93 intruder 1400, what are the specs on clutch disk, when to replace ?

Check the sidestand switch and the clutch switch. Both of these will give the same problem.

No it won't leak into the motor, nowhere does the clutch fluid get close to the insides of the engine.

Refill the clutch reservoir to look for leaks,

Change the fluid in the clutch reservoir,bleed out the remaining fluid.(keep it full as you go) Should be dot 4 fluid not dot 3. U may need to rebuild the master cylinder or replace it.

That is more than enough movement. Most probably don't move half that much. All they have to do is release the spring pressure from between the plates.

try replacing the fluid on this and bleed system good,clutch adjust may be needed

Maybe, and maybe not. If it is a problem with the master cylinder, then it could be bleeding back into the reservoir.

If it will not pump up and pressurize, and there are no signs of a leak, then you need to look at the master cylinder.

Yes, the bad news is bent shift forks. The engine comes out and dissassembles into about 75 different parts. The gears come out, the the shift drum, then the forks. Not a job for the Saturday mechanic.

No adjusting is possible.
Slip can be caused by several defaults:
- Wrong engine oil ( SAE 10w-40 API SE or SF only )
- Weak clutch springs ( free spring length : 34mm ( 1.34in ) MINIMUM
- Worn clutch disk 2(internal teeths ) ( wear limit 3.15mm ( 0.124in ) ) This is the last disk, against the clutch center
- Worn clutch disks 1 (internal teeths) ( wear limit 2.62mm ( 0.103in ) )
- Clutch plates ( thikcness between 1.55 and 1.65mm / 0.0610 and 0.0649 inches
- Damaged pressure plate ( cracks round the spring holes )

To check the clutch parts, the right engine cover must be removed.
Take attention while loosening the clutch spring bolts!
Drain engine oil, and set engine into first gear ( this locks the clutch for an easy loosening of the spring bolts )

Hope it helps