bb, Keith,
Ducati ran across the same questions in designing their 'supermono',
essentially a 90deg. v-twin with the rear cylinder off to give a single whose
crank still 'believes' it is a twin.
They thought of leaving a piston but the pumping and friction losses were not
good.
They settled on a balance 'arm' like a small con-rod. It's 'big end' rode on
the standard rod's small end, and it pivoted on the cases to give the
equivalent weight to the other piston.
Their race only version cost $30k; I'm going to build my own; not as fast but a
lot cheaper ;-)
Not practical on an 8 unless it was cut up for it. Other options might be a
carved up 'slipper'/1-ring piston, maybe even with the top opened up to save on
pumping losses. You could add the weight back on the wrist pin etc.
How different would that be from just a weight clamped right to the journal?
Your up and down balance would work but you would introduce a side-to-side
component; the difference between the total and the stock bottom end.
Cheers,
Rick
bernien2 wrote:
> Keith , do an extra piston if you are expecting them to get religious. Also
>you can go lighter, not heavier, and be ok.
> Rich, never tried a v7. are you running with nothing there at all? No rod
>thrust problems. I think if I was going to try doing this I'd start by making
>a ring of al that would bolt to the crank and-- no i wouldn't. i'll have to
>think about that. if it's not hurting brngs or breaking the crank or snout,
>maybe "nothing to do with any plan" is the best plan. maybe i'll experiment
>and get back to you when i really have tried it and know something. bb
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