Go easy on that grease killer! It will work into the big gear after a few miles. If you get too much on them, it will get in the clutch then you'll have to clean it out.

Some bicycle motors whine more than others. I had one that made more noise than the other two put together.

As for your gear, that looks about normal to me. I just took one of mine apart to check it and it looks the same as yours.

Now, interesting story, even though the engine I just took apart has well over 500 miles on it, there is grease I put on the gears when I put it together at 0 miles and it is still in between the gear teeth like the engine has never been turned over! I guess thats the precise tolerances we are dealing with here!

__________________
If it ain't broke, and you mess with it long enough, it will be.