That cover has 2 dowel pins, it supports the kicker while you kick, when the aluminum stars to wear, the seal leaks. For some reason I remember only a needle bearing on the opposing shaft that doesn't get much force (going off memory here)
The gasket can be cut but MUST be the same thickness or the cover tightened up will bind, thats why guys who use silicone have such an issue with them.
Line up the 2 dots on the gears.
Use the corner of a sandwhich bag with grease or oil on it to slide past the splines whether you install the seal on or off the trike, just to protect it.
It's a very easy seal to change, just the tiny cover, I grease and clean all my dowel pins so stuff comes apart again.
Lots of guys change the seal with the cover on, but getting it off without damaging the cover or shaft can be a skill and having something to just touch the outer portion of the seal can be a pain, too small and it dents the seal during install.
EDIT - Thats why I try and get both the Clymer and Shop manual, they differ a bit and you can learn from both of them.
How do you think I got decent at fixing things? Reading every tech section in Dirt Bike, Dirt Rider and owning 25 dirt bikes and 10 trikes over the years. A Yamaha can help you fix a Honda, it's all in what your mind retains......
If my alcohol soaked brain and previous drug use retained it, surely the rest of you can
All our government does is distract us while they steal from us, misspend our tax $ and ruin our country