Michael’s engine rebuild

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This topic contains 51 replies, has 7 voices, and was last updated by  jett 3 years, 4 months ago.

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    Grabbed the Dremel, an Edding and six hours to achieve this:



    Will post final pics of what I have done.
    These are pics during the work process.



    Well, this was sitting in the garage unattended for a long time.

    After checking what would be the next steps I finally decided to get some new or modified camshafts !

    There is a company called Megacycle in the US that do that modification, but I have found a company called CAMPRO in Germany and they offer the same modifications.
    Lower Price, lower shipping cost, no tax.

    Will send the complete cylinder head incl. additional outlet camshaft to be modified as inlet camshaft (2 mm more lift)!

    They offer even some other work I was looking for, e.g. modification of the combustion chamber to match the big bore pistons (86mm).

    To prepare for further progress I was told to use new valves, as the history of the existing valves is unknown (maybe overheated some time in the past) and there is a risk of using them in this “special” engine.

    Ok, bought NOS valves, 2x inlet and 4x outlet, to be prepared 😉
    Outlet valves are more critical in regards to overheating as the inlet ones, of course.

    Will prepare to ship that stuff to CAMPRO within the next few weeks and then they can do their work.

    Cheers, Michael



    Did you expect that the weight of the inlet and outlet valve is close to be identical, even with the inlet valve having a larger head diameter ?
    About 80 grams each.
    BTW: Valve stem diameter is 8 mm for both valves, which is very solid.

    Did you know, that the exhaust valve is made from two different materials ?
    Tested it with a ball-shaped magnet.
    Head isn’t magnetic, while shaft is.
    Magnet sitting at the “border line” between these two materials.



    I was not aware of either facts Michael. I would guess that the different materials are required for heat issues but maybe it is to keep the weights balanced?



    This is fascinating. Amazing work Michael!




    first off – thanx for sharing your build and with superb pix !! Better than a Haynes manual.

    Of course, this is very helpful for my own little Glemseck project as I am completely new to the KZ 750 engine.

    re: valves / different materials.

    This is common practice with Hi-Po US V8 engines. The head area is an alloy to protect against heat, whilst the stem does not require such treatment .

    It was also used way back on my Norton International engines. The exhaust valves [ Manx and Inter ] were sodium filled to combat extreme heat.

    I remember “clipping” an exhaust valve and it cost me a week’s wages to replace it [ 1963 ] ! The change in material was obvious on the new valves, which were also “swirl” polished in the head area.

    Thanx again for sharing.

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