In case you're here searching for water pump replacement on an MC28, hopfully this photo can help. I don't own an MC21 or older models, so I can't speak for them.

The oil seal should have the spring part facing toward the bearing.

Hopefully it's captured here in photo link. Obviously the crankcase separates the oil seal from the bearing.

The T2R kit looks great! Comes with everything except the impeller!

Hope this helps!
Dana

Seal Order: https://drive.google.com/file/d/1wdN7gDxUi8arsCWbHlgkVnMzrXcZSZMJ/view?usp=drive_link

T2R Replacement Kit:
https://drive.google.com/file/d/10hqBRiDcwAaPzllS_abyhC6StipQMdlX/view?usp=drive_link
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2016 Husqvarna 701SM
2021 Husqvarna FS450 supermoto
1995 NSR250r MC28