Single cylinder and multi-cylinder balancing

Discussion in 'General Questions' started by Fabian, Jul 3, 2012.

  1. Fabian

    Fabian Well-Known Member

    I've seen this topic covered so many times yet there has never been any formal and in depth technical information presented, that takes out the mystery and inserts maths.

    Video tutorial:

    Single-Cylinder Engine Balancing:

    V & Radial Engine Balancing:

    In-line Engine Balancing:

    Last edited by a moderator: Dec 15, 2015

  2. Lee_K

    Lee_K Member

    I remember studying this very subject in college (44 years ago). I never did get a good grip on balancing reciprocating masses. But I know single cylinder engines can not be perfectly balanced at all speeds, engineering always involves compromise. Good engines designed and built by good engineers have been through this analysis. Good engines will still shake, but someone has put lots of effort into getting it under control.

    Many years ago I had a 350 single cylinder Ducati motorcycle. It vibrated so bad between 4000 and 5000 rpm that you could not stand it. Rev it faster or slower and it was OK. They could have done a lot better with this engine.
  3. Fabian

    Fabian Well-Known Member

    That's why you add another cylinder to a single cylinder engine at 90 degrees - why won't the Chinese learn this simple lesson and manufacture a 90 degree v-twin for our bicycles, though i wouldn't mind seeing a parallel twin cylinder bicycle engine with a non planar crankshaft i.e. half cruciform crankshaft arrangement, like a Yamaha TRX 850.
  4. LewieBike

    LewieBike New Member

    I owned a ducati 250 bevelhead, it was pretty smooth for a single 4 stroke of it's vintage.
  5. jaguar

    jaguar Well-Known Member

    when I clicked to see the first video I was presented with the words "this video does not exist"
  6. Fabian

    Fabian Well-Known Member

    The link has changed:

    Last edited by a moderator: Dec 15, 2015