HELP!!!!! 82 CB750 top end rebuild

[UselessGoose]

So over the weekend I decided to take my engine apart and rebuild the pistons for the first time.  I had a Clymer Manual and the internet handy as I worked my way through the process and everything was going great up until I started putting the exhaust camshaft back together.  While trying to get the exhaust chain over it's sprocket I attempted to turn the crankshaft to help slide the chain onto it's sprocket (Like you would a bike chain).  How ever now the crankshaft is stuck! (even when I hold tension on the exhaust chain)  I can't move it either way.  
- Piston 1 and 4 are not TDC neither are 2 and 3.
- I took the Camshaft out and peered into the crankcase and couldn't see anything disrupting the crank or chains.
- Put the bike into Neutral
-Oiled the pistons and cylinders as I put everything back together and sprayed some lube through the sparkplug holes to see if that would help but so far nope.

It's 10:30 on a Monday night.  Right now all I can think to do is start ripping everything apart again to try and find the issue but I thought I would try here and give it a day before getting too carried away!

Cheers
Goose!

Edited:

[TOOLS1]

Slack in the cam chain has most likely balled up around the sprocket on the crank, and is binding the crank from spinning (try rocking the crank back and forth, while pulling on the cam chain,) or you dropped something down in there.
TOOLS

[UselessGoose]

Ill give it a go again today but the crankshaft wouldn't move at all last night and when I shine a light inside the chain appears to run smoothly around the sprocket on the crank!  I am also 99.99999% sure I have kept everything not supposed to be in there out!

[UselessGoose]

So I fiddled around with it again this morning still no change!  If those are the two best suggestions I am gonna have to put my cover all back on and dive back into it!

[UselessGoose]

It appears that the pistons are too tight in there cylinders???? When I loosen the cylinder head cap nuts I can turn the crank shaft but the whole block moves??? I checked the rings again and the appear the be correct for the bike

[TOOLS1]

I doubt the rings are too tight, did you check the gap before installing them? Also it is normal for the cylinder block to move with the pistons when it is not bolted down.
TOOLS

[UselessGoose]

I just checked the gap with the rings.  I didn't use a feeler gauge.  But everything seemed to be smooth no troubles on piston assembly.  I figured the block would move from the friction caused by the pistons.  It's more that when everything is bolted down I can't turn the drive shaft but as soon as I start taking things apart the whole block moves which makes me think it is not the chain but something causing friction amongst the pistons themselves.

I am in the middle of taking the cylinder block off now.  I took just the cylinder head off earlier.  There seems to be a lot more friction than the first time I did it!

[UselessGoose]

Like I am entering the pry bar stage