Counterboring Cylinder Head Valve Seats

It's been a long time since I did bike stuff, but hard seats- check SB International for the interference fit. I remember it being .002 on cast iron and .004 for aluminum, but my memory is not perfect. If it already has hard seats, zap it with a quick weld and it will shrink enough for easy removal. I know a lot of people that hammer them in, but I use a small press. Then cut the seats with (I think you posted a Neway) or hit them with stones. The old Sioux 1700 was a straight end stone driver and worked well for angled valves (hemi, bikes). The 1710 is the angle head driver. I personally prefer Sioux, but Kwik Way is a good choice as well. All of this assumes the guides are in decent shape. Looking at what you have, I think the only thing you will want is a quick way to mount the heads from moving, no mill really is needed.
 
In aircraft school we heated the seat/head area with oxy/acetylene rose bud and checked the temp with temple sticks. They had a couple of homemade gadgets that were basically a tube with a rod down the middle with a handle and flat washers that squeezed a very dense sponge that was soaked in a bucket of ice water. Got the head to temp and jammed the sponge squeezer into the valve seat and squeezed the handle and popped the seat right out. Cleaned and checked the seat to head fit and reversed with the seat frozen and head heated jammed it back in. Don’t remember needing a BFH but that was 40yrs ago.
 
Nesse1 said:
I use Neway cutters too, but if doing a lot of seats, I'd go to stones like Kwik-Way.
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I used Neway too. I dont know how big the valve stems are on the OP’s but I learned the hard way if you can’t find a way to hold the guide vertical when using a seat grinder the weight of the motor will pull the stone and grind the seat off center. I was taught to always Prussian blue seat/valve and just about ruined a Honda head with a Souix setup I had that were all solid pilots and ball bearing mandrel that were very close to unused. YMMV
 
C-Bag said:
I used Neway too. I dont know how big the valve stems are on the OP’s but I learned the hard way if you can’t find a way to hold the guide vertical when using a seat grinder the weight of the motor will pull the stone and grind the seat off center. I was taught to always Prussian blue seat/valve and just about ruined a Honda head with a Souix setup I had that were all solid pilots and ball bearing mandrel that were very close to unused. YMMV
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That's the most frustrating part for me. I have no access to factory tools and such and since retirement no access to a mill. But setting up the head was a real pain; getting the angles right so everything lined up as the factory's seats were.
 
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