agree with sd,this is not a gear that stick for no reason but can crack at center at grubscrew as you say it make grinding noise.just remember timing will be affected if you replace this gear.best is to spray with parrafin or non chlorinated cleaning solvent to see problem happy hunting and happy new year
johan
January 2013
Question is what is sticking it, They do not just stick. Check the gears and shafts connected to it. Possibly grub screw in middle of gear has come loose. check them all, does not stick for no reason
SD
January 2013
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