with a std mini crank there is a lot of comments about the std crank having poor balance.
So what is crank shaft balance. Just take the crank it's self. Now we have 4 big ends [two pairs exactly 180 deg opposite each other] and 4 webs[two end ones and two center ones ] and the web shape is a mirror image.
So this is how you get a "near" perfect std crank balanced. All the webs need to be machined exactly from the centerline of the crank, and each web must be exactly the same dimensions.
Here is a crank that is completely machined to a tolerance of + or -- .003"
every angle is the same and every opposing web is the same.




This is the "out of balance"factor with a std crank. The casting/forging is not accurate and the original machining does not allow for this .
Just as a matter of interest some of the webs were about .160" different on opposite sides.

This is the 998 crank going into my 1275 block and the crank gear tail has been machined down to 37mm from 38mm and the crank gear runs on needle roller bearings with a rear seal instead of brass bushes and oil leaks. The OD of the bearings is 42mm[same dia. as the inside of the gear] and are 17mm wide.
As the cranks are EN16T material , then this material can be induction hardened.

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