I done cocked up...

[Andre3127]

There is no position where at least 1 valve isn't open.

Use the dowel trick to move the pistons all down equal to each other. BBQ skewers would work. Just make them all the same length, stick on in each spark plug hole and turn the crank until the tops of all of them line up. Then rotate the cam gear until the marks line up, then finally rotate the crank until it lines up.

At least on 84-86 ETA heads, there is a cam position where all the valves can be closed once you slide the rockers over to one side.

It seems like you would be able to check for a bent valve by closing all valves (with this method) and filling the cylinder with air while listening through the intake and exhaust ports for air. If you find any signs of a bent valve, don't think about running it. You may very well burn up a seat and that will require machine work. You should be able to rent a 14mm spark plug air adapter from a leakdown tester that can be rented from Autozone.

[digger]

to slide all the rockers to the side safely you need to rotate the cam