6-speed Transmission Swap Instructions

Fishrider, you are absolutely correct and I made an incorrect assumption that one of the bearing races behind the clutch basket was missing. It dawned on me that in your previous picture that the nut was flush with the end of the shaft. Meaning everything was in its place. You investigated before I could make a correction to my post.  I misled you and for that I apologize!  

But….in referring back to the picture of the clutch basket, and the one with the release rod and your bushing, it dawned on me that the roller bearing shim is in the wrong place. This may just be the way you mocked it up for pictures, but if not, it’s a huge problem. 
The roller bearing goes on the hardened release rod first and then the hardened bearing race (or shim as it is called in the parts list) so that the roller bearing is sandwiched between two hardened surfaces. If the bearing goes on last, then it will be rolling and pressed into the soft aluminum pressure plate when the clutch is applied.  That means the roller bearing would have eventually seized and then the release rod probably would have started rotating with the pressure plate. If the release rod is now spinning it may have sawed the tip off where it meets the release lever. 

Or……I believe that it simply may have been the clutch lever wasn’t properly indexed and the clutch cable was adjusted to the point that the clutch release lever was always in contact with the pressure plate and was constantly spinning even when the clutch lever was released. Eventually the roller bearing would have seized and the the release lever would start spinning with the pressure plate and it sawed the tip off at the release pawl. 

 Correct bearing and shim order

Pictures showing shim in wrong place  
 

+1, Daftrusty´s explainaton is excellent. If the bearing washer is missing on the spring pressure plate side the clutch pull rod will rotate instead of the roller bearing. Was the bearing installed anytime or did you run the engine with the bearing washer only?
 

I realized that in the pics myself that the bearing was missing, but it was never installed that way as far as I know.  Or, at least, I never installed the release with the bearing second.  Not sure if the mechanics did.  IDK, I didn't check when I took it apart the first time.  I should have, but I was not in the right state of mind.  I think when I took out the rod the last time for pics the bearing and washer fell off, and I lazily just grabbed the washer.  

A possible issue may be that the shaft is putting constant pressure on the release rod because my cable is a skosh short.  How should the clutch feel when it is released?   When I set the lever at the correct index, I did have to turn the shaft a bit to get the lever on.  Should I not have to do that?  Should I be able to place the lever on easily, and then take up the slack with the adjuster at the cover and on the handle?  If that is the case I may have to make a new cable. Which would be interesting really, because I would think the mechanics would have recognized that issue instead of pawning off the problem on a bushing.  Which I still think was a good idea.     But hey, all this problem was caused by a pin that I installed backwards during the original rebuild.  This bike would have been done a year ago if I hadn't putzed that up.  

So I started it up today after putting everything back together the way I though it was supposed to go with no bushing.  After letting the engine warm up, I pulled the clutch.  I heard a distinct scraping sound.  I pulled the clutch just a few times to make sure.  Every time the same sound.  So I drained the oil and pulled the cover again.  The shaft is definitely somehow pulling on the rod incorrectly.  You can see the damage being caused to the shaft.  I made a short video with what I think is happening.  My motion is exaggerated but it shows what I think is happening as the gouge on the shaft perfectly matches the outer ring on the clutch rod.  Eventually the rod gets worn down then slips off the clutch rod eventually putting enough pressure on the clutch rod from an odd angle that the rod gets bent and then breaks.  I am at a loss how to fix this.  I posted this in the Zephyr Zone as well.  

Edit: Is it possible the rod is being pulled out of the shaft too far and has a slight angle to it when the shaft puts pressure on the rod?  Could making the end of the clutch rod that sits inside the shaft longer solve the issue?  Or it this something to do with where the clutch shaft is sitting?

I wasn't sure the video tags work, so I posted the url below.

www.youtube.com/shorts/R1YOkzExcFw

I think I am getting some deflection as I surmised in my edit as you can see in the video. With the rod being pushed out a bit further when the shaft is actuated I think the deflection is even further. I had, originally, thought that I may need to somehow lengthen the part of the clutch rod that sits in the shaft either by having a new piece made or mating another piece to the clutch rod by a threaded piece. Although, currently this is all theory.

www.youtube.com/shorts/R1YOkzExcFw

Looks like the clutch accutator rod position is off center and has to be 5 mm more far out of the clutch cover.

 

When I install the shaft, it seems to engage just how it should.  Also, I thought the stop on the clutch cover that the shaft sits on keeps the shaft in the correct vertical position.  The output shaft is not in a different vertical position.  Everything lines up the same as with the old output shaft.  

I cut a whole in my broken clutch cover to be able to see if there was a problem actuating the clutch rod.  After being able to see inside the clutch I think Scirocco diagnosed the problem correctly.  I believe that not only did I install the shaft incorrectly, but I think the mechanics did also.

The first video shows actuation of the the clutch plate when the shaft is installed properly.  
www.youtube.com/shorts/zDMkkxXCWVM

Second video shows how much movement I am getting with the clutch rod having less surface area inside the transmission shaft.  I am not sure if this caused any of the original problem.  Personally, I think the issue was caused directly by incorrect installation.  However, I am going to affect a fix and effectively lengthen the output shaft which should stop the movement you see in the video.  I'll update this once I get the fix operational.  


This third video shows what Scirocco explained.  With the shaft installed too far down the shaft does not engage correctly.  


With any luck, I should be able to put my fix in place this weekend and give this bike a road test.  

Victory, your quest is over  .
Don´t forget to share your successful troubleshooting @ www.zephyr-zone.com/zz/viewtopic.php?f=10&t=281&p=4818#p4786 for future users.

As per usual, I show up late to the party….although I am supposed to get notifications of new reply’s on this thread, they have never worked. 


I’m glad you found the cause and solution to the problem. 
I am very interested in your custom release pawl/rod/actuator.  You may be a machinist and already aware, but it will have to have some degree of heat treatment as it is also a thrust bearing surface. Or you could just add another of the steel shims and it would serve as the  rolling surface. Either way, I’m excited to see what you come up with. 
Lots of good info here! 

Since that issue seems resolved, I'll add a little update on the 550 shaft transmission swap.

RPM in sixth gear at 70 is 5400, at 77 is 6000 - that's with a 120/90-18 Pirelli, thoroughly worn down. 

After ~1200 miles since installation, I would recommend this swap only for those who want to go fast all the time and never hit the freeway. It definitely feels quick and as I think I mentioned it does pick up the front wheel a bit without trouble, but...it's a lot of shifting, you hit redline pretty fast, and I feel bad going 80+ with the engine running so high.

So, 6 speeds for shaft owners - possible but be aware that it's a trade-off. 

Ghostdive - To help clarify for me and others who may read your post….
You did the 6-speed swap on a shaft drive 750?
On a shaft drive, there is no ability to change your final drive ratio by calculating and changing your front and rear sprockets to achieve the desired over-drive ratio. Were you aware of the effects of the incorrect final drive ratio when you performed the transmission swap?  Or was it simply a project that you wanted do just for the doing? (I do lots of those)  
I just want folks who research this subject to be aware that because of the final drive limitations of a shaft-drive architecture bike, this transmission swap is not advised!