if it is still too tight after removing the tensioner, look down the front case with a torch and see if the chain has jammed between the tensioner guide and crank sprocket, happened to me a few times, just have to wiggle the chain about a little. Also have you torqued down the head bolts all the way?
Lets go find that Hotdog tree I planted
Lowered EF Futura
Black Steelies ( too cheap to buy proper mags )