Jackshaft left side chain tensioner
I have a "Sick Bike Parts" shift kit on my bike, and really like it, but it does take some care in setting up. One thing for sure I would do if you order one, is include the left side chain tensioner.
The reason for this, is not so much for it's ability to take the slack out of the chain (although that's nice), but that the kit includes a third bearing for the jackshaft itself, along with the extra bracketry to install it.
This really stiffens up the whole drive set-up, and I'm betting will eliminate quite a few alignment, and durability problems down the road. Below is a picture of the left side of the engine, with the left side tensioner gear's third bearing set in place.
As well, the bracket makes a nice chain guard.
- - Just my thoughts.