And that is the biggest issue with the Roids. Just a little cleanliness and attention to detail during assembly could result in a vastly improved final product.
As for your cam gear, what kind of idler gear are your running, Bronze or iron? What is your backlash between crank and idler and between idler and cam? I measure the idler gear backlash by wedging the flywheel in place and use a rod to a dial indicator and wiggle the idler gear. To measure cam gear backlash, I roll the engine to a point where the cams are not loaded and jam the crank-idler gear by rolling a rag into the gear mesh. Then I use a longer rod to reach into the cam gear teeth and press against the dial indicator while i rock the cam gear.
Large backlash numbers(greater than .010"-.015") are going to increase the hammering effect felt by the gear teeth. The cam gear is also under quite a bit of stress as it takes a good bit of torque to roll the cam and IP lobes up under their respective valve and pump loads. Depending where the partial tooth is in relation to the cam lobe loads, that tooth may not have any real load and may run forever without problems. But if not, a gear failure could cause other more serious problems, such as gear damage to the crankshaft gear... My Motto is: When in doubt, change it out.