As far as clutch adjustment goes, it's pretty simple. If you have too little or no free play, you could have a partially disengaged clutch while you are riding and your clutch will slip and warp the plates. If you have too much free play, the clutch will not completely disengage while you are shifting and you will damage the engagement dogs on your engagement collars and gears.
There are a couple of points that need to be made regarding the clutch arm on the back of your gearbox. When adjusting your clutch, this is the first adjustment you should make. There is a spec in the Guzzi manuals for the distance from the boss on the side of the gearbox where the lower cable adjuster is held to the fingers on the end of the clutch arm. What you are doing here is setting the operating range of the lever. When the clutch is fully engaged (handlebar lever NOT pulled in) you don't want the clutch arm on the gearbox cover to foul on the frame crossmember behind it. When the clutch is fully disengaged (handlebar clutch lever is pulled fully to the bar), you don't want the clutch arm on the gearbox cover to foul on the cover. Set this via the hardened adjuster which goes through your clutch arm and then tighten the lock nut. Then set the adjuster at the clutch lever on your handlebars near the middle of it's adjustment range. Next, tighten the adjuster at the lower end of the cable along the side of your gearbox until there is no more freeplay at the clutch lever on your handlebar. Finally, adjust the free play at the lever.
If you have replaced your friction plates and intermediate plate, be sure to break in your clutch plates, just the same as you would for new brake pads. New plates need to "bed in" to each other or wear down small irregularities and high spots until they are making 100 percent contact. Until this bed in process is complete, the plates are prone to slipping and you can generate too much heat and warp your intermediate plate. Do a few hundred miles of riding where you will do lots of shifts and use only moderate acceleration. The more powerful your motor is (950cc and up especially), the more critical this is.
The other problem to watch for with the clutch arm is wear in the pivot where the clevis pin goes through it. Quite a bit of the motion of your clutch lever on the handle bars is wasted if this is worn. Due to the leverage provided by the clutch lever and the clutch arm(which is what allows you to compress 8 or 10 clutch springs) you only get about 100 thou(1/10th) of an inch of travel along the pushrod. You don't want to give any of this away with sloppy pivots. Be sure to include the clutch arm with your gearbox when you send it to me so I can ream the two arms on the back of the gearbox cover and your clutch arm and give you an oversize clevis pin.
Many of the stock shift linkages on Guzzis are junk. Guzzi gearboxes by design require a pretty long throw for a positive shift. If you give away much of the motion of your shift to taking up slop in the linkage you will miss shifts and damage your gearbox. These should all be converted to metric rod ends also known as heim joints with threaded rods and lock nuts. Worn shafts and bushings can be replaced. Look up the current price of sliding muffs and gears for additional inspiration.
More to Come Soon.................