I think Mark mentioned thick & thin fibers.
Are yours thin. If not can you try a thinner set.
I guess you 'don't have a steel at the back? as the hub is built to take the fiber against it.
Was only thinking a steel there that ya don't need would make a difference in the right direction.
Any change you make to the plates you'd need to consider the pressure plate might bottom on the hub before compressing the plates.

Coming up with maybe stupid ideas [what i'd do lol] & remove the adjuster then stack washers under the spring to hold the arm up higher than the adjuster will take it. Then The taper will be higher up & lifting sooner. Depends how much room for lifting it you have before it ends up above the pushrod.

I will dig into an engine and some parts today. 

   This engine must have got hungry and started eating the piston . ha ha 

Pah, call that hungry!!! 

Advert for this Suzi GT550J read "engine seized due to standing"! No mate, it seized and was then left standing for 30 years! 

 

 

First thing I'm going to say is that I've been a little reluctant to get involved because I asked what *I* think are simple questions that could help solve the issue but did not receive responses...  maybe my requests were missed or maybe not understood?  Some were on the history of the bike which I think were eventually answered...  One hasn't been (unless I missed it) and I'm sure I asked at least twice before now...  How thick are the friction discs?  
Anyway, I have an engine that was ridden hard and put away wet...  it was in a 74 DT175 that was stripped and modified to be an MX race and play bike that a local young lady rode the wheels off of on a local track.  Almost nothing on the bike was original when I got it and it was maintained by capable young mechanics who basically flew by the seat of their pants...  In other words, it's not a good example of "original".  But the clutch did work fine
I took lots of pictures as I took it apart but might have missed something... here goes from top down: Underside of pressure plate.  That's a "132" on the casting for reference.  (Yamaha made several versions of 125/175 clutch parts that can be interchangeable but are NOT always the same... for example you could install a pressure plate that has an adjustment screw in the center from a different year. I can't read the numbers on yours and it might not make a difference...  but it could have been swapped with a taller one or something.)
 
Here is a picture of the clutch with the pressure plate and pushrod removed.  (Note that this engine DOES NOT have a stock clutch pack installed!  It is using 4mm frictions instead of 3mm so someone removed the final steel plate to compensate from what I can tell.  Stack starts with a friction and ends with a friction. Seemed to work?)    Note how the nut is pretty flush with end of shaft.  This is not uncommon.  Sometimes you'll see a thread or two.  More on this in a second.  (I'm just documenting things I've noticed over the years...  not saying yours is a problem.) 

Here's a picture with nut and washer removed.  Note how splines extend through inner hub slightly.  That's why the nut has a "relief" on the bottom side. Main point of picture is that if splines are more than a few thousandths lower or higher on this model with respect to inner hub, likely there is an washer/spacer issue.  This can affect adjustment.
 
More to follow.... 

Hi All, so the pressure plate has the number 13200 stamped on it and the clutch plates i bought as a kit from yambits in the uk and the friction plates are 4mm the steel ones are 1.5 mm there are 5 of each . i didnt know they did different thickness ones ! 

Side view showing gear alignment and height of first friction in outer hub.
 

Thrust bearing stack under inner hub
 

Outer basket. (17400)
 

On this engine there are two washers under the tall spacer and kick gear.  I'll have to go back and measure them. Edit: Total for both is 3.6mm
 


 

Finally the pushrod  and lever arm!

The "mushroom head" pushrod measures about 58.3mm from end to under head.  (I think you measured overall length)
 

I flipped the engine over, shook it, tapped on it, and no ball fell out. 

With mushroom pushrod installed and internal adjustment at maximum freeplay position (eccentric adjusted so lever is down in case as far as it will go) there is a small gap between underside of pushrod and end of shaft.  (Gap looks bigger in picture than it is... It's just a tiny bit above end of shaft.)
 

Pushing on end of pushrod with my finger, lever on case pretty much aims straight across.  If I try to rotate the lever on top of the case either direction, I feel the pushrod lift out of the end of the shaft.
 

Finally I measured how far down inside the shaft the end of the pushrod is located.  I came up with right about 58mm.  Which coincides with tiny gap and mushroom pushrod length approximate measurement. 
 

Hopefully this helps you figure out your issue.



 

Jez wrote: "Hi All, so the pressure plate has the number 13200 stamped on it and the clutch plates i bought as a kit from yambits in the uk and the friction plates are 4mm the steel ones are 1.5 mm there are 5 of each . i didnt know they did different thickness ones !"

My apologies.  I had a rough night, barely slept...  I believe I could have misspoken..  The engine I took apart had 4mm plates and yes it had a "steel" missing from the diagrams. (Edit, see subsequent post, worn clutch had an extra friction!) Somewhere in the 74-76 era Yamaha went to 3mm plates. I think it was in 1976, I'm not sure.  That's what the parts books say.  My 1976 definitely has 3mm frictions.  And I'm not sure I trust the parts books that say that was the first year.  I was contemplating that "maybe" this model should have had 3mm plates?  I didn't word that very clearly.  I really don't know.  All I do know is this bike had 4mm plates and one steel missing. 

It also could be the parts diagram shows an extra steel by mistake?  I highly doubt this and a non-splined pressure plate should end with a steel which is impossible to do if you remove one. 

"By the book" your model should have 4mm plates.

Hope the other info on pushrod helps.