Clutch adjustment - research and development

Mr. Wright

Guru
Supporting Member
I want you all to hold up on your comments on this, until I finish my research. I ran into a perfect opportunity to test some theories on clutch adjustments, on the nine plate easy pull clutch.
We all know how hard it is to get it adjusted so that you can find neutral. I have not found it a problem in my shop to do this, until this last bike. I installed a complete new clutch, and with the rod adjusted all the way in, not backing the rod off any, and adjusting the cable until there was absolutely no slack in the lever, the bike still pulls forward when you put it in gear.
I told the customer to ride it for a few days, and get it loosened up, and bring it back so I can do these tests. When he brought it back, I found that it had loosened up enough that the bike would sit there in gear, but we still couldn't get it into neutral.
This is the tests I've done to rule out some of these theories I've read about and people have said they have done.
First off I got out my grandfather's trusty fish scale, tied it to a rope to see how many pounds it takes to pull the lever. The scale says 20 lb.
IMG_20220617_091045.jpgIMG_20220617_090950.jpg
Next I took the ball ramps apart, clean them up, and attached three Earth magnets to the bottom plate. Then I set it on top of my vise, so that it when it was turned it would hit against the vice Jaws. Not that this is the actual distance that the cable would pull the ramp, but it is a distance that I can repeat for what I'm looking for.
IMG_20220617_094915.jpgIMG_20220617_095023.jpgIMG_20220617_095029.jpg
Next, using the stock 3/8 diameter ball bearings, I measured how far the plates moved apart, and then repeated the same test using the 13/32 ball bearings, which are the next size larger. Both ball bearings spread the plates exactly the same distance.
IMG_20220617_095523.jpg
Next, I took a set of regular ball ramps, and mismatched them to see what the lift would be. I did manage to gain .010 using the stock upper plate, with an easy pull bottom plate. Switching them the other way, it would not lift it at all. The problem is the slots on the two plates do not match up.
IMG_20220617_102258.jpgIMG_20220617_102120.jpgIMG_20220617_102149.jpg
I did reassemble the bike, using the easy pull bottom plate and a regular top plate. Readjusted the clutch, and when I adjust the slack out of the cable you can see that there's only a quarter inch of threads where there is normally half inch better.
IMG_20220617_104857.jpg
This did add 4 lb to the clutch handle pull, and did absolutely nothing on helping me find neutral.
Next we'll move to the handle to see if anything's loose up there. I am also in contact with HDM, on handle designs. This is because I have another bike sitting right next to it with a different style handle on it that has absolutely no problem getting into neutral.
More info to come as I do research
 
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Mr. Wright

Guru
Supporting Member
You know that the more I work on these bikes, the more impressed I am with the engineers that develop them. The only problem with the engineers was they were used to designing airplanes, and the specs on some of these parts are so close that it is just ridiculous.
I spent last evening on the phone with a couple people that I look up to that I believe are a lot smarter than me. And I believe I have found out what the problem is. But before I get into that, I still have to tear the other side down. But this morning I went back and redid a couple tests. One of the people I talked to was adamant that the 7/16 bearings was the better option. I want to say up front, do not put the 7/16 bearings in the regular pull ball ramps. The balls don't fit all the way to the bottom in the resting position and Ride along The edge. They do fit into the bottom on the easy pull ball ramps but as it ends its pull the ball rides up on the sides just at the end. And you only gain .0015 lift. When I put this side back together, I opted out on putting the 13/32 bearings back in only because they felt smoother than the 7/16.IMG_20220618_112000.jpg
Let me get the other side apart and I'll show you what we're all missing we're trying to figure this out. I actually caught this when I put the new clutch in, but it didn't register my brain is being a problem. More to come
 

Mr. Wright

Guru
Supporting Member
All right I now have a big headache. I have it figured out but it's going to be hard to explain. The first part of the post with the fish scales and all that was because we was looking to mismatch the plates to get more pull to separate the disc. Mismatching the plates will not work because they don't line up properly.
This whole thing has to do with a picture and one paragraph in the manual that talks about clutch dome height.
IMG_20220618_135422.jpg
What the engineers have decided is .050 is all that spring is supposed to move to work properly. So making that spring do more than that is not the answer. With the clutch adjusted properly, the rod backed off one quarter turn from touching, and all the slack taken out of the cable, we have .050.
IMG_20220618_141224.jpg
The engineers have figured that this was more than plenty of space to release them discs. In my shop I have always backed it off 1/8 of a turn, and with all the slack pulled out of the cable, I can create a dome height of .065.
More Gap less friction, should go right in the neutral. But it seems like when I put new clutches in, finding that sweet spot is hard. And we all know that, it's the reason for this research. The bike I'm working on not only could I not get it in neutral but I had to hold the brake to keep it from rolling forward, with a .065 dome height.
Like I said I saw the problem when I put the new clutch in but didn't see it as a problem actually was excited that I had more clutch thickness then what was in specs.
The old clutch I pulled out, measured 1.945, which was the worst one I've ever seen.
IMG_20220618_144233.jpg
The new clutch pack originally measured 1.985 maybe a little more, it is now measuring 1.98.
IMG_20220618_144454.jpg
So I measured through all my discs and brought the stack down to 1.975, which is within specs. Now I'll have to put this all back together and see where I'm at.
 

Jwooky

Well-Known Member
Following this. I installed the heavier pressure plate because my clutch was slipping after I did the engine work, even with a new clutch.

I also zeroed out the slop, and it still creeps and have to hit neutral before I stop.
 

Mr. Wright

Guru
Supporting Member
Ok, I'm back. Had to stop and actually do some work.
To explain what is happening when you have a slipping clutch, it's because your stack and pressure plate are shorter than spec's. You will find that the pressure plate will wear faster than the plates. So always replace your pressure plate, when doing a clutch job. When you bolt the pressure plate on, it is flat against the center part.
IMG_20220620_135832.jpg
If your stack is to tall, when you tighten up the pressure plate, your squeezing the plates to tight. And your.050 isn't enough to loosen the plates.
 

Th3InfamousI

Administrator
Staff member
Supporting Vendor
Well what stinks is it all started with a new clutch pack and who would think they need to measure it to double check.

The pressure plate is key, unfortunately I think people are throwing in new clutch packs unnecessarily. The original pressure plate that was the raw aluminum and not hardened wears and throws it all out of spec. It's probably the most important piece to replace when doing a clutch, if you get the hardened one you shouldn't have to ever replace it, but obviously check for wear anything can happen after 10-20k miles.

Easy to distinguish, original was aluminum in color the hardened pressure plates are brown in color.


As a note that .050 is the 9 plate setup, you need a little more lift with 12 disc. As you have to go further to get enough separation between more disk. It's one of the main reasons we only sell the 9 disc, it works better in the old style 12 plate ball and ramp as you seperate them further (neutral piece of cake). Also the steels on the 12 tend to wear way to quick, they had warranty returns on way too many and stacks just went to the dump. For some reason others still sell them, but if you actually run the numbers like Shannon did here and I've done in the past you can't argue. Just going with old shit and what was there before is never my response for something that clearly didn't work right. Especially since the answer was already available.

I actually recorded a video for folks to see these clutch measurements and discussing the pressure plate importance, but I just haven't had time to finish it. I'll see if I can get it off the cutting room floor soon.

Sent from my moto z4 using Tapatalk
 
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Th3InfamousI

Administrator
Staff member
Supporting Vendor
Here's a picture from the videos I was talking about on the difference between the two easy to distinguish. Brownish vs raw aluminum.



Notice the wear marks on the aluminum one? Very common this aluminum one actually came out of one of my bikes many years ago clutch was acting up. Well yea no shit there's ridges worn in on that plate you can feel with your hand.


Sent from my moto z4 using Tapatalk
 

Jwooky

Well-Known Member
For the record, I have the new anodized pressure plate too. It didn’t stop slipping until I called Baker and they offered me the thicker/ heavy spring
 

Mickmorris

mick
Supporting Member
Here's a picture from the videos I was talking about on the difference between the two easy to distinguish. Brownish vs raw aluminum.



Notice the wear marks on the aluminum one? Very common this aluminum one actually came out of one of my bikes many years ago clutch was acting up. Well yea no shit there's ridges worn in on that plate you can feel with your hand.


Sent from my moto z4 using Tapatalk
Jeez
 

Mikeinjersey

Active Member
Well what stinks is it all started with a new clutch pack and who would think they need to measure it to double check.

The pressure plate is key, unfortunately I think people are throwing in new clutch packs unnecessarily. The original pressure plate that was the raw aluminum and not hardened wears and throws it all out of spec. It's probably the most important piece to replace when doing a clutch, if you get the hardened one you shouldn't have to ever replace it, but obviously check for wear anything can happen after 10-20k miles.

Easy to distinguish, original was aluminum in color the hardened pressure plates are brown in color.


As a note that .050 is the 9 plate setup, you need a little more lift with 12 disc. As you have to go further to get enough separation between more disk. It's one of the main reasons we only sell the 9 disc, it works better in the old style 12 plate ball and ramp as you seperate them further (neutral piece of cake). Also the steels on the 12 tend to wear way to quick, they had warranty returns on way too many and stacks just went to the dump. For some reason others still sell them, but if you actually run the numbers like Shannon did here and I've done in the past you can't argue. Just going with old shit and what was there before is never my response for something that clearly didn't work right. Especially since the answer was already available.

I actually recorded a video for folks to see these clutch measurements and discussing the pressure plate importance, but I just haven't had time to finish it. I'll see if I can get it off the cutting room floor soon.

Sent from my moto z4 using Tapatalk
Just looking for a little clarity. Are you recommending that if you replace the 12 disc for a 9 disc there is no reason to change the ball and ramp and in fact it works better ? Thanks
 

Mr. Wright

Guru
Supporting Member
Just looking for a little clarity. Are you recommending that if you replace the 12 disc for a 9 disc there is no reason to change the ball and ramp and in fact it works better ? Thanks
The ball and ramp will not make any difference between the 12 and 9 plate clutch pack. When they came out with the 9 plate clutch, they cut longer grooves to it easier to squeeze the handle. If your still man enough, to squeeze the clutch, there is no reason to change it out.
 
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