Hi all, this is a plea for advice. I'm trying to change the primary chain on my Navigator, but I'm completely stuck with removing the engine sprocket from the crankshaft. I've left it under as much tension as I dare, (using the puller that the OC sell, as picture) but despite several goes with a (small) blowtorch, and blows with a copper block and hammer it seems nowhere near breaking its hold on the taper. I've followed procedures I've read from earlier disussions of this on here - I just wondered if there's anything else to try, or is it just 'more heat and more force?'.