Dang.. Gw's right.. You will have to pull the right side case off P5200.. I'd been thinking the chain was on the left..

Just reading all the posts since you found the chain, no a whole lot to add except also curious why it came off , is the tensioner in tact. From what I remember you can get the chain back on like mech said by taking the gear off getting it back on the gear and manipulating it into place, hoping you have enough fingers to hold it in place hold the bolt, start the bolt at the same time, I would probably do that first just to see what's going on . I think to put a new chain on that engine you have to pull the clutch and the oil pump to get it on the crank.

No.

I thin it's possible to get a new chain on, I've always been able to get them off with the heads on. You let the chain dangle down by the crank, then bend/fold a bit at the bottom forwards, swing that short leg out and around the end of the crank and on over it. The special tool... I've never used one on anything.. I don't know that I've seen that particular type of tensioner but most can be reset somehow using pliers or screwdriver or a bit of wire.. Have a play with it.. It gets retracted to fit it, then once it's released there should be a spring that pushes the plunger out, and a ratchet to prevent it going back in. Check the ratchet mechanism very carefully for wear. It might have slipped and caused the problem, and the wear might only be in one place, the place it was sitting with the old chain and slippers in there. A new chain might have it sitting in a better place, but you don't want it to slip again later after the chains stretched a little .

Did you take the top cover off where you can see the cam gear chain and valves or is that what's stuck.

You need to check the valves aren't leaking after you get the cam out.. They can get bent when a chain comes off.. on some vehicles. Neither the cam nor the chain will be holding the cam/head cover on.. It will just be the dowels and the sealant.. if you are sure you got all the bolts out..

If you are having trouble getting the head off maybe the chain just jumped off the cam gear.

The cam cover is that top piece of/on the head assembly, it has the valve covers bolted to it. They might call it a head cover or something.. There are a couple of dowels locating the cam cover, they will be tight probably and hindering the cover lifting off. You might have to find somewhere to lever the cover up a little..

To just change the chain alone I think you'll be able to take the cam cover off, cam out, and the side cover and stator flywheel etc off, then by rotating the chain when looking from above, that is, swing the front throw of chain out away from the bike, so it'll swing around the end of the crank, and then haul it upwards. If you need to change the timing chain and slipper I think it may be necessary to take the head off.

I just assumed from your last post about replacing the chain it was off, I would say if the valves aren't moving when you roll over the engine it is either off or broken, did you pull the inspection cover to see if it was there.

Not too bad, you have to pull the head to be able to fish the broken chain out of the crankcase

Yup.. Sure sounds like it. Once you take the valve/cam cover off you will see if the chain's off or broken.