Thinking back, maybe they screwed up the 3 angles the seats are cut to. Exhaust and Inlet a bit different as well. I've heard of a shop making all 45 degrees on a bike engine. To correct that on already cut deep seats might indeed be close to impossible.
I have no idea what machine they have, but there is a shop around Vancouver where they apparently use a 1.5 million machine which after settings cuts all the seats at once. No idea how it works as I never asked, but that's what I heard from the guy who was assisting them and the technician who came to set it up.
This is how the pro's do it. This Sunnen machine is a newer version of the machine available in Peterborough where I get my head work done. All the same principals. It's a multi angled cutter head with a selectable pilot which fits the valve guides. When the operator wants to line up the pilot to the guide, he steps on a pedal which floats the head on an air deck. when the pilot slides freely in and out of the guide, the operator removes his foor from the air float switch, then plunges the cutter down till it hits a hard stop which was predetermined. Seat cut. Float the deck, move the cylinder head to the next hole and repeat.
This 3.45 minute video shows 8 seats being set up and cut in real time. Damned near idiot proof.
That's quick! They charge $20 per seat here. The instructor told me he can do it by hand for $10. I might take him up on it.
I remember when we talked about this at the time when doing my engine. I kind of regret not purchasing a set of cutters at the time. It would last for many heads. He has an adjustable one. He said it cost about 7 - 8 hundred bucks. That would be handy! Although I prefer one per each angle separate. Feels like I'd have more control.
But I imagine if it's a solid product, it will be as solid for all those different settings.
I have finished shimming the valves on the z1300 head. Looks like you have a head you can use.
I had instructed the engineer to re-cut the valve seats and re-profile the valve heads so that there is a 1.00 contact area on both the valve head and seat.
These were also lapped in so to seal properly and tested on a vacuum machine.
We had a mix of contact area from 1.00mm to 2.5mm and a lot of the contact faces were pitted.
As you know the problem was the valves had been cut to far into the head to start with.
After the seats and heads were re-faced we had 0.30mm ground off the valve stem.
This has left you with new valve seat cuts re-faced valve heads with ground stems.
0.05-0.15 Inlet valves-shim size- clearance
1- 2.20 - 0.10mm
2- 2.25 - 0.10mm
3- 2.45 - 0.10mm
4- 2.45 - 0.10mm
5- 2.35 - 0.10mm
6- 2.35 - 0.10mm
After the work on the head and valves we have managed to bring the head back to a usable range.
Now I just need to not screw it up!
Updates will continue as I go along, starting this weekend as the wife will be away for a day or two.