[blade625]

I pulled my heads to clean them up and lap the valves [I am not too bright. I raced this bike for two seasons on 110 race gas, and never fogged the motor after the weekends, resulting in a fair bit of corrosion]

anyhow, I decided to check the guides with a bore guage. Everything checked out except for the H cyl. exhaust guide. Max clearance is spec'd at .00314
The guide seems to have a bit of taper. At the rocker end I have .0012 [well within spec.] but at the seat end I have .005 which is well out.

My questions:

1]Is this guide considered toast?

2]If I replace this guide, do I really have to heat the head to 365deg to drift it out? And then heat it again, and freeze the new guide in dry ice prior to driving it in? [my, thus far, very tolerant wife is going to love me being in the kitchen, cooking motorcyle parts in the same oven that she puts roasts and turkeys in....]

3]can you get guides that are bored to the correct size? or do you have to bore them out yourself? valve stem right now is 7.97mm [.314] and looks fine.

4]Is this something that is generally better left to a machine shop that does head work?