Author Topic: Clutch Adjustment Sadness...cannot get it to disengage (Read 17139 times)

ron.cieri.313 · « **on:** August 07, 2009, 02:26:27 PM »

Hi all...I finished rebuilding my clutch with new friction discs, and also prior to that, fixed the probable main cause of my original hard shifting problem, the lack/no oil flow through the clutch shaft to the clutch basket.

But I can't check out if I really solved anything because I can only shift into first as I cannot (up till now and you guys tell me what I'm doing stupidly) get the clutch to disengage fully...she creeps when in first two and I cannot even get her back up into neutral

She is a 1976 Honda CB750K with "mini" ape hangers on it. I'm using a 10+" vs. standard clutch cable which is exactly an inch or so shorter than the cable that was on the bike when the clutch was working...I have pictures below.

Right now, the clutch lever is stiff but the friction zone feels way to close to the rear of the bike...i.e., the friction zone is close to the clutch lever being totally compressed as opposed to almost released.

PLease help...I've been trying adjusting the screw, the cable adjusters (handlebar and bottom adjuster)...I know I need to move the friction zone but haven't been able to figrue it out?!

...thx, ron.

ron.cieri.313 · « **Reply #1 on:** August 07, 2009, 02:27:33 PM »

ron.cieri.313 · « **Reply #2 on:** August 07, 2009, 02:39:00 PM »

Oh, one more thing...I think the good news is that I do not get a hard clunk when shifting into first like I did prior to the rebuild but it sure would be nice to use other gears...thx.

joeb · « **Reply #3 on:** August 08, 2009, 05:38:31 AM »

Do you have any free play in the clutch handle at all.

?

Tower · « **Reply #4 on:** August 08, 2009, 08:03:02 AM »

1) Assuming you used the right clutch parts for a 1976 CB750: These clutches are deeper than earlier versions and use longer springs.

2) Assuming you tightened correctly: Binding occurs when the clutch pressure plate is not seated properly on the clutch centre, or when the clutch pressure plate is assembled in a different orientation (rotated by 180o) to the clutch centre than was originally installed, or if one of the pieces is cracked.

3) Set clutch adjustment bolt correctly: Your pictures show both upper and lower cable adjusting bolts are in the extreme extended position - this is incorrect. It would then indicate the clutch adjusting screw (on the inner cover) is not turned in sufficiently. Note that sometimes it is difficult to detect exactly when the adjusting bolt makes contact with the clutch lifter piece. Best practice is to turn the nut out quite a bit before starting to turn in - this makes it more obvious the moment you feel resistance. In your case, I'm assuming its not in far enough, so, loosen the clutch lifter adjusting lock nut and turn the clutch adjusting screw 1/4 turn clockwise then relock and re-try the cable adjustments. You can repeat this until your subsequent cable adjustments fall into place. If they never do, then your problem is inside the clutch as per points 1) and 2).

4) Adjust cable and lever free play: Start the cable adjustment steps with the upper cable adjusting bolt turned all the way into the handlebar clutch lever and the lower cable adjusting bolts turned all the way into the clutch housing. Cable length is almost never an issue unless its way too short or the cable has been overly stretched. Use the lower cable adjusting mechanism first to set free play in the upper lever. Use the upper adjusting bolt only for the final fine tuning.

Page 183 of the service manual provides instructions, and there are plenty of posts on this forum that give you more hints.

ron.cieri.313 · « **Reply #5 on:** August 08, 2009, 09:52:35 AM »

I did have free play in the clutch lever, too much...I went back and re-adjusted per Tower's note and I think I may have at least identified the crux of the problem...

...in order to get resistance on the clutch adjusting screw, I have to turn it in so far that I can no longer have enough thread length exposed to even use the washer that is suppose to go onto the screw before the nut.

I removed the nut and arm entirely so I could feel the resistance and then turned it back out a quarter turn. Then using the lower clutch cable adjuster, removed the cable slack. Results, it still creeped and would not go into neutral until i turned the engine off.

So then I tighted the screw a quarter turn, same results...one more quarter turn, same results.

...so me thinks its something inside the clutch (again!)...can i forget about cable length?...seems like it. The clutch worked fine until I developed my hard shifting problem 6 months into owning the bike, so I assume the parts are correct and I used Honda brand friction discs to replace the old one. I did replace one of the metal discs with a new "double" center B metal plate. I tightened the bolts on the aluming clutch plate to spec using a torque wrench and everything seemed to fit in place wonderfully.

I did not measure the springs but the looked to be the same size but obviously something is wrong...please chime in before I tear this clutch apart again???...thanks, ron.

ron.cieri.313 · « **Reply #6 on:** August 08, 2009, 12:53:12 PM »

So per Tower's original note, I've decided to go back in like a reluctant surgeon.

Here's what I see:

The clutch basket looks neatly packed?..I wonder if the clutch plates screws are just on too tight and limiting play in the springs behind it...is that possible?

Bill/BentON Racing · « **Reply #7 on:** August 08, 2009, 12:59:21 PM »

Check those metal plates for warpage will cause it to be hard to disengage,and it will creep and be hard to find neutral.Bill

cben750f0 · « **Reply #8 on:** August 08, 2009, 01:34:16 PM »

just a question, when you had it apart, did you take the inner basket out?, the PO of my F1 rebuilt the clutch on my bike, and forgot to put the thrust washer between the inner and outer clutch baskets, then tightened it all down, this effectively made the clutch a direct lock up even when the clutch was pulled in, just a thought, its a small part easy to miss

good luck

peace

Bill/BentON Racing · « **Reply #9 on:** August 08, 2009, 01:40:04 PM »

Saw that recently ,it rubbed outer cover and would work but not well at all.Bill

ron.cieri.313 · « **Reply #10 on:** August 08, 2009, 01:59:05 PM »

Yes, I had the basket out and repacked with new friction discs and cleaned the metal plates which looked in good shape.

Do you mean the conical-shaped washer...yes, thats definitely back in and correctly oriented i believe.

ron.cieri.313 · « **Reply #11 on:** August 08, 2009, 02:43:25 PM »

I'm not sure what to do next?

...put everything back together and see if it works with the screws on the clutch plate loosened?...they are not "snug" but on as tightly as the torque wrench would have me do.

or

...take and measure the springs?...understand they should be 30.5mm

...suggestions?...thx...ron.

cben750f0 · « **Reply #12 on:** August 08, 2009, 07:39:21 PM »

the washer i ment was number 12 on this drawing?

peace

Tower · « **Reply #13 on:** August 08, 2009, 10:32:23 PM »

When tightened to proper spec the screws should be fully seated on the clutch plate. If they are not seating, then a) the plates and disks are too thick, too many or warped, b) you are using "hybrid" K6 parts, or c) the pressure plate has been rotated 180o from original, or it or the lifter plate is cracked, or d) the springs are way too long (this is unlikely since your clutch is the longest of all the CB750 clutches and was designed for the longest and strongest springs).

1) First, note whether or not the friction disk closest to the pressure plate is fully seated against the pressure plate, and at the other end, that disk is fully seated against the clutch inner basket. These disks come in two sizes and you may have the wrong (smaller) size. The friction disks should not have any space between them and the pressure plate or inner basket.
2) Scratch a mark on the pressure plate and hub to use as an orientation. Original orientation must be preserved. You may have inadvertantly rotated the plate 180o in reassembly.
3) Disassemble and check plates for warpage and disks for thickness.
4) Check spring length.

If the plates and disks are up to spec, then, the two other things you can try is 1) unbolt and rotate the pressure plate 180o and reassemble. If the springs and bolts still do not seat fully, then go back to the original orientation and instead remove the friction disk closest to the pressure plate and reassemble. Don't worry that the steel is next to the pressure plate as both of these components rotate together so no harm will be done to your clutch if its missing this disk.

Now try to adjust your clutch as you did before. This time there should be no difficulty with sticking - if anything the problem should be the opposite. If you can now adjust your clutch properly, you have narrowed the problem down to either clutch plate orientation or disk configuration.

Spanner 1 · « **Reply #14 on:** August 09, 2009, 08:21:48 AM »

With respect, Ron your cable in the pics is adjusted ( at the clutch ) all the way out.
This means inner cable is stretched and outer cable is compressed. I don't think you can make it work with that cable, need a new one...!!
O.K., just read that cable is new, if not Honda cable, chances are the inner cable free length is wrong...it needs to be a specific length....no-way should you need to turn the adjuster out all the way with a new cable...IMO.

Tower · « **Reply #15 on:** August 09, 2009, 09:15:34 AM »

@Spanner 1, note the extended spring and position of the lower clutch lever in Ron's picture. This indicates that the clutch cable is actuating the lever, yet the clutch is still not disengaging. Meaning, its probably not a problem with the cable, but rather inside the clutch. (Although the cable may still need to be looked at later.) When repeated turning in of the clutch adjusting bolt does not disengage the clutch, it indicates binding inside the clutch assembly.

@ron.cieri.313, I keyed in on your statement that the double rivetted plate was new. Unless you are replacing the old double plate, you must remove a disk to compensate for the extra thickness, hence my suggestion to remove the outermost disk to verify.

The problem of 180o rotation of the pressure plate is by far, the most common assembly error that gives these symptoms - especially when the bolts are not seating fully while being torqued in correctly.

MCRider · « **Reply #16 on:** August 09, 2009, 09:55:25 AM »

The last thing Tower said.

Its been a long time since I've had one apart. But i always marked the top of one of the bolt stands and its position relative to the part next to it. They are splined together and if you stack them up wrong the clutch won't work. The splines have to engage. There are many of then around the circumference of the part. Sorry I'm weak on the technical ID of the parts.

But they can go together 1 of 4 ways, since there are 4 bolt stands. Only 1 (or 2?) ways will work.

Hope it helps.

ron.cieri.313 · « **Reply #17 on:** August 09, 2009, 11:46:38 AM »

I'm going out to the garage to try out these GREAT ideas...my bolts to not seat on my clutch plate currently...what i mean by that is that not matter how much i tighten, it always seems i can tighten even more...consequently the springs get very compressed...that why i was confused on how these things can be tightened to a torque setting cuz once i tighten one, the other can be tightened more...is that what you are all referring to as not "seating"?

If thats the case, then the double plate I used is causing problems or my clutch plate could defintely need to be rotated 180 degrees.

With regards to the new double clutch plate B, I did remove one of the original metal plates when I added this one but it still might not have been enough.

...and with regards to the 180, I new that 2 of the ways of putting the clutch back were wrong, but I didn't think it matter which of the "correct" ways (when the plate mate properly) mattered.

...thanks, its 90 degrees out today so I'll be sweating but hopefully not cursing...thanks all...will let you know

ron.cieri.313 · « **Reply #18 on:** August 09, 2009, 12:34:05 PM »

Ah, question...when we say "pressure" plate are we referring to the lift plate shown in the pics below...i.e., the aluminum plate held by four bolts?...isn't this thing a square?

Current

Rotated (X now at the top; clutch basket held constant/not moved)

MCRider · « **Reply #19 on:** August 09, 2009, 12:52:35 PM »

The pressure plate has the 4 bolt stands on it. Towards the rear of the plate, the clutch center merges engaging the splines with those on the lifter plate. THis is the part that can only go one (or 2) ways. The clutch plates are smashed between the 2.

The lifter plate is just that, the lifter plate. Square with the bearing and 4 holes in it. It can go any way.

To reorient the pressure plate as tower suggests, you must remove not only the lifter plate, but the whole stack of plates. The pressure plate can only be moved once it is pulled out of the basket. You'll be jostling the whole stack of plates to rotate the pressure plate vis-a-vis the clutch center. You'll have the whole stack in your hands and you'll see where the male splines of the center merge into the female splines of the pressure plate.

This may not be your problem at all, but as Tower says it is the most common mistake in assembly, and there is not much else that can cause a problem.

ron.cieri.313 · « **Reply #20 on:** August 09, 2009, 01:33:27 PM »

Thanks MC...I rotated the lifter plate not the pressure plate...and of course it didn't work, will go back and try pressure plate that has the four post stands...that makes much more sense as I remember that working only 2 of 4 possible ways.

...well, guess I'll wait on that shower, damn its hot outside.

MCRider · « **Reply #21 on:** August 09, 2009, 01:39:07 PM »

Quote from: ron.cieri.313 on August 09, 2009, 01:33:27 PM

Thanks MC...I rotated the lifter plate not the pressure plate...and of course it didn't work, will go back and try pressure plate that has the four post stands...that makes much more sense as I remember that working only 2 of 4 possible ways.

...well, guess I'll wait on that shower, damn its hot outside.

YEah heat advisory here too, I'll work in the shop after sundown.

If this is indeed the problem, when you mate the clutch center with the pressure plate and the splines engage, it'll "click" and you'll go "dang!"

Tower · « **Reply #22 on:** August 09, 2009, 02:19:20 PM »

"Seating" refers to the pressure plate posts fully touching or seating against the clutch lifter plate. Once all four of these posts touch the lifter plate, the bolts can be correctly torqued - and yes this will significantly compress the springs.

To avoid problems of engaging, as spring tension increases, pull the pressure plate forward and engage it with the hub teeth while beginning the tightening sequence. If the hub-to-pressure plate were 90o off, the teeth would not mesh, but if they were 180o off, they would mesh at first, then get progressively more bound as you tightened the bolts. Note: you would definately crack and break off a lifter ear when tightening the bolts, if you do not mesh the hub teeth to pressure plate.

Also note, if you mounted the pressure plate 180o to the original orientation there is a slight danger of cracking the lifter plate when tightening - because the disks and plates could severly bind before allowing the lifter plate and pressure plate to seat properly - so be very careful.

"Dang" is right, @MCRider. When is fits right you will know it.

Edit: To make sure terminology is not the problem...
Using @cben750f1's diagram
Part#2 is the Clutch Centre, or Hub
Part#6 is the Clutch Pressure Plate, and
Part#7 is the Clutch Lifter Plate

MCRider · « **Reply #23 on:** August 09, 2009, 03:08:48 PM »

" Note: you would definately crack and break off a lifter ear when tightening the bolts, if you do not mesh the hub teeth to pressure plate." end quote

Yeah I forgot to mention things will break if its not done right.

ron.cieri.313 · « **Reply #24 on:** August 09, 2009, 07:52:59 PM »

Got it...I think...but just to be sure I've shown some pics of my disassembly below:

orientation as I just disassemble...so probably incorrect or off 180 degrees...you can see I mark a common post and hole combination with a white bread tie:

I believe the orientation I should have per you notes...boy, it seems like this shouldn't matter but now that i read the latest notes i guess this fit as to be just perfect.

...and one question, the entity on the right (with the post but no sides) is called the "pressure plate"?

Here's my array of friction discs

The disc on the far right of this pic is my larger B plate and ends up on the outside of the clutch basket.

Also, you can see my double center plate in the pic below...is this rotation doesn't work, me thinks I need to go back to one single plate in its place as it was when i original dissasmbled this monster.

...and finally, i finally understand how the post should "seat" against the lifter plate...see pic.

This grasshopper is humbled once again...hope to put together tomorrow night...pls stay tuned...thanks all

News:

Author Topic: Clutch Adjustment Sadness...cannot get it to disengage (Read 17139 times)