I have recently had the engine out of my st125 .On refitting the clutch push rod dropped out. When refitting  the slave cylinder it appears the either the push rod is not seated or slave cyl piston is out too far (tried pressing it back in). So when built the clutch is always disengaged. Sherco web page down so can’t see diagrams, any ideas. 
cheers.  

Well, if you haven't operated the clutch with the engine out, the slave cylinder piston shouldn't be any further out than it was when you removed everything. So I would say that the pushrod isn't sitting correctly at the clutch cover somehow, or something is assembled incorrectly. Either way should be quite easy to see the problem if you just whip the side casing off and take a look.