Harley Davidson transmission questions

[Grant Borman]

Kind of out there but i figured i'd ask.  I am in the beginning stages of putting my Tiernay turbine onto the back of my laydown enduro go kart(looking to run at boneville/black rock/mojave for fun not in competition).  The original plan was to use a single speed and a centrifugal clutch but the only somewhat feasible clutch i could find was a HD auto clutch.  This led me into the standard HD clutch and trans option which i prefer over a centrifugal clutch but i have a few questions.  I plan to feed 80-100hp through the trans at around 6krpm's but im guessing i won't be near the torque limit since i won't have any pulses of torque like a v-twin. 

Can you shift under partial load or are the dogs to steep?
Can they survive prolonged higher rpm's? 
Stock it seems like they come with a wet primary chain and clutch.  If i run a dry clutch and a belt do i have to modify any seals?
Are the aftermarket transmissions a viable option or is stock the way to go?
Is there anything thats certain death for these trannys?

Im green when it comes to harleys but i know enough about transmissions to make a fool of myself lol.

Thanks,
Grant

[Jessechop]

Had I seen this earlier I would of responded earlier.

I assume you are talking a typical Harley 4 speed, or?

Yes you can shift under load. Yes they will take higher rpms. No big deal to run them dry, the trans is seperate from the primary as far as oiling, unless you are talking sportster trans and thats a different animal all together.

Baker is the cats ass. Stock is good. Ultima, Rev Tech, etc. have mixed reviews. I ran a rev tech 4 speed for about 35k miles on the street with no issues.

[saltwheels262]

if you are going after market; a jims transmission would be the best bet.