Minor Threat

Lot of machine shops just shim the guides if they're that worn.

rudebwoy

as ya'll know my complaints of incompetent German shops here I have not many choices, and when I find someone who partially know what they are doing it will cost more than the complete motor worth to do it.
so I have no choice but to do it myself.

Ravage70

I wouldnt touch the guides, they very rarely need replacing

Minor Threat

It's one of those things that is hard to do at first, but gets easier the more you do it. I would suggest practicing on a junker head.