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16 valve 750 camshaft appearance

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    16 valve 750 camshaft appearance

    I received an ebay head and I have read about the oiling problems associated with the 16 valve engines.
    I have also read that these camshafts have very thin surface hardening.
    Is this camshaft serviceable?
    These surfaces are smooth to the touch with no evident pitting.
    Is this the way they look? Or has this cam sustained damage?
    Is the hardened surface gone? That which appears dull grey here is actually a glistening hardened surface.
    I suspect this is norm?



    I



    Last edited by Guest; 03-19-2012, 07:01 PM.

    #2
    This is the exhaust cam, probably intake cam looks much better. The reason for that is the gap on the rocker arm, which causes "the problem". Measure the cam, and check it in the manual. If there's pitting etc. on the surface of the lobes it means they are worn and camshaft has to be replaced.
    Cams from 1100 are exactly the same. You just have to change the sprockets (in 1100 are smaller).
    There's no sense to repair this cam (it's possible, but not worth it), better find another one in better condition.
    If there's no wear at all, I would leave them (after checking service manual).
    Last edited by Guest; 03-19-2012, 08:05 PM.

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      #3
      the bearing surfaces usually get marks from running any length of time. As long as they're in tolerance things should be fine. The lobes however, look like they've been running in contact with the rockers for quite some time. I have a feeling those might be goosed in that repect........still .....seen worse in running motors
      Last edited by Guest; 03-20-2012, 10:56 AM.

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        #4
        The lobes and journal surfaces actually do measure out to spec all across the camshaft. Checked it today with quality micrometer.

        Here is my last question. Do these cams have a rather flat surface on the leading edge of the lobe? In other words, do these engines really flip those exhaust valves open very abruptly?

        The followers have some flattening as well which I suspect are typical.

        My trouble is that I am much more used to my VW water-cooled engines which all have much more gradual opening of the valves....much more smoothly rounded cam lobes. That holds true even with the more performance camshafts I have for them. Most of my VW engines' cams have oem German surface hardening and those surfaces look good for easily half a million miles.

        I have just not performed much internal bike engine work on these larger bikes and am not used to their "particulars." All the camshaft photos (very few) in the Clymer manual appear to look identical in the cam lobe discoloration. But, I have no reference available for the question I am currently posing regarding the abrupt lift. And, yes, I have diligently searched this forum for additional info.

        Edit: or are there flats spots on the leading aspect of the lobes due to the engine having run with too-tight-of-valves??
        Last edited by Guest; 03-21-2012, 12:28 AM.

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          #5
          Those are some high milege camshafts that looks like they had oil. The cam bearing areas look good.
          If you have to you can run them but I'd look into a newer set of cams and rockers.
          What do the rockers look like for that exhaust cam?
          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.

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            #6
            That cam looks normal for a 750 exhaust cam because of the way the rockers arms are. Measure the lobes for excess wear.
            Best thing to do is get an 1100 exhaust cam and use a set of 750 intake rockers on the exhaust side. That is what I did when I had my 750.
            750 and 1100 rockers arent the same width.
            The opening and closing ramps on them are asymmetrical.

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