Engine assembly and how an engine works.

Discussion in 'UK Motorcycles' started by Cab, Nov 1, 2006.

  1. Cab

    Cab Guest

    Shamelessly nicked from frm:

    So what, it's a cage, but interesting and well done, IMO.

    On frm, the concensus is that the engine in the first clip is that of a
    BMW. Confirmation anyone?
    Cab, Nov 1, 2006
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  2. Brilliant! Haynes manuals should be like the first one - type in, for
    example, "Cambelt change" and it shows you exactly what to do.

    Mungo \Two Sheds\ Toadfoot, Nov 1, 2006
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  3. Cab

    Ken Guest

    Wonder if it provides info on changing gear box bearings without stripping
    the motor? If not then maybe TOG should get in touch and offer his
    "expertise" to cover this topic?

    Ken, Nov 1, 2006
  4. Cab

    Tosspot Guest

    Errrmmmm, very dumb question, why are the cylinders spaced 180 apart and
    not 90? I kind of had it in my head that thats how they were.
    Tosspot, Nov 1, 2006
  5. Bloody good, is that.
    No idea....
    The Older Gentleman, Nov 1, 2006
  6. Cab

    Berty Guest


    Some are at 90.
    Berty, Nov 1, 2006
  7. Cab

    Eiron Guest

    For balance and equal firing intervals. They're all like that.
    You're thinking of half a V8.
    Eiron, Nov 1, 2006
  8. Dunno, but I've got the original screensaver of that at work somewhere. I'll
    see if I can dig it out, it may give a clue.
    Brownz \(Mobile\), Nov 1, 2006
  9. Cab

    Tosspot Guest

    That's pretty much what I thought, but for the life of me I can't think
    why it improves balance. Cheers anyway, I'll google it in my free time.

    <pauses> and inline 6?
    Tosspot, Nov 2, 2006
  10. Cab

    p-Brane Guest

    View a single-cylinder engine from the front (or rear). Crank goes around,
    piston and rod goes up and down. The crank has a counterweight that
    balances the mass of the piston and rod (and some of the mass of the crank
    itself) at TDC and BDC. But at all other angles, the counterweight is
    swinging to the left or to the right of centre, with insufficient opposing
    mass to balance it. Add another cylinder, 180 degrees from the first. Now
    the counterweights balance each other out. But the cylinders (obviously)
    don't lie in the same plane, so there's a 'couple', which attempts to make
    each end of the crankshaft (and hence the engine) trace out a cone. So now
    add another two cyliners, just like the first pair, arranged 0-180-180-0.
    Now the couples balance each other out.

    Perfect balance? Not quite. Although the four-cylinder 0-180-180-0 engine
    has good primary balance, there is a second-harmonic vibration, which is
    caused by the fact that the pistons' vertical motion is not harmonic (i.e.,
    the vertical displacement of the piston, when plotted against crank-angle,
    is not a sine wave). The engine does not have perfect secondary balance.
    One way to reduce this problem is with a harmonic balancer-shaft (or
    shafts), geared to spin at twice the rate of the crank.

    Has perfect primary and secondary balance (with a 0-240-120-120-240-0
    p-Brane, Nov 4, 2006
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