as per the shop manual I have tried to remove the pulley nut using both the rattle gun & a breaker bar can you perhaps shed some light on what may be preventing me from breaking it free & before you ask the pulley itself is stamped right hand thread

 

The nuts sometimes weld themselves to the pulley. I busted breaker bars trying to get them loose. When they don't pup loose, it's easier to cut the nut as much as you can with a dremel then chisel the slot a bit and try again with a breaker.. Nut will split and come off.

 

What year and model?

I think you're right. The sprocket nut is conventional righty-tighty. It's the mainshaft nut, that abutts the clutch, farther outborad that is reverse thread.

Three things:
1) 3/4" Impact air gun 1000ft lbs from Harbor Freight for like $100 puts down all rebellions.
2) Try soaking overnight with PB blaster.
3) preheat with propane (or map gas) torch.

 

Good stuff except that, pre 07 (and 06 Dynas) are left hand threads..

 

make sure you have backup as any slack will lessen the blows and could damage internal stuff. if original, might have to heat it a tad to loosen the lock compound.

 

Heat it and hit it with the impact gun.Heat and beat, heat and beat.