Clutch problem , slipping

[SJK]

The distance on my transmission is 11cm. 

I measure 22cm :mbird

think I'm misunderstanding the place of measure ... from the front of the gearbox(spline)  thru to the back rim where the boot clamp goes ?

[The Mighty Gryphon]

Ouch!!!  I measured in inches.  Let me check again. 

Meanwhile, here is a photo of the parts at the back end.  When stacked they are 22.5mm.

[The Mighty Gryphon]

22cm

[SJK]

Thanks. I can cross that off my bucket list. Next on the list is snorkeling with pirahnas in the Orinoco.

The top photo is the adjusting bolt's position when the clutch was slipping and you removed the arm assembly?

correct sir, even with the bolt totally out , if I was to attach the arm to the cable(set at its max , way more then 75cm & the rubber boot on the verge of ripping due to the spring) the clutch would be in a half engaged/disengaged position . bike will rev high but no power

[Filmcamera]

So Gryph has the older style multi piece puck not the new style one piece that SJK seems to have, it also seems that the clutch rod that Gryph has measures the same as SJK's.  I still think that might be the issue.

[SJK]

Meanwhile, here is a photo of the parts at the back end.  When stacked they are 22.5mm.

ok thanx , my piston/puck also measures about 22mm (using a tape) I do have a different design though , apparently a new replacement part

[The Mighty Gryphon]

Is it possible that the old inner race is still in there?  Outside of the front end not going into the engine output shaft pilot bushing that is the only other possibility for your problem that I can see.

[SJK]

So Gryph has the older style multi piece puck not the new style one piece that SJK seems to have, it also seems that the clutch rod that Gryph has measures the same as SJK's.  I still think that might be the issue.

correct , this has been bugging me hence the drawing I made earlier today to try confirm the sizes of my Pushrod with the newer piston/puck(23 13 1 464 167)

BMW in South Africa cant get or find me any info or sizes on my K75 Pushrod as the bike it too old apparently  ,
I have emailed Max BMW the drawing I made asking some of this info, waiting for reply

[The Mighty Gryphon]

How easy is it to slip the end of the pushrod into the puck?  On my parts it is a very tight fit and assembly requires tapping the inner race of the puck onto it.  I could see how that would make things stick out 7mm too far.

[SJK]

Is it possible that the old inner race is still in there?  Outside of the front end not going into the engine output shaft pilot bushing that is the only other possibility for your problem that I can see.

I doubt , because with the gearbox on the workbench the piston/puck slides right in , its definitely the pushrod that is stopping the Puck from going into position

[Laitch]

I have emailed Max BMW the drawing I made asking some of this info, waiting for reply

:2thumbup:

[SJK]

How easy is it to slip the end of the pushrod into the puck?  On my parts it is a very tight fit and assembly requires tapping the inner race of the puck onto it.  I could see how that would make things stick out 7mm too far.

mine goes in very loosely , I really think this is a older Pushrod working with a newer Piston/Puck problem...but cant confirm with BMW or anyone  :dunno2:

[The Mighty Gryphon]

The way I read the parts fiche, there is no older/newer pushrod.  Only one P/N is shown.  there is mention of a bushing #14 on the drawing that needs to be removed for the new puck. I can't see it in my transmission, so I can't say what you should be looking for.

[SJK]

yes my #14 is no longer on the Pushrod

[Laitch]

In the attached photo, a dark ring is visible in the metal indicated by the arrow raises a question.
Is the shoulder milled into the rod stopping the rod at that point on the piston from traveling further into the piston?

[Laitch]

I've called the parts depts of both MAX and Bob's. Neither had a push rod in stock to measure nor data that supplied a measurement.

[SJK]

In the attached photo, a dark ring is visible in the metal indicated by the arrow raises a question.
Is the shoulder milled into the rod stopping the rod at that point on the piston from traveling further into the piston?

yes that is correct , that's why I was asking for that #C measurement on my drawing (7mm). the hole in the puck is definitely a few millimeters deeper then 7mm

[SJK]

I've called the parts depts of both MAX and Bob's. Neither had a push rod in stock to measure nor data that supplied a measurement.

Thanks Laitch

[The Mighty Gryphon]

The distance from that shoulder to the front of the puck should be 22.5mm to match the original parts stack up.

Is it?   If so, that shouldn't be your problem.

[SJK]

The distance from that shoulder to the front of the puck should be 22.5mm to match the original parts stack up.

Is it?   If so, that shouldn't be your problem.

The size of the Puck is 22.5mm like you say but Myself and  Laitch are talking about the actual hole in the puck , and the depth that the Pushrod goes into the hole

[The Mighty Gryphon]

The shoulder of the pushrod rests against the face of the puck. 

Overall length should be 253mm - 7mm + 22.5mm = 268.5mm 

[Laitch]

If this were my bike, based on all I've read I would decide that clutch misalignment is the problem. I think that when the engine is mounted, the clutch push rod is hitting the edge of the diaphragm spring hole rather than entering its center. It's difficult to detect that misalignment when inserting the rod with your method.  An alignment tool is needed for the best result. I've come to this conclusion because I found no specific data supporting a change in rod length for the K75—only that ambiguous reference in the parts fiche. Maybe one of the experience pro BMW mechanics that are members here will sound off about this symptom.

You can always take a few more stabs at realignment then remounting the transmission to check. It's a good upper body workout. You seem to be persistent so I think this will get sorted sooner than later.

[The Mighty Gryphon]

All of the dimensions you have checked look correct compared to my transmission that had no installation problem.  I am inclined to believe that all of the clutch rod and thrust bearing components are not the problem.

I would suggest that you go back to the clutch pack assembly.  Be very careful reassembling it, especially with regard to alignment of the diaphragm spring.  Also, make very sure there is nothing interfering with the insertion of the end of the pushrod into the end of the engine output shaft.

[Filmcamera]

I think you are all correct and that the push rod is not being allowed to travel far enough into the clutch pack when it is installed on the bike.  Take it all apart and take photos of how you put it back together.  One way or another we can crack this!

[Elipten]

Time to buy the clutch alignment tool or use the input shaft off a spare transmission.


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