Installing Carby's

I have done my own valve guides for lots of years. You do need to know what you are doing and make sure you have cleaned all traces of carbon from the guide, heat the head and press the guide from the head rather than drive it. If you have access to machine tools , then cutting the guide out is even better. Of course, after installing the new guide the valve will now have to be re-lapped to assure a good seal.
If you are trying to extract the last bit of power, then send the head to a well-equipped Norton specialist (and have it flowed while he has it).
I'm sure Cookie's method is very precise, but Norton motors are more like lawn mowers than airplane engines :lol:

We used to dry ice the guides before install and gently heat the head in an oven.

Is that reccomended these days Ron?

Can't say what is "recommended", but I heat the head to 300-325F in an oven (not a kitchen oven!) to remove and install the guides. I toss the the guides in the freezer for about 10 minutes prior to installation. I draw the guides in using a factory style tool (wearing heatproof gloves).

What is flowing the valves? The guys at the shop said that the guides were not reamed (my word not theirs) and were too tight on the valve stems. He mentioned that it could have siezed the valves and that they appear approx 0.001 thou vice 0.003 thou.

Ref the lawn-mower allusion, is it required to bore the guides out to match the valves?

Thanks for the great info...next time I amy even try it myself...