Author Topic: 750k clutch spring plate (Read 6414 times)

surein · « **on:** March 17, 2012, 01:05:53 PM »

anyone know where I can find one? Just cracked the corner

thanks

nancy · « **Reply #1 on:** March 17, 2012, 08:05:23 PM »

You mean lifter plate?
http://www.davidsilverspares.co.uk/CB750K1-FOUR-1971/part_104558/

surein · « **Reply #2 on:** March 18, 2012, 12:24:56 AM »

yes! thank you!!

surein · « **Reply #3 on:** March 18, 2012, 08:33:48 AM »

Honda!? I'll ask.
any idea how I can look up the part number?

surein · « **Reply #4 on:** March 18, 2012, 09:21:21 AM »

thanks so much!

mycb750k6 · « **Reply #5 on:** March 18, 2012, 09:53:36 AM »

Don't forget that the bolts on these must be loosened and tightened little by little. If you tighten or loosen one bolt all the way before the others, that corner will break.

surein · « **Reply #6 on:** March 18, 2012, 12:52:04 PM »

*blush* that's how I got into this predicament

The bearings/radial ball - do I just tap it out to separate?

mycb750k6 · « **Reply #7 on:** March 18, 2012, 01:23:56 PM »

You should not need to replace the bearing unless you want to. Any replacement clutch plate will have a bearing in it and they are usually good. If necessary, heat the aluminum and tap out the bearing if necessary. It's a press fit. These plates are on ebay all the time for cheap. When tightening down, I would do 1/2 rotation at a time with these bolts. Go easy with it. You won't break another I'm sure.

Pecantree · « **Reply #8 on:** March 18, 2012, 01:31:09 PM »

Just replaced the bearing in one. It was so cool. Heated the lifter plate with a heat gun, holding the plate with pliers.
The bearing just plopped out. No tapping, or pounding!
Good luck.
Steve

MCRider · « **Reply #9 on:** March 18, 2012, 01:38:36 PM »

Quote from: surein on March 17, 2012, 01:05:53 PM

anyone know where I can find one? Just cracked the corner
thanks

Did you have the clutch apart? The main reason these break is that the splines in the hub did not line up with the notches in the pressure plate. There are 4 ways it can go. Two of them will work, the other 2 will almost certainly end up with a broken lifter plate.

Yes its true you must follow procedure in tightening the bolts. But if the splines aren't lined up it will still break.

surein · « **Reply #10 on:** March 18, 2012, 02:09:20 PM »

yes I took the clutch apart.
what do you mean the splines didn't line up with the pressure plate? The hub has the bolt locations which guides the plate to location. I wasn't aware of alignment.

surein · « **Reply #11 on:** March 18, 2012, 02:11:55 PM »

Quote from: mycb750k6 on March 18, 2012, 01:23:56 PM

You should not need to replace the bearing unless you want to. Any replacement clutch plate will have a bearing in it and they are usually good.

The new plate is sold separately from the bearing and ebay only sells the entire hub/kit. shipping to Canada is atrocious

MCRider · « **Reply #12 on:** March 18, 2012, 02:19:59 PM »

Quote from: surein on March 18, 2012, 02:09:20 PM

yes I took the clutch apart.
what do you mean the splines didn't line up with the pressure plate? The hub has the bolt locations which guides the plate to location. I wasn't aware of alignment.

As i mentioned there are 4 possibilites, as you can see. There are the 4 bolt lugs and 4 holes and you can pick any one of 4 positions. Only 2 of those positions will lead the splines into alignment. 2 other positons and the splines will stand on top of the notches and will not "sink in". Then when you go to tighten it up, snap! The protocol is to mark the top of a stud post and an adjacent spot on the pressure plate, so it goes back together the way it came apart.

Pictures are coming.

MCRider · « **Reply #13 on:** March 18, 2012, 02:29:11 PM »

Wrong

Right

Example of marking a post and the pressure plate

Wrong

Right

You may have had it right all along in which case, just file this away for another time.

surein · « **Reply #14 on:** March 18, 2012, 03:00:12 PM »

son of a ..!
wish I had known about that. However the entire hub wouldn't have fallen in properly and sit flush if I hadn't aligned it correctly - right?
I also think a spring was caught between the plate and the pillar when I was tightening cause I remember hearing a slight twang.

thanks so much for the heads up.

MCRider · « **Reply #15 on:** March 18, 2012, 03:10:23 PM »

Quote from: surein on March 18, 2012, 03:00:12 PM

son of a ..!
wish I had known about that. However the entire hub wouldn't have fallen in properly and sit flush if I hadn't aligned it correctly - right?
I also think a spring was caught between the plate and the pillar when I was tightening cause I remember hearing a slight twang.

thanks so much for the heads up.

I've never tried to tighten one that was misaligned, so I don't know for sure what it looks like installed. I've just seen it on others and customers bikes back when i was in a shop. And they tried a DIY on the clutch and couldn't figure out why they broke the lifter plate.

You had a 50/50 chance to get it right, so maybe its OK. And it was just a process issue.

MCRider · « **Reply #16 on:** March 18, 2012, 04:14:20 PM »

The more i think about it, I think the clutch hub will bolt up to the mainshaft in the clutch basket, and the pressure plate with the 4 bolt lugs on it, will float around, thereby masking the issue of whether or not the splines are lined up. Otherwise the issue of trying to tighten the lifter plate while the splines are misaligned wouldn't be an issue.

In other words the assy is not foolproof, so you may want to check. If you pull the 4 bolt lugs to you you'll feel the splines engage into the notches, then you'll be ready to tighten the 4 bolts. If not, you may want to un nut the hub and pull everything out and make sure it looks like my "right" picture. Mark it, and reassemble. I know that's unpleasant as that nut with the 4 notches isn't fun to work with.

surein · « **Reply #17 on:** March 18, 2012, 04:26:11 PM »

Thanks! I'm going to take everything out and try different alignments just so I know what feels right before I commit. It'll be two weeks before I get a new lifter plate. Wish I could weld the small crack and start riding

MCRider · « **Reply #18 on:** March 18, 2012, 04:29:40 PM »

Quote from: surein on March 18, 2012, 04:26:11 PM

Thanks! I'm going to take everything out and try different alignments just so I know what feels right before I commit. It'll be two weeks before I get a new lifter plate. Wish I could weld the small crack and start riding

Good luck, let us know.

surein · « **Reply #19 on:** April 06, 2012, 11:07:14 AM »

finally got the plate - well it was from a 78 F so I had to swap out the bearing since the F did not have the pin on the engine side.
Question - Does the plate get tighten all the way in? I am not sure about how the clutch works. The clutch lever pulls the cable which rotates and pushes the plate in... this is where it gets confusing to me. By tightening the plate all the way in, does that not engage the clutch? Here's a pic

MCRider · « **Reply #20 on:** April 06, 2012, 11:14:02 AM »

Yes the lifter plate is tightened down snug against the pressure plate posts. Probably use 8ft lbs or so. So the lifter plate and the pressure plate become as one separated by the 4 posts. Compressing the springs to a predetermined amount. Determined by the height of the posts. The clutch disc pack is now fully engaged, the default position.

When you pull the lever, the triple ball ramp lifter pushes against the lifter plate in towards the engine, compressing the springs. This pushes the pressure plate away from the hub, which can't move, thus opening the disc pack and allowing it to disengage.

Letting the lever out, the springs push outwards on the bottom of the lifter plate, dragging the pressure plate with it and compressing the disc pack back into engagement.

Your install looks complete and proper. The lifter plate couldn't have settled that nicely if the hub splines were mis aligned to the pressure plate notches.

surein · « **Reply #21 on:** April 06, 2012, 11:57:16 AM »

I followed your help with alignment - marked the hub so the hub splines lined up. Thanks for that tip!
I assembled the rest but now it feels like the clutch is just engaged. Might just be the cable..

thanks again

MCRider · « **Reply #22 on:** April 06, 2012, 12:38:58 PM »

Quote from: surein on April 06, 2012, 11:57:16 AM

I followed your help with alignment - marked the hub so the hub splines lined up. Thanks for that tip!
I assembled the rest but now it feels like the clutch is just engaged. Might just be the cable..

thanks again

Apologies in advance if I'm telling you what you already know.

First, loosen the cable to the max at the cover where it enters the engine, and at the handlebar.
Then adjust the lifter per the manual. Most important part.
Then the cable at the engine.
Then fine tune at the handlebar.
Should work fiine.

surein · « **Reply #23 on:** April 07, 2012, 10:08:02 AM »

thank you sir cause I know nothing.
I adjusted the screw as per the manual (1/4 turn less of full resistance) and tightened the cables up and even tried a few different ranges but I can't engage the clutch. The hand lever has no resistance and I can't get the bike in gear.

You think the F plate or my bearing installation is the cause?

MCRider · « **Reply #24 on:** April 07, 2012, 10:16:15 AM »

Quote from: surein on April 07, 2012, 10:08:02 AM

thank you sir cause I know nothing.
I adjusted the screw as per the manual (1/4 turn less of full resistance) and tightened the cables up and even tried a few different ranges but I can't engage the clutch. The hand lever has no resistance and I can't get the bike in gear.

You think the F plate or my bearing installation is the cause?

If it worked before and you were able to adjust it at will, then you have to suspect whatever has changed. The plate or the bearing.

I'll look at some fishies, but it won't be till much later today.

surein · « **Reply #25 on:** April 07, 2012, 04:55:54 PM »

I have this much play room - is it normal? The triple ball ramp has to be tight between the plate and the cover for it to compress the springs - correct? I find that now when I tighten the adjusting screw, I can screw it all the way in not leaving any room for the lock nut.

MCRider · « **Reply #26 on:** April 07, 2012, 05:07:07 PM »

i was wondering about that. Something's wrong (duh). Wish I were there.

The lifter plates all carry the same part number.

Do you have #12 installed?

http://www.motogrid.com/pages/OemParts?aribrand=HOM#/Honda/CB750K2_A__MOTORCYCLE%2c_JPN%2c_VIN%23_CB750-2000001/CLUTCH/CB750K2-JPN-A/2Y143410E14341009B

surein · « **Reply #27 on:** April 07, 2012, 05:47:49 PM »

#12 was already installed in the bearing. The F plate I got had a different #12 than my original so I had to switch the bearing. I didn't even know they could be separated.

This picture shows the #12 on the #19 bearing or am I missing something?

MCRider · « **Reply #28 on:** April 07, 2012, 06:06:31 PM »

Yah I had to ask. It looked like it was there in your previous picture, and i wasn't really in tune to it beingremovable either.

Looking at that picture, I can't help but think the lifter plate is further down in the hub than I remember it should be. That would indicate the splines/notches aren't engaged. Can you grab the lifter plate and turn it?

I'm really reaching here.

surein · « **Reply #29 on:** April 07, 2012, 07:06:10 PM »

The lifter plate is actually sitting on the cross sections of the hub - is that too low? I cant really see the posts so that's my gauge. Yes the plate and the hub does rotate.

I won't be able to work on this tomorrow but I will take the entire clutch apart and see if I missed anything; not that I have an extra parts lying around.

I appreciate all your help Rider - thanks again

MCRider · « **Reply #30 on:** April 07, 2012, 08:24:32 PM »

i'M A LITTLE GROGGY. That wasn't the best test, it will rotate good or bad. I'll pop mine off tomorrow and see what's the good test. Take some pictures etc. I think something is wrong with the assy though.

surein · « **Reply #31 on:** April 07, 2012, 08:41:22 PM »

haha! no worries and thanks again. Have a good night

MCRider · « **Reply #32 on:** April 08, 2012, 09:36:56 PM »

So here's what i found:
First do you have all 3 parts of the lifter?

Here you can see how deep in the lifter plate is when properly seated:

It measures about 4.5mm deep, maybe 5mm.

That picture also shows that a screwdriver will drop behind the lifter plate. You mentioned your lifter plate is down on the castings of the hub. This is incorrect, mine was proud of the castings.

Grabbing the lifter plate thus, you should not be able to turn it either way. My bike is on the centerstand and in neutral.

surein · « **Reply #33 on:** April 11, 2012, 03:12:42 PM »

First off that's the cleanest bike i've ever seen!
Second - nice colour on the frame
Third - did I mention how clean your bike looks?

Ok so back to my headache - I finally got a chance to get into it. What I find is that the press plate with the 4 posts falls back into the engine once I assemble the unit, and the teeth slightly catches the plates not allowing it to return. This cause my pressure plate to line up incorrectly. Is that normal? I do have the #15 washer so not sure what I'm missing..

Plus my clutch does rotate freely making it difficult to tighten the lock nut

Thanks so much for opening up your clutch Rider

CrankyOldGuy · « **Reply #34 on:** April 11, 2012, 03:51:14 PM »

Just noticed this thread. Back in ancient times when my cases on the 750K1 had to be replaced, the Honda mechanic must broken one of the clutch plate ears when reassembling the engine. I discovered this because he forget to put a handful of o-rings in the rebuild ... leaked oil like a sieve. I had a local machine shop, which specialized in aluminum welding (i.e. highway overhead signs), build and machine a new ear on. It looked great and still works fine.

Never thought to buy a new one ... but at that time I was ticked off at the dealership

Harry O.

surein · « **Reply #35 on:** April 11, 2012, 05:44:43 PM »

haha! Harry O.
This all started so I can get a bit more friction zone.

I finally finished and rode around the block. Stalled it once cause I have to get used to the new clutch. Will tweak the cable to get it just right but it feels so much smoother.

Can't believe I fixed it! I had to make sure the pressure plate with the posts didn't fall back when I was screwing the lifter plate. Once the lifter plate was on tight everything else fell into place.

Now I have to fix my brakes *gulp*

Thanks again!!

MCRider · « **Reply #36 on:** April 11, 2012, 06:35:12 PM »

Quote from: surein on April 11, 2012, 05:44:43 PM

haha! Harry O.
This all started so I can get a bit more friction zone.

I finally finished and rode around the block. Stalled it once cause I have to get used to the new clutch. Will tweak the cable to get it just right but it feels so much smoother.

Can't believe I fixed it! I had to make sure the pressure plate with the posts didn't fall back when I was screwing the lifter plate. Once the lifter plate was on tight everything else fell into place.

Now I have to fix my brakes *gulp*

Thanks again!!

That sounds Great! Hope i helped. The condition you cited, the pressure plate with the posts falling back into the basket is typical. Maybe not in this thread but in other threads about this same topic, the trick to that has been mentioned by others. You should thread a longer 6mm bolt into one of the posts. Using it as a handle, you can pull the pressure plate into its spline/notch alignment. Then thread in the other 3 bolts till they are snug enough to hold it where it needs to be. Then thread out the handle bolt and thread in the 4th bolt. Then finish up tightening the 4 bolts in rotation.

As to my bike, a 72 CB750K, thank you for the compliments. After having been used and abused for 23 years, becoming hugely filthy on many occasions, it is being rebuilt from scratch. Hence the cleanliness. I invite you to peruse my build thread, the link is in my signature.

I needed to pull the cover off the clutch to see if I had replaced the lifter with a low mileage one I had bot. I had. But i was ignoring helicoiling a stripped hole, so I'll do that.

surein · « **Reply #37 on:** April 12, 2012, 04:16:00 AM »

Thanks for everything Ron. I have the Clymers and My CB750 as reference to these little mods but nothing beats a bit of live help.

Great build thread. You have to be the most patient man in the world.
Very inspiring

Good luck and take care till next time

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Author Topic: 750k clutch spring plate (Read 6414 times)