The unbalance of the crank

[Janne]

I made a crank holder to be able to hold the crank while spinning it to feel the unbalance first hand.

Just a short video of it:

[Janne]

Another video of testing the static balance of the crank with a dummy piston. The dummy piston is a little bit smaller.

[Roostius_Maximus]

cool

[NightBiker07]

the whole assembly must be balanced. meaning using the same piston you will be running. otherwise the tests and balancing will be worthless.

[Janne]

the whole assembly must be balanced. meaning using the same piston you will be running. otherwise the tests and balancing will be worthless.

No.

Testing in the first movie was done with the complete piston weight to get a feel for how much it is vibrating,
but the static balancing was not done with the complete piston weight.

With 100% balance factor the assembly would be unrideable. No vibrations in vertical, but enormous in horizontal.
I did go for 50% balance factor, using the same piston weight I am running in the calculations, which is maybe what you meant.

This is how I measured the balance factor from the factory:



...and weighted the nuts:

[Janne]

The small end weight:

[Kuma]

In your second video, I noticed your shirt sleeve looked a little tattered, just wondering if that happened while making the first vid

[100hp honda]

cool videos. you got ozzy in sweden . any chance you can make a day trip over to austria and tell them fools at ktm we need another big 2stroke in the line up

[Janne]

In your second video, I noticed your shirt sleeve looked a little tattered, just wondering if that happened while making the first vid

No, it's an old riding shirt and I used to cut the sleeves to prevent armpump.