Topic: Clutch Adjustment Sadness...cannot get it to disengage

[ron.cieri.313]

one more question...the locknut which goes on to the shaft to hold this mess in place...does the tapered side face outward?...the thingy on the far right..thx.

[CB750F2]

G'Day Ron. The fact that you could not make the clutch release even though you adjusted the clutch adjusting screw screwed all of the way in with the lock nut removed and little or no free play at the cluch lever then it does
point to incorrect assembly of the clutch. Other posts are pointing you in the right direction but I will add a couple of comments to re-inforce what has been written.
Clutch Pressure Plate to Clutch Hub. The grooves in the hub need to mesh with the teeth/grooves in the pressure plate. If they don't the four posts of the pressure plate will not protude as far as they should. The consequence of this is that when you assemble the four springs and clutch lifter plate and try to bolt it down until the four posts bottom out in the groove of the clutch lifter plate you will need to compress the springs a lot more to achieve this and may even crack the clutch lifter plate. Even if you do achieve this it would mean that the clutch lifter plate would be sitting in the wrong position making it almost impossible for the lifting mechanism to make contact with the clutch lifter plate. Is this your trouble? If it is you will need to remove the pressure plate from the hub and rotate it 90 degrees - not 180degrees.
Clutch Lifter Plate. As stated by others the four posts of the pressure plate must bottom out in the groove on the inside of the clutch lifter plate. I get the impression that you have been using torgue to adjust the tension on the four springs. Once the four posts bottom out the tension of the springs is set and the bolts are torqued to stop them from coming loose. Also take note of the comment by Bodi about the correct position of spline washer. Pat
Washer.                                                                                                                     

[nteek754]

Hey all, I found that after putting new plates back in the basket I then will hold on to one of the bolt post, keeping the plates messed togeher. I got lucky one time snugging the four bolts a bit at a time and all of a sudden a quick snap NOPE no breakage just the plates were a bit out and just happened to slip in where they belonged. Like I said I got lucky. Now on my 1970 836 with a racing clutch I have a hard time getting the clutch to fully release. Im wondering if the accuator balls are maybe worn down a bit to hinder the proper throw. My adjustment screw is in moe than specs call for,and the clutch does not slip when driving the bike. But like if I am say rollng at three miles per hour and pull clutch in and rev it it wants to kinda go forward I mean I can hold it back with my legs, but just cant get rid of that wanting to go forward. I hav a bunch of other accuators but dont have a new gasket on hand so don want to pull it apart without picking some brains here. hope someone can help  Craig in Maine.

[ron.cieri.313]

Thanks Pat...I think this probably is the problem...

...however, I have a question on the 90 vs 180 degree...I'm assuming the following from eveyone's insight...

...there are two ways to put the pressure plate onto clutch hub in which the teeth can mesh with the grooves, however, only one of those ways will the teeth mesh with grooves and properly seat the best...this eliminates binding at these contact points and allows the bolt stems to extend the properly length through the holes and not overly compress the spring beyond intend length and therefore does not put excessive pressure on the lifting plate which could break it.

so, I already had oriented the pressure to the clutch hub so the teeth meshed with the grooves but, most likely, not the optimal one of the two possible...consequently, peeps have been suggestion rotating 180...do I have it right?

[MCRider]

Since I can't answer your question, I'll say something else. At this point don't get hung up on 90 or 180 degrees. You only have 4 choices. Pick the one where everything seats the best.

[ron.cieri.313]

Well said MC, well said.

[Tower]

One worrisome point you mentioned, Ron: The disk and plate stack that was installed before did not have the double rivetted plate.  So, you are replacing a single-width steel with a double-width steel.

This is worrsiome because there are three CB750 clutch designs, each with a slightly different disk and plate configuration.  The latest version has longer basket, hub, lifter piece and clutch cover, allowing room for the double-width plate. This longer version was introduced shortly into the 1976 model year (around March).  The configuration shown in your picture is correct for the longer clutch model.  

Previous clutch designs were shorter.  If you have the shorter version which came on K bikes up to serial: CB750 E #2700014 (or F models earlier than CB750F E #2557523) then you must remove the friction disk closest to the pressure plate otherwise the plate stack will be too thick and you will get the symptoms you described.

Note: On the shorter clutch models, keeping the double plate and removing a friction disk is a better option than using the original 6 single thickness plates and 7 friction disks.  The double plate goes a long way in reducing clutch noise.

Edit: I am referring to your plate stack configuration.

[mystic_1]

The Service Bulletin for eliminating clutch chatter in the 750 recommends installing the riveted double plate in place of a single steel plate, and then removing one of the friction plates to bring the stack height back to nominal.  Is this what you're trying to do?


BTW here's some pics of the spline issue, hth:

http://forums.sohc4.net/index.php?topic=36525.msg377135#msg377135

mystic_1

[MCRider]

The Service Bulletin for eliminating clutch chatter in the 750 recommends installing the riveted double plate in place of a single steel plate, and then removing one of the friction plates to bring the stack height back to nominal.  Is this what you're trying to do?


BTW here's some pics of the spline issue, hth:

http://forums.sohc4.net/index.php?topic=36525.msg377135#msg377135

mystic_1

Man the pictures in your link are gold!

[ron.cieri.313]

The Service Bulletin for eliminating clutch chatter in the 750 recommends installing the riveted double plate in place of a single steel plate, and then removing one of the friction plates to bring the stack height back to nominal.  Is this what you're trying to do?


BTW here's some pics of the spline issue, hth:

http://forums.sohc4.net/index.php?topic=36525.msg377135#msg377135

mystic_1

Whoa?!..."and then removing one of the friction plates"...yes, i only removed single steel plate and replaced with the double plate AND did not also remove a friction disc.

[mystic_1]

Sorry, this is not a Technical Service Bulletin as I said but rather an article from The Wrench.

Here ya go:



mystic_1

[ron.cieri.313]

Behold, the missing link...

so, if I'm reading this correctly, I need to remove in addition to the metal disc (done), the friction disc closest the the pressure plate?

I'm optimistic about this!

[Tower]

Ron, from your posts, you have identified several "potential" issues:
1) Short clutch using long clutch plate stack
2) Pressure plate rotated 180o (Pressure plate not seated against lifter plate)
3) Custom length clutch cable
4) Hybrid clutch parts

I have given you various suggestions as you worked your way through the problem.  In order to find out which is the correct/definative answer you must do some trial-and-error work.
Do your tests in this sequence:

1) Rotate the pressure plate 180o and keep all the disks.  Which orientation seems to be a better fit? (Can you seat the lifter plate - without springs, when stack is assembled?)
 a) If cable adjusts properly and not bindnig - DONE
 b) If your result is cable will not adjust properly and clutch still binding - do step 2
 c) If result is cable will not adjust properly, but clutch is not binding - go to step 4

2) Original pressure plate position and discard the friction disk.
 a) If cable adjusts properly and no slipping at speed - DONE
 b) If cable will not adjust properly and clutch is still sticking - do step 3
 c) If cable will not adjust properly, not sticking, but clutch slips at speed - do step 4
 
3) Rotate pressure plate 180o and discard friction disk.
 a) If cable adjusts properly and no binding no sticking - DONE
 b) If cable will not adjust properly - do step 4

4)Replace the cable you are using with a stock cable
 a) If still unable to adjust clutch then you have hybrid clutch parts and may need to replace one or more of clutch centre, lifter piece, springs, or clutch cover

[ron.cieri.313]

Okay, not exactly what I was hoping for but definitely a ray of sunshine coming through the clouds...

I finished late last night, so only could do a small test run this am...no more destructive, nasty clatter sounds when shifting into first or second BUT...still getting hung up in neutral...ie., I have double shift from second into first or vice versa.

Here's what i did last (apologizes to Tower because I wasn't as methodical as I could've been...but your tip on pull on the lifter plate to get the teeth meshed was invaluable)...so, I took out the friction disc indicated in "the wrench" article (the single metal plate had already been removed) and I also rotated the pressure plate 180o from where i had it...honestly, i can't see much of difference but i'm sure you guys are right, you always are.

Like I said, I didn't get to do much of a test drive and any further adjustments...is it possible I just need to tighted the adjusting screw and/or cable a bit?  The clutch lever feel okay but definitely room to tighten me thinks.

...any other suggestions?

...and I'm hoping that this rules out the need to split the cases and go into the transmission case as all the bad noises are gone...think this is right?

...thx, ron.

[mystic_1]

I finished late last night, so only could do a small test run this am...no more destructive, nasty clatter sounds when shifting into first or second BUT...still getting hung up in neutral...ie., I have double shift from second into first or vice versa.

OK, that's good, sounds were probably clatter from the gear dogs, a result of the clutch not fully disengaging.

The "getting hung up in neutral" thing sounds like a selector mechanism problem, have you had a close look at that side recently?

At this point I'd do all the fine adjustments on the clutch and call it done, then move on to the shifting problem.

Keep us posted.

mystic_1

[ron.cieri.313]

Yeah, think I need to adjust the clutch as best I can before jumping to too many other things but, I can shift between first and second without double kicking when the bike is stopped...also, I had the shift mechanism off when troubleshooting the original oil flow problem in the countershaft bearing cover....don't cha' think that indicates a clutch issue more than a shifting mechanism problem?

[mystic_1]

Possibly.  That's why I recommend adjusting the clutch fully before moving on, the problem may go away once you get the free play right.  You might still have a small amount of drag even though you're obviously much closer now.

mystic_1

[ron.cieri.313]

Cool...still may need some babysitting, so pls stay tuned.

[Tower]

Sounds like you have your bike up and running.  That's good!

The extra room in the basket created by removing the friction disk means a longer lever throw and it should translate into making it easier to find neutral.  Also, since the clutch spring pressure is reduced, you might want to test your clutch for slippage (once you have the cable adjusted properly).  If there is slippage it could mean you have a long clutch basket and did not need to discard the one friction disk.

Since you went straight to step #3 you don't know for sure if the pressure plate is correctly oriented, nor if it was necessary to remove the extra friction disk.  But, hey, if it works to your satisfaction, why make trouble?

I wanted to save this for the last...because its rare in street use and unpleasant to deal with....but there is one more concern that your situation exposes.  One symptom is a clutch lever that feels rough when squeezing and does not pull smoothly towards the handlebar and a clutch that often drags or bounces before releasing.
 
Here's the explanation: Since you had an oil shortage problem inside the clutch, you must be sure that the inner and outer baskets are not worn excessively.  I can't really tell from your pictures whether or not the inner hub is worn.  I see the glossiness created by the plates, but if you ran your finger down the groove: Are the glossy areas indented?  If they are well worn, then the plates have worn a pit for themselves and will resist moving smoothly along the hub when the lifter is actuated.  The friction disks can make similar grooves in the clutch outer drum with the same effect.  Lack of oil precipitates this condition as does "snap" releasing of the clutch lever.  Unfortunately, the only remedy in that case is new parts. 

Like I said, its rare and usually found when the clutch outer has been stretched causing excessive play which further quickens the creation of these grooves.  Never-the-less, it might be worth checking.

[ron.cieri.313]

Well, here's the dealio...adjusted the clutch so it is firm and very little free play at the lever.  It is smooth when released but a problem persists...the darn double shifting, and if my rpm's are high, some minor clattering when moving from neutral to 2nd...which is the only way I can get into second as she does not shift directly from 1st to 2nd.

Btw...2nd to 3rd, and so and back are fine.

Its nice to ride the girl but this problem is frustrating.  There must be something wrong still...cable length?...but I don't even have the bottom length adjuster out all the way...I'll post pics soon.

[mystic_1]

You could have a worn shift fork.  Unfortunately the only way to be sure is to split the case.  That would explain why only going from first to second is a problem.  Any issue going from second to first?  The shift forks frequently only wear on one side for some reason.

mystic_1

[Tower]

Ron, I'm afraid you are no longer in the clutch zone....but entering the shifter and transmission zone 

[MCRider]

Like any good Dr. we need a history. Maybe you've given it but let's refresh.

Is there anything in this bike's past that would indicate a problem other than the clutch? Was it abused, speed shifted, drag raced, did it have a hard fall on the shifter side, anything?

Like a Vet's job is the hardest, machine's and pets can't talk. At least a pet can whimper or give some expression when you press on the hurt.

[ron.cieri.313]

I was afraid of this...i.,e entering a new scarier zone...well, the trouble is both ways 1st-to-2nd and 2nd-to-1st.

The bike has about 23,000 miles on it and the transmission shifted fine when I first got it running.  It developed this problem soon after doing WOT plug chops to help with carb rejetting.  The bike's back end is lowered and has 10inch ape hangers so its been made into a cruiser of sorts so I don't think it was raced.  The po never rode it as he never got his license and had it sitting in his garage for about 4-5 years.  The po before the po was a plant mgr of sorts...when my buddy, retired from Chrysler he bought it from the plant mgr as a retirement present to himself.  He doesn't work on bikes so he paid people to bring it up to snuff but never did it completely...they never rejetted so the bike always sputtered on him...i don't know if his mechanic or the former po took off the stock air box.

I thought the problem arose after the plug chops because the oil got worn thin or that maybe there was a circulation problem and the clutch wasn't getting lubed...I dropped the oil pan to clean the screan on the oil pump and worked my way up and found no oil come through the shaft to the clutch...the problem was fixed and then I rebuilt the clutch, which you are all familiar with.

I've put alot of work into this girl but she just won't be convinced.

[MCRider]

Man, you've got a weird one. I may not have more to offer. They are really pretty hardy. THe most common tranny problem is jumping out of second. THat is usually always due to abuse. THe bike is on the line already in first, the light turns green, drop the clutch and just seconds later bang it into second. Bends shift forks and wears the engagement dogs. But it usually will go into gear no problem, it just won't stay in gear. And 2 to 1 is no problem.

Good luck