Should I be tightening the cable when the throttle is pushed all the way forward(closed)? or open or half and half? I dont understand
Not really sure what you are describing. Half and Half really isn't an option.
Install the cables in the twist grip first. relax the adjusters completely. The A cable (the one with the adjusters) goes in the front hole, the B in the back. Heree's where I'm a little foggy: install the B cable first, on the lower part of the pulley/bell crank. Then pop the A cable in.
The adjusters on the A cable should be fully relaxed. There is one at the grip, one at the bellcrank (the partial pulley affair that the cables hook into.) on the carbs.
You would tighten the adjuster at the bellcrank till the cable allows a small amount of turning of the twistgrip, les than 1/8th turn. Then tighten the adjuster at the twist grip until most, but not all of the slop at the twist grip is gone.
I've been raised to leave the tiniest bit of slack at the twistgrip. I agree. You should turn the twist grip 1/16 of a turn to pull out the slack and then start to open the carbs. This bit of slack allows the full return to idle.
The B cable has no adjusters on it.
I'm sure I've missed some nuances, like the routing.