Solo,
Easy to remove the governor - disconnect the governor arm from the top of the engine - OR
1. Remove the side cover no gasket required except for "gray silicone" to re-assemble.
2. Notice on the side cover you'll see a hole where the governor shaft is visible, take a drift punch and...
you can get a cam i have this one in my motor http://www.smallengineperformance.com.au/index.php?page=shop.product_details&flypage=vmj_ace.tpl&product_id=607&category_id=42&option=com_virtuemart&Itemid=12 just not alot parts for the ex17 more for the ex21,ex21 and shipping does not take long...
robin subaru parts thats ware i got a cam for my ex21 motor http://www.smallengineperformance.com.au/index.php?page=shop.browse&category_id=19&option=com_virtuemart&Itemid=12&vmcchk=1&Itemid=12