Bad Oe Cam Chain Tensioner??

Hello, just checked my valves on '13 TE310R because it was starting to sound like a diesel. I recently bought the bike so I have been busy going through it and finding resources for it.

When I pulled the head off, I notices my cam chain is to loose. I don't know how tight it is supposed to be but it is definitely to loose. My valves are in spec so the noise must be the chain. It has signs of wear on top of the teeth.

I can get a new OE tensioner but does anyone know of an aftermarket one that is manually adjustable?

Also, the thermostat was removed so there is unnecessary hosing in front of the engine, would the 250's hose that is made without the hose for the thermostat fit the 310 radiator and water pump inlet like it was factory without the thermostat?