A small group of people dole out extrajudicial punishment to evildoers. A gimmick is that one of them is a judge who, when the robe comes off, is a badass motorcycle rider. It, iirc, was pretty bad.
There was Hardcastle and McCormick. Hardcastle was a judge who retired and decided to go after people he thought were guilty but had escaped on legal technicalities.
But Brian Keith played the judge and I don’t think he rode a motorcycle.
This sounds like a movie called The Star Chamber.
Thanks TOWP- I think that’s it.