Author Topic: 750k clutch spring plate (Read 6415 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.

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Author Topic: 750k clutch spring plate (Read 6415 times)