016, 11:17 AM.

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                  #9
                  103_5304.jpgPutting new rings in the cylinders. I'm told that 150 grit ball hone is ideal for getting new rings to seat correctly. Lowest grit I can find is 180 and most common is over 300 grit. Any recommendations before I spend $50.00 on a 3" ball hone? Tried to load more than one photo but not able. engine is further along than that as bottom end is assembled.
                  Last edited by Guest; 03-20-2017, 10:16 PM.

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