Cog belt toothed pulley

[Jezza-7]

Im just replacing mine as i speak and want to know which was the cog goes on the main pulley drive. The top cog has a guide rail that is closest to the charger and the one on the main drive had the guide rail away from the charger. Will get a pic to be more clear.

[PeteG40]

the main pulley one has a big keyway, the top has a small one - but doesnt need to come off.  If it has then you need to loctite the bolt on.

guide on the inside on top one, outside on bottom - as you described

[Jezza-7]

Like this



Not this



Top ones fine