Hi there. New to the forum, so I'd totally appreciate any help. I put together a 2001 LS650 from 1/3 of a bike plus boxes of parts. The good news is I have it running. However, I've not yet tried to ride it because I can see the clutch is out of adjustment. There is no slack on the handlebar lever. Clymer says to turn the adjuster at the engine, but whenever I do this, the adjuster just turns back to its original position. The sleeve on the adjuster is integral to the cable cover, so I don't see how to turn the adjuster without turning the whole cable, which would necessitate taking tank off, which is not my first choice of options!   Thank you in advance for any help.

The bottom end of the cable should have 2 nuts on top of the aluminum mount in the case.  You need to take 2 wrenches and loosen the nuts, then turn the nuts to make more slack in the cable.....if the cable wants to rotate then hold it with something so that it does not turn when adjusting the loosened nuts.  Then tighten the nuts back up.

NOTE:  The nuts both need to be above the mount....some folks have foolishly put one nut on each side of the mount and broken the mount off the engine case, and that is very bad and very hard and expensive to fix.

Thank you everyone for your help! I'll give this a go and let you know how I get on!