A few engine questions??? CG

[Bill Hilly]

As many know,I had a cheap roller cam follower loose it's bearings, and at minimum it's damaged the timing gears. I know because I can see the cam gear, and so I pretty much know the one on the crank has to be damaged. I have been looking at videos on YouTube, and there are several that show how to change the timing gear on the crank, but they are all in the language of India. They use a special puller specifically for the CG( a helical timing gear puller), that requires tearing it down no farther than removing the flywheel.It's about $20.00 on Amazon, and cheaper from AliExpress. My two
concerns are. Wondering if my transmission gears could be chewed up. And while I can't really understand what they are saying, it appears that they just "eyeball" the timing mark on the crank gear, by using the flywheel keyway for reference. The crank gear hasn't got a slot for a key. The crank gear goes back in the crank a couple of inches past the flywheel keyway. How is timing precision maintained ? The motor that's on my Hawk now runs great, and hasn't really got a lot of miles on it , and keeps the oil good and clean. I hate to tear it apart, and put my 70 mm jug, and home ported head on it. I ordered another cam, just because it was cheap, and because of the fact that when my roller follower lost it's bearings, it allowed the non rolling part of the follower to run against the cam. My plan would be to drain all the oil, clean the oil screen, and maybe try flushing the inside of the motor with kerosene ( don't know if that's a good idea though)... What are your thoughts?? If there's a good chance of the transmission gears being damaged, I don't want to fool with it. Also any opinions on the timing of the crank gear would be appreciated. Thanks

I am adding this video that shows what I mean on the crank gear. You will probably want to fast forward through the first 6 minutes.