Manuals are always handy to have, but if one always went with only the “Factory” manual on a lot of things motoring related we’d be pretty screwed. Bentley and Haynes come to mind.
Chris your argument is equally weak when it comes to tolerances unless the manual you are talking about refers to a cr125 running an R4 or SK-1 pipe, 38mm carb (pumparound, magic can or GFS), bolted on a kart running on asphalt getting the absolute piss revved out of it 30+ times a lap. Yeah, its neat to have when you need to assemble it, no doubt but it’s hardly the mecca of information that you claim it is.
I’m pretty sure the CR125 manual you hold in such high regard was written (or approved, whatever) by Honda with no consideration for use in a shifter kart application.
By your own logic, we should be looking for a manual from Honda or HPD that is specific to a CR125 “Stock Moto” in a kart racing application. If you have one, post a link, otherwise drop it.
Homologation sheets are not a replacement for a manual, however Tom does have some good guides on his website that apply to most ICC\KZ motors. Pretty sure there’s a few videos out there on youtube too.
P.S. We all get you are a badass driver and motor builder.