Navigator chain sprocket

A puller! What have you tried so far?

dan

hello The gearbox sprocket  should come way easy  once the tap is flated out and undo the left-hand nut  then it comes way easy  mine did and it had been stud for 35 odd years  no need for hammers with me its that easy    yours  anna j    

Left Hand Thread on the main sprocket - once the tabs are pushed back.

If the engine is still on the bike & the chain is connected, you could put it in 4th gear and stand on the brake - or if the gearbox is apart, you could try a stout piece of wood through the spokes onto the swing arm.

Or if the chain is not there ary more, you could wrap a chain around the sprocket until it binds - but beware of damaging the breather pipe above it (on an engine numbered below 106838 - the breather got moved after that number).