Adjustable clutch weights ?

[Pstn head]

I saw somewhere that the primary clutch arms or weights can be adjusted by screwing in a longer or shorter Allen bolt to add or subtract weight to primary clutch to increase or decrease engine rpm. I would like to know where I could get them from. Please excuse my terminology I'm not sure exactly what the parts are called.

 

[kviper]

Ulmer Racing!
He sells STM weight's. Easy to load and adjust.

 

[Pstn head]

Excellent thanks