Topic: The Dreaded Clutch Plate Lifter Crack

[liPPy]

Well despite reading multiple threads & taking every precaution including:

1. Using a long case bolt to pull in the towers snug on initial assembly
2. Turning the bolts one quarter turn each before moving to the next, in a counter clockwise direction
3. Torquing in two steps, using a new calibrated torque, wrench all bolts to 4ft lb, followed by 6 ft lb
4. Whispering "Almost there, you f*cker" as three bolts of the bolts snugged up nicely to the correct final torque until...

...I managed to crack the plate. Bollocks!


It initially felt like I'd stripped the thread as all of a sudden it lost tension. Closer inspection revealed the damage.

Add me to the long list of owners who wonder why this particular component had to be made from cheese.

Springs were stock but I used new friction plates.

Are there any reliable aftermarket alternatives or do I have to pony up the $50 for a new OEM part (which I'm not convinced I won't contrive to ruin as well)??

Nothing on eBay right now. Does anybody have one spare??

Bike is a 750K8.

Thanks!

[Trav-i]

Sorry mate, to the best of my knowledge there are no aftermarket replacement plates, also they aren't really repairable either.  I would think your gonna have to pony up for a new one, I've been there too I broke one a year or so ago but I had an extra motor I stole the plate from.

Hope you can find one quick.

Travis

[the-chauffeur]

Yeah, done that twice on my K2.  They're even more fragile/brittle than the later ones . . .

I've kinda put paid to doing it again (or at least I haven't lost another) since I put penny washers between the fastener heads and the plate to spread the individual fastener load.

Bit late, but that might help in future . . .

[MCRider]

Sorry about that.

There is only one reason they break. The splines of the hub were not meshed in to the notches of pressure plate. I've never broken one, but I've seen several broken and learned the reason why and that saved me.

I have been participant in several threads where this was discussed, and have provided pictures. I'll repost them tonight. Keep watching eBay. One will turn up, people are parting these things all the time.

[Hinomaru]

Nothing on eBay right now. Does anybody have one spare??

Your 750 K8 clutch lifter plate was also used on the following models listed below. They all share the same Honda part number: 22360-300-010 and this could help you in locating a used replacement much sooner.

CB750F A MOTORCYCLE, JPN, VIN# CB750F-1000002 TO CB750F-1015054
CB750F A (76) MOTORCYCLE, JPN, VIN# CB750F-2000003 TO CB750F-2022317
CB750F A (77) MOTORCYCLE, JPN, VIN# CB750F-2100011 TO CB750F-2111489
CB750F A (78) MOTORCYCLE, JPN, VIN# CB750F-2200001
CB750K A (76) MOTORCYCLE, JPN, VIN# CB750-2540001 TO CB750-2575894
CB750K A (77) MOTORCYCLE, JPN, VIN# CB750-2700009 TO CB750-2729534
CB750K A (78) MOTORCYCLE, JPN, VIN# CB750-2800001
CB750K0 A MOTORCYCLE, JPN, VIN# CB750-1000001
CB750K1 A MOTORCYCLE, JPN, VIN# CB750-1044650
CB750K2 A MOTORCYCLE, JPN, VIN# CB750-2000001
CB750K3 A MOTORCYCLE, JPN, VIN# CB750-2200001
CB750K4 A MOTORCYCLE, JPN, VIN# CB750-2300001
CB750K5 A MOTORCYCLE, JPN, VIN# CB750-2500001

[liPPy]

Sorry about that.

There is only one reason they break. The splines of the hub were not meshed in to the notches of pressure plate. I've never broken one, but I've seen several broken and learned the reason why and that saved me.

I have been participant in several threads where this was discussed, and have provided pictures. I'll repost them tonight. Keep watching eBay. One will turn up, people are parting these things all the time.

Thanks MCR, but after carefully reading the threads from similar such mishaps I went out of my way to ensure everything was correctly meshed but perhaps I was still able to cock it up? I have a very healthy respect for my ability to make a pigs ear of even the simplest of tasks but I thought I had all of my bases covered on this one...

What I will be doing on the next install is setting the completed (& correctly meshed) assembly on the work bench and, using a vernier caliper, measuring the height of the "towers" on the pressure plate relative to the top of the clutch center as a quantitative reference.

l'll then measure this same height once components are in situ and before I start to tighten the bolts. So long as that matches my reference I should be good to go.

If any one else has any tips or better ideas feel free to chip in.

I'll also be buying new clutch springs. The old ones were in spec for height but I don't have a compression tester so perhaps some of their spring had already sprung? Who knows, but for the sake of $16 it at least takes one variable out of the equation.

It looks like Honda Parts Direct has the best pricing so yet another order will be winging it's way there soon.

In fact when I combine the shipping charges on all of the parts orders I've made, each one, naturally, being "the last one" I'll need to make (Ha - naive fool!) I could probably have bought another bike and had enough change for a couple of Gin & Tonics.

[MCRider]

You may not want to wait, but there is a whole clutch on eBay for $9.99, and many others for slightly more.  Search CB750 Clutch. Nothing more.

I'll be gracious if I'm corrected on this, But for now I'll stand on my position that the hub was not meshed into the pressure plate.

I'm glad to hear you are taking out the assembly. It should look like this when assembled.


When I disassemble them I mark the top of a post and the adjacent point of the hub, so that it goes back together properly. Like this, with a black sharpie or magic marker. There are 4 ways it can go. Only 1 (maybe 2) works.


What you need is a picture, without plates, of what it looks like when its not meshed. I thought I had it but can't find it. But i can take one of some spare parts.

Essentially, one will (almost) never break a plate when its meshed properly, no matter how ridiculous you get with tightening one bolt more than another etc.  When the plate is not meshed, one will (almost) always break the plate no matter how careful you are drawing down the bolts.

When the assembly is meshed properly there is no hesitation on drawing down the bolts. Zip, zip, criss cross. The plate draws the 4 posts up to its underside. The only resistance is progressive spring pressure. Finish off with the torque. Done, easy peazy.

OCICBW

[MCRider]

I found them:
here's how it should look. Simple install, no reisitance, nothing to sweat.

Here's how it looks when not right. Pieces rotated 90° in either direction:

Here's how it looks in the bike when its right:

Wrong:


If that's not your problem, then ignore these posts and I'll slnk intothe background. Have a nice day.   

[Patrick]

I have found that the lifter plate really only goes on one way. If you have it 90 or 270 degrees off then it can come down crooked. Try lining up the plate without the springs and you will see what I mean. Line it up, mark it or remember the orientation and then put in the springs and slowly tighten. Just tighten 1/2 turn at a time and pay attention to the torque. If one bolt get tight before the others you may have the orientation wrong.

I broke one lifter plate. That was how I broke it.

Patrick

[liPPy]

Thank you all for the time taken to reply, especially MC Rider. I think your response is the most thorough & detailed I have seen & surely warrants a move to the FAQ's?

As it happens I had already trawled ebay this afternoon and was able to pick up an entire assembly for $30 shipped.

I'll be sure to document round 2 of liPPy vs clutch so others may learn by my stupidity / MCR's genius.

[Magpie]

Many others, me included, have learned the hard way and keep an eye out for spare lifter plates. It's not an exclusive club and don't feel bad about it, except for the money part. MC has nailed the description of how to prevent it.
Cliff.

[1974cb550k]

I know this tread is old but still relevant. I fear that i have cracked my lifter plate as well. I was very careful in tightening 1/4 turns and in a x pattern but then i heard the crack. I assembled my plates and corks on the bench and then installed the whole unit as an assembly. I cant remember if it was oriented correctly. It all seemed to go together very easy. Is there a way to check without removing the basket assy. Thanx

[crazypj]

I've never broken one but I have seen dozens broken.
Even if lined up almost right there is enough slop for edge to catch and cause problem.
 I like to do it 'factory' and assemble on bench then fit clutch basket /hub as a unit with a spring installed.
(does anyone really think they did it service manual style when building hundreds a day?)

[MCRider]

I know this tread is old but still relevant. I fear that i have cracked my lifter plate as well. I was very careful in tightening 1/4 turns and in a x pattern but then i heard the crack. I assembled my plates and corks on the bench and then installed the whole unit as an assembly. I cant remember if it was oriented correctly. It all seemed to go together very easy. Is there a way to check without removing the basket assy. Thanx

As you can see in my first picture above, if the splines are aligned there is significantly more of the posts exposed on which to put the spring. Compare to pic #2 where the splines are not aligned, mush less post showing. That would be one way to tell without removing it.

When the splines are not aligned there is much more spring pressure on the lifter plate and that's what cracks it.  In fact there is so little post exposed and so much spring to compress i don't think it could be done no matter how careful you are. Then of course the clutch wouldn't work as the springs would be coilbound.

Bottom line though is that if the splines are aligned, the lifte plate goes on easily and while its good form to alternate the tightening of the spring bolts, if the splines are aligned you can get by without it. Or just do 2 at 180deg.  Zip them down 1 turn at a time then follow up with the others BAM you're done.

The difference is palpable.

[lucky]

Considering how many break and how many new ones are sold we should not run out of them.

If they just made it a simple steel stamping they would not get broken.

I think the trick is to  keep tapping them as you turn the bolts.

[MCRider]

Considering how many break and how many new ones are sold we should not run out of them.

If they just made it a simple steel stamping they would not get broken.

I think the trick is to  keep tapping them as you turn the bolts.

If the splines aren't lined up it doesn't matter what you make them out of. Alum, steel, titanium. They would either break, bend, or squeeze the springs to coilbind where the clutch won't work.

There are 4 ways to go, either 1 or 2 will work I forget which. So you have a 25 to 50% chance of getting it right by accident. IF its not right, its a no go.

[liPPy]

fyi on reading the thread through I realise I neglected to add an update.

The plate crack WAS due to misaligned splines ie my incompetence.

Using the information detailed in MCR's wonderful posts I was able to assemble the replacement without mishap.

[MCRider]

fyi on reading the thread through I realise I neglected to add an update.

The plate crack WAS due to misaligned splines ie my incompetence.

Using the information detailed in MCR's wonderful posts I was able to assemble the replacement without mishap.

Yay! I make some stuff up, but this subject i know pretty well. 

[CrankyOldGuy]

Back in ancient days I had one of the ears broken off by my local Honda mechanic, which I only found out about when I serviced the clutch a year or so later.  It was amazing how well the clutch worked with only three tabs .... I would have never known the difference if I had not taken it apart.  Being a "cheap" student at the time I took it to a local tractor repair shop that specialized in aluminum welding.  They welded on a new tab and machined it into the correct configuration.  It worked well and is still in the clutch assembly.  I will post a picture when I take the clutch apart for servicing.

All-in-all they can be rebuilt.

Harry O.

[MCRider]

Back in ancient days I had one of the ears broken off by my local Honda mechanic, which I only found out about when I serviced the clutch a year or so later.  It was amazing how well the clutch worked with only three tabs .... I would have never known the difference if I had not taken it apart.  Being a "cheap" student at the time I took it to a local tractor repair shop that specialized in aluminum welding.  They welded on a new tab and machined it into the correct configuration.  It worked well and is still in the clutch assembly.  I will post a picture when I take the clutch apart for servicing.

All-in-all they can be rebuilt.

Harry O.

Cool.    I'd bet it could work with 2, 180deg apart. never heard of one being fixed though. Amazing what a welder can do.

[1974cb550k]

Good news. I did not crack my plate, I removed and found it was 90% off. Put it all back together and BAMN! Got clutch Bad news I already got a new lifter plate. Im glad i found this post.

[Jiminy Indy]

Hah!! That will teach me to read these forums first instead of the manual.

Thanks MCRider, I'll follow your instructions this weekend.

[lucky]

Sorry about that.

There is only one reason they break. The splines of the hub were not meshed in to the notches of pressure plate. I've never broken one, but I've seen several broken and learned the reason why and that saved me.

I have been participant in several threads where this was discussed, and have provided pictures. I'll repost them tonight. Keep watching eBay. One will turn up, people are parting these things all the time.

That is not why the lifter plate breaks.
Most mechanics are very careful about lining up the splines etc.,.

They get  the hub all the way down and everything lined up but what happens is the lifter plate has to push the 4 springs down and sit on 4 posts.
The lifter plate as small ledges machined it it to center the lifter plate.
What happens is one of the four corners gets hung up on the little ledge and snaps off.
What I do is as it starts to get mostly tightened down is I keep tapping the edge lifter plate with a small hammer all around as I tighten the bolts . Just keep tapping it so it does not get hung up.

[MCRider]

Sorry about that.

There is only one reason they break. The splines of the hub were not meshed in to the notches of pressure plate. I've never broken one, but I've seen several broken and learned the reason why and that saved me.

I have been participant in several threads where this was discussed, and have provided pictures. I'll repost them tonight. Keep watching eBay. One will turn up, people are parting these things all the time.

That is not why the lifter plate breaks.
Most mechanics are very careful about lining up the splines etc.,.

They get  the hub all the way down and everything lined up but what happens is the lifter plate has to push the 4 springs down and sit on 4 posts.
The lifter plate as small ledges machined it it to center the lifter plate.
What happens is one of the four corners gets hung up on the little ledge and snaps off.
What I do is as it starts to get mostly tightened down is I keep tapping the lifter plate with as I tighten the bolts . Just keep tapping it so it does not get hung up.

It may not be the reason it breaks everytime. It most certainly is the reason it often breaks as many here who I have helped can attest.

MANY people here have attempted to tighten the lifter plate when the hub and pressure plate splines were not aligned.

[lucky]

Sorry about that.

There is only one reason they break. The splines of the hub were not meshed in to the notches of pressure plate. I've never broken one, but I've seen several broken and learned the reason why and that saved me.

I have been participant in several threads where this was discussed, and have provided pictures. I'll repost them tonight. Keep watching eBay. One will turn up, people are parting these things all the time.

That is not why the lifter plate breaks.
Most mechanics are very careful about lining up the splines etc.,.

They get  the hub all the way down and everything lined up but what happens is the lifter plate has to push the 4 springs down and sit on 4 posts.
The lifter plate as small ledges machined it it to center the lifter plate.
What happens is one of the four corners gets hung up on the little ledge and snaps off.
What I do is as it starts to get mostly tightened down is I keep tapping the lifter plate with as I tighten the bolts . Just keep tapping it so it does not get hung up.

It may not be the reason it breaks everytime. It most certainly is the reason it often breaks as many here who I have helped can attest.

MANY people here have attempted to tighten the lifter plate when the hub and pressure plate splines were not aligned.

I agree with you on that Mc Rider.

I try to hold the hub inwards so the hub and splines of the clutch plates and hub do not get undone.