Author Topic: cant pull clutch lever? (Read 3583 times)

zeus87 · « **on:** March 10, 2008, 01:44:17 PM »

Hello, just installed new set of friction discs on my 1978 cb750k. After install I cant squeeze the clutch lever, it feels like a rock? anyone know what i did wrong? PLEASE HELP!! THANKS!

seaweb11 · « **Reply #1 on:** March 10, 2008, 01:48:19 PM »

Open it back up and have a look.

Take a photo, and perhaps we will see the problem.

zeus87 · « **Reply #2 on:** March 10, 2008, 02:19:51 PM »

here ya go....grrr.. thanks

mystic_1 · « **Reply #3 on:** March 10, 2008, 02:25:43 PM »

Did you back off the clutch arm adjusting screw before you put the cover back on? Since you've replaced the friction discs, the clutch pack is now wider than it used to be and all adjustments need to be re-performed. Make sure to do them in the proper order (loosen everything, then adjust clutch lifter arm, then clutch cable lower adjustment, then clutch cable upper adjustment).

mystic_1

zeus87 · « **Reply #4 on:** March 10, 2008, 02:29:38 PM »

that flat head bolt, with the nut to lock it? Yes...i tightened it untill it was no longer loose, then put the nut on to lock it in place.. thanks..im still trying to figure it out, i dont want to squeeze the clutch to hard and break something.

scondon · « **Reply #5 on:** March 10, 2008, 02:31:48 PM »

The center lock nut for your clutch adjuster seems to be missing in your top picture. Once everything is assembled use a screwdriver to back off that center adjuster and then screw it back in until "slight" resistance is felt. Back off adjustment 1/4-1/2 turn and tighten the lock nut.

If you tighten the center adjuster until it's tight, your clutch is locked in a fully disengaged state.

333 · « **Reply #6 on:** March 10, 2008, 02:40:47 PM »

Not related to your problem, but clean that surface where the clutch cover gasket sits.

mystic_1 · « **Reply #7 on:** March 10, 2008, 02:42:55 PM »

If you look close, the clutch cover screws aren't in all the way, think that first pic just has things loosely fitted. If that nut were omitted, the clutch arm would fall off the end of the shaft, yes?

Zeus, the clutch adjustment procedure is in Section 4 of the CB750 Service Manual available here:

http://forums.sohc4.net/index.php?topic=17788.0

Look at page 39 of the PDF, which is page 183 of the manual.

Good luck!

mystic_1

zeus87 · « **Reply #8 on:** March 10, 2008, 02:47:13 PM »

dirty because i removed cover, yes it will be cleaned...

I used that nut....still nothing, it looks loose because i just through it back together for a picture, hoping that maybe that flathead had to be in a certain position, also i left the nut off the "arm" because im holding it there while trying to engage the clutch.

Ps: i can move the friction disks in the basket a little bit, this is normal correct?

mystic_1 · « **Reply #9 on:** March 10, 2008, 02:51:38 PM »

When the clutch center and clutch springs are in place, and the clutch cover/lifter assy removed, you should not be able to wiggle the plates. The clutch should be fully engaged in this scenario. Put it in gear, and you should not be able to rotate the rear wheel.

If this is not the case, some thing's reassembled wrong.

mystic_1

zeus87 · « **Reply #10 on:** March 10, 2008, 02:56:52 PM »

with it in gear, i can roll it. oh boy!

scondon · « **Reply #11 on:** March 10, 2008, 03:00:12 PM »

Did you back that center nut all the way out until it is loose? Clutch should bite then.

mystic_1 · « **Reply #12 on:** March 10, 2008, 03:03:47 PM »

Check to see that the splines of the clutch pressure plate are properly aligned with the splines in the steel plates of the clutch pack (steel plates). If these are misaligned than when you try to slide the clutch center into place, it's not going all the way in. When installing the clutch center you should be able to slide it all the way in until the clutch plates make contact with each other, ie the fully closed position.

I remember getting tripped up by this before.

Take a look at the Parts Manual, section 1, page 24 of the PDF which is page 30 of the manual. The splines on the clutch center, item 2, need to align properly with the matching splines on the clutch pressure plate, item 7. Try several different alignments of the parts until it drops into place. It'll be noticeable when it does.

mystic_1

Edit: Oops forgot you have a K8. My references were to the earlier model manuals.

You want to look at the K8 F3 Manual, page 98 of the PDF (page 8-3 of the book). This exact problem is described there.

zeus87 · « **Reply #13 on:** March 10, 2008, 03:08:15 PM »

took the springs out...still can push it in gear. Im going to pull the plates, i will snap a few shots..ill post in less than 10 mins

mystic_1 · « **Reply #14 on:** March 10, 2008, 03:19:28 PM »

Once the springs are out, the clutch is "disengaged", so you will be able to roll it at that point. Your problem is that it rolls with the springs installed

Check the edit to my previous post, I'd bet dollars to donuts that's your problem.

mystic_1

zeus87 · « **Reply #15 on:** March 10, 2008, 03:32:22 PM »

ahhh thats the daddy!! Thanks dude!...hey just a quick Q. this washer doesnt seem right...the one the screwdriver is pointed to...it goes over the splines than just falls off of them and sits loosely?

ps: is this why i had to put the stock springs back in? no matter how hard i pushed, the ebc springs would not go...just to hard. now you think they will go?

THANKS AGAIN!!!!

mystic_1 · « **Reply #16 on:** March 10, 2008, 03:40:40 PM »

Yeah I'm pretty sure that's normal - I remember mine being the same.

I believe that washer's only purpose is to shim the clutch center so that it sits right distance out on the shaft. I remember sweating about that one myself when I first took my clutch apart.

Re the springs, you'll probably find that the clutch works much better when properly assembled

I'd say go ahead and try the new springs when you button it all back up.

Glad I could help

mystic_1

Tower · « **Reply #17 on:** April 12, 2008, 06:20:11 PM »

@zeus87, I just noticed this posting with your picture of the clutch plates. (thanks to mystic_1's link) Which direction does your clutch spin? It should spin counterclockwise. Those friction discs look like they're in backwards. What I mean is that the oil should be flung outward from the clutch centre as it spins, along the grooves. Therefore the grooves should help fling the oil out. With the groves facing in the opposite direction, that will be more difficult.

greenjeans · « **Reply #18 on:** April 12, 2008, 07:25:37 PM »

Mine ('72 CB750K) spins clockwise if you rotate the crank clockwise....hope that's correct.
So, he's got the discs in the correct way ?

dpen · « **Reply #19 on:** April 12, 2008, 07:50:23 PM »

this may sound stupid but...did you fit the same number of plates that came out & are they in the same order?

The first time I did mine I had to go trial & error as I put it back together according to the manual & had the same trouble as you - turns out mine was a bastard clutch & I made the assumption that it was standard

zeus87 · « **Reply #20 on:** April 12, 2008, 08:37:09 PM »

hmm... clutch is working awesome, i matched disks to what they were when they came out. I hope all is well internally, it sure functions great. Thanks

Tower · « **Reply #21 on:** April 12, 2008, 08:44:21 PM »

Right. If the crankcase spins clockwise, then the main transmission shaft will spin clockwise because they are connected by the primary chain. Then, the clutch being on the main transmission shaft, should spin clockwise. Following that through...the main shaft via gearing, spins the countershaft in the opposite direction, which then via gearing, spins the final driven shaft in original (back to clockwise) direction, which spins the rear wheel, via chain in the same (clockwise) direction.

The clutch disc oil grooves should slant so that the leading end is the inside, and the trailing end of the groove, is on the outside of the disc. If this is true of your bike, then the clutch disk grooves in the picture are correct.

Its been at least a year since I worked on any clutches - someone tell me if that`s right, please!

zeus87 · « **Reply #22 on:** April 17, 2008, 10:05:27 PM »

hmmm, you have me thinking..I just got it out for a real ride (more than around the neighborhood) and noticed my clutch is deffinetly slipping. 3000 and above with some real acceleration and i rev up about 1000 rpms and then back down... Now i have the adjusting screw (motor) backed out 1/4 turn from resistance, and the cable adjusted with about a 1/4 inch of play. I noticed it is hard to find neutral with this setting. If i turn the screw in all the way (until full resistance but not beyond) i have a much better clutch resulting in easier neutral finding. What do you think is going on here? EBC plates, and heavy duty springs. Thanks in advance! p.s. im using castrol 20/50 motorcycle oil (located in florida)

zeus87 · « **Reply #23 on:** April 18, 2008, 09:04:41 AM »

nothing?

Tower · « **Reply #24 on:** April 18, 2008, 12:21:00 PM »

These are symptions that the adjustment needs a bit more tweeking. Remember to always turn out the adjusting bolt after loosening the lock nut, so that the adjustment can begin with a definite baseline, before starting to turn in the bolt.

And do the final tweeks at the handlebar.

The clutch as its configured has a very close tolerance, that's what's makingit hard to fine tune.

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Author Topic: cant pull clutch lever? (Read 3583 times)