Clutch pack durability

5913 Views 12 Replies 4 Participants Last post by Sic2JZ, 23 d ago

Mattx852

Discussion Starter · Apr 16, 2022

I rebuilt the clutch master and slave on my 07 1kRR because the slave was leaking a little fluid. After it was bled I went on a nice 100 mile ride. Didn’t notice anything wrong. Today I took a ride and the first time I really got on the throttle the clutch slipped. It seemed that it was grabbing in low gears but in any gear above 3 it would slip bad whenever throttle was applied quickly. I did some investigating and found the master was pulling in fluid very slowly when bled, but the level in the reservoir did not rise when pulling the lever (should rise a couple millimeters until the piston cup is over the reservoir port). So I concluded that a piece of crud was blocking the pinhole in the master cylinder creating a one way check valve. It would let fluid in slowly but not out at all. As I was riding the bike the clutch circuit had a little pressure as if I was holding it down a little. Same exact thing as not having enough clutch cable free play. My question is, how much damage do you think I did to my clutch pack? The 100 mile ride I went on I didn’t notice the clutch slipping at all. Today the ambient temp was way hotter so the fluid probably expanded causing pressure. I did a few test pulls in 3rd gear to try to figure out what was going on. It would surge from about 4K to 7k before I got off it. Just cruising it felt fully engaged, but it still could have been slipping slightly. Today I rode about 10 miles like that taking it easy and staying in low gear to avoid slipping the clutch too much. Do you guys think I toasted my clutch or not likely? I slip the clutch on my stunt bike hundreds of times a day but that’s quick and controlled. I’m just worried I might have decreased the life of the clutch pack. Thanks in advance for any input. Love hearing from you guys 🤙🏼

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TurboDave

· #2 · Apr 20, 2022

I assume you've cleared the expansion hole in the master? Your lever allows the master piston to extend past the hole?

Its hard to say what's going on without seeing how your clutch pack is assembled. I've seen several 04-07 bikes with "new" slipping clutches and it ends up being an incorrectly assembled clutch pack. Most of the time people don't realize there is a skinny friction plate that goes in the back of the clutch and the judder springs go with it. I've seen frictions left out even.

If you know it is all in order then you likely have warped and burnt steels or cracked frictions. Loose spring retainer bolts or cracked spring. Or worse, a cracked spring perch or basket. You might as well get a repair manual and start digging and see what's going on in there. Its not too difficult and would be good to double check everything. Check your steels on a flat surface for warpage. One steel in the back should have a little warpage on purpose. When in doubt replace them all.

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Mattx852

Discussion Starter · #3 · Apr 21, 2022

TurboDave said:
I assume you've cleared the expansion hole in the master? Your lever allows the master piston to extend past the hole?

Its hard to say what's going on without seeing how your clutch pack is assembled. I've seen several 04-07 bikes with "new" slipping clutches and it ends up being an incorrectly assembled clutch pack. Most of the time people don't realize there is a skinny friction plate that goes in the back of the clutch and the judder springs go with it. I've seen frictions left out even.

If you know it is all in order then you likely have warped and burnt steels or cracked frictions. Loose spring retainer bolts or cracked spring. Or worse, a cracked spring perch or basket. You might as well get a repair manual and start digging and see what's going on in there. Its not too difficult and would be good to double check everything. Check your steels on a flat surface for warpage. One steel in the back should have a little warpage on purpose. When in doubt replace them all.
View attachment 264850

I cleared the expansion hole with some brake cleaner and compressed air and flushed out the system with brand new Motul RBF600. The clutch is grabbing just fine. Even at medium RPM in 6th gear, if I crank on the throttle, the revs stay right where they are supposed to. Probably took some life off the clutch but it feels fine ever since I cleared the expansion hole.

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09_Blade

· #4 · Apr 21, 2022

When you do wear out the clutch, swap in a Trac King kit from APE and don't ever worry about burning the clutch. I've been heavily abusing the clutch with hard launches from 6k and it's practically bulletproof. No slipping even with a ~90 ft-lb torque built motor and stock clutch springs.

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Mattx852

Discussion Starter · #5 · Apr 21, 2022

09_Blade said:
When you do wear out the clutch, swap in a Trac King kit from APE and don't ever worry about burning the clutch. I've been heavily abusing the clutch with hard launches from 6k and it's practically bulletproof. No slipping even with a ~90 ft-lb torque built motor and stock clutch springs.

Thanks for that info. I’ve been thinking about installing a new clutch pack at 30k as preventative maintenance. I see no point in waiting until parts break to fix them. They only have the fibers for the 04-07. I should be fine with OEM steels when it’s time right?

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09_Blade

· #6 · Apr 22, 2022

Mattx852 said:
Thanks for that info. I’ve been thinking about installing a new clutch pack at 30k as preventative maintenance. I see no point in waiting until parts break to fix them. They only have the fibers for the 04-07. I should be fine with OEM steels when it’s time right?

Yes. OEM steels are fine. Make sure to measure the pack height before install.

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Mattx852

Discussion Starter · #7 · Apr 22, 2022

09_Blade said:
Yes. OEM steels are fine. Make sure to measure the pack height before install.

Honda doesn’t give a stack height spec in the 04-07 service manual which I think is why so many people go OEM. Idk how else I would go about it…. Any thoughts? Or should I just slap it in and if nothing slips, drags, or shudders assume it’s fine?

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09_Blade

· #8 · Apr 22, 2022

I don't have a manual handy, but it should give a thickness wear limit for the individual plates. If you add them up that should approximate your pack height.

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Mattx852

Discussion Starter · #9 · Apr 22, 2022

09_Blade said:
I don't have a manual handy, but it should give a thickness wear limit for the individual plates. If you add them up that should approximate your pack height.

You’re right. Considering the kit is specifically made for the bike I’d expect the stack height to remain the same but I guess it’s never bad to double check. Also, there are two friction plates that have a bigger inner diameter. I assume this APE kit is similar correct?

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09_Blade

· #10 · Apr 22, 2022

Yes. The APE kit comes with exactly what you need. Unless you run an aftermarket clutch (Suter, yoyodyne, EVR, etc) do no modify the stack from what is shown in the manual.

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Mattx852

Discussion Starter · #11 · Apr 22, 2022

09_Blade said:
Yes. The APE kit comes with exactly what you need. Unless you run an aftermarket clutch (Suter, yoyodyne, EVR, etc) do no modify the stack from what is shown in the manual.

Then I will go with that stack when it’s time. I don’t do a lot of whole shots but I do a ton of canyon riding, some intermediate trackdays. How does this stack change the feel of the clutch?

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09_Blade

· #12 · Apr 22, 2022

The clutch starts out with a slightly wider engagement range than the stock clutch, and has a brief break-in period before it feels normal.

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Sic2JZ

· #13 · 23 d ago

Mattx852 said:
I cleared the expansion hole with some brake cleaner and compressed air and flushed out the system with brand new Motul RBF600. The clutch is grabbing just fine. Even at medium RPM in 6th gear, if I crank on the throttle, the revs stay right where they are supposed to. Probably took some life off the clutch but it feels fine ever since I cleared the expansion hole.

This forum and fix saved me from rebuilding the clutch. Thanks everyone y'all are awesome! Cleaning worked like a champ!

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