I have freed up stuck valves in the past without removing the heads. You can remove the valve covers, the rocker arms, the valve spring keepers, the valve springs and the seals. Crank the engine till the piston is at top dead center. You can use compressed air to keep the valves closed. Using any of the solvents that will disolve the varnish on the valve stems, work the valve up and down untill it feels free. Reassemble. The piston at the TDC will prevent the valve from falling all the way into the cylinder. The compressed air will hold the valve closed while you reassemble the seals, springs and keepers. Harley (
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