Crank balancing question

CanukNortonNut said:

I believe that there were three holes but I am at work now so need to recheck when I get back home in a couple of days.
I'll report back.

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Thanks !!

fiatfan said:

My -73 850 flywheel, holes everywhere but none deep enough to put a rod in. So it was back to the old "rod through the rods" method..... worked fine. Not sure, but it seems the holes in the wide side is filled up with something, lead? A bit strange since there are holes in the narrow part as well. I mean they could have skipped those and not having to fill in the other holes, I don´t get this.
View attachment 83412View attachment 83413

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You would want to hope that is not lead and taper punched in some effort to expand the plugs (if that is what they are) to hold them in place.
That seems odd as surely (taking note of the off side drilled dimples) adding weight to the counterweight is for a heavier piston if it can not be achieved with lighter piston pins.
You might wonder what the BF is being Commando.
Removal of counterweight for lighter pistons depending on intended BF.

Given the shape of the multi piece Commando crankshaft, dynamic might not be as important with the cheeks being similar and a fairly uniform sludge trap oil feed cavity.

RatedSpeed said:

Thanks !!

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Looks like it has 4 holes plus one (shallow) kitty corner of the heavy side. So I'm not sure what to make of it now. Looks like this crank has been balance to a B/F of ??%?? who knows.
This may not be original from factory.
Regards,
T

CanukNortonNut said:

Looks like it has 4 holes plus one (shallow) kitty corner of the heavy side. So I'm not sure what to make of it now. Looks like this crank has been balance to a B/F of ??%?? who knows.
This may not be original from factory.
Regards,
T

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Atlas crank ?

I have two 850 Mk2A cranks. Both have only one inch diameter hole bored into the counterweight.

The original crankshaft from my 850 Mk2A has 3 uniformly spaced balance holes in the counterweight and no reason to think the cases had been split before I did so.


This 1974 850 cranks has 5 holes.



This 1973 850 crank has three but not uniform and offset radially.




Two 1971 750 cranks, one with 5 holes, 4 holes in the counterweight lower and 1 single hole around 80 degrees rotated to those, the other with 6 uniform spaced holes with the rotor key locations the same on both.

Did the weight of the pistons change, I do not know.

Hi all,
Can you supply the width of these flywheels if they're on the bench and the casting numbers if visible?

Mike