450WR clutch side disassembly question

My '72 450WR is smoking heavily and running fat--thinking the clutch-side crank seal is bad. I don't have a manual for a 5-speed and just want to check a couple things:
1. I assume the threads on that side of the crank will be conventional right-hand; correct?
2. From a picture I found, it looks like the drive gear can be removed without taking off the clutch. Correct? If not, any special tricks/tools/left-hand threads necessary for that?
3. Does the drive gear put up much of a fight getting it off?
4. Does anyone have the metric dimensions of the necessary seal?

THANKS! I like to have most of the headscratching and preparation done before getting into the job, so it all goes smoothly.

You do realize that the seal is inboard of the bearing.This means you have to split the cases to replace the clutch side crank seal.

Ahhh, rats! That's not what I wanted to hear, but it IS why I posted the question. Thanks for saving me the frustration of getting in there and realizing what really had to happen. Now I can at least plan appropriately. Thanks for the info.

The clutch side crank end nut is right hand threads. You will have to split the cases to get to the main seal that is leaking. You can purchase a case splitting tool on Ebay for $65. Go slow and take a lot of pictures of how things came apart. Your 72 is a five-speed. When you assemble, make sure the transmission is in 3rd gear and two teeth of the stepfeeder gear are visible under the shifting barrel (to the left), and one tooth is visible to the right. Otherwise it will get stuck in gear and you will have to do the job over again.

Notice to the left of the spring clip, two teeth are visible under the shifting barrel to the left, and one tooth on the right (and your detent has to be in the 3rd gear position). Also the stepfeeder gear is assembled with the flush side up, protruded side down. If you don't get this right, you will be splitting the case again. Also, take note of where the clutch nuts are in relation to the studs. I have found they are generally flush with the studs. So upon assembly, screw the nuts down so they are flush with the studs before you bend the tabs up. Hope this helps.

You can also download/print off the workshop manual this is in the tech ref part of this site..it is V large.. but details all the steps involved in splitting the engine.. and as indiacted above..the correct setup for the "timing" of the gearbox.. includes all sorts of helpful stuff..