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Discussion Starter #1
Hey all,

Wondering if anyone else is having this problem, or if you can provide guidance. For awhile now, I was under the impression that my bike was suffering from the elusive "clutch slipping in 5th gear" issue. But today, Jumped all over the bike , running it up through the gears under heavy throttle, and realized that my bike is actually not smoothly shifting into 6th gear, which actually feels like slippage. When shifting into 6th under heavy acceleration, the bike is real slow the change gears until I get off the throttle a little bit, and the 6th gear light is slow to show I'm there.

Any thoughts on where to begin?

Thanks.
 

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I would check the clutch adjustment. You might just be off a little causing the hard shift.
 

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Discussion Starter #3
Thanks, but I am 100% sure I got the clutch adjusted correctly. Triple checked that thing. And it ONLY happens 5th to 6th.
 

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Discussion Starter #5
Yeah, pretty sure that's not the issue. Was doing 85 when I hit 6th gear. If I recall correctly, that's close to 4000 rpm in 5th.
 

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First, the light means nothing. It a calculation made by the ecm that turns it on. X mph at X rpm = 6th gear.

Now as to how the trans shifts. When you shift the trans, the shift drum rotates and moves the forks. The forks slide a dog ring out of or into a gear face. The teeth on the dog ring drop into recesses in the gear face. It's either in or out. In between is chewing your parts, or on a five speed, a false neutral. Even if you move the shifter slow, the detentes on the shift drum will flip the drum over and kick the dog rings into place.

If you feel a slip or a loss of power in under your ars, on a hard high rpm shift, its the clutch. The higher the gear, the more apt it is to slip.

It will feel sort of like an old automatic trans when it shifts and if you watch the tach, you'll see the MPH and RPM close in on each other as the clutch gains purchase.

Once you verify that it is slipping, there are several fixes. Start with trying to adjust it, even if it feels good at the lever.

After verifying that the friction disks are still serviceable, you can put a stronger spring in. The pro being low cost and the con being a harder lever pull. Don't just blow off the harder lever pull and take the cheap fix. A hard clutch lever can be a real PITA in traffic.

You can replace the disk stack with a more durable set of plates. Alto Carbonite PowerPac's seem to be the goto replacements for oem clutches. But it'll set you back about $125. More grip, great friction zone, original lever pull.

If you are making more than 100/100, then you need to step up to a variable pressure plate, or an aftermarket clutch asm. The plates cost a few bucks, but you won't know it's there until you shift at high rpm. It has a little more pull when the weights are spun up. And the aftermarket clutches work well, but cost more than a few bucks.
 

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Discussion Starter #7
Now that answer right there is exactly why I post my questions to this board. I have to say, I struggled with believing that as distinctively as the bike shifts all the rest of the time, why it would be any different in this scenario. Is it fair to assume then that the gray tinted residue on the inside of the derby cover is result of wearing or worn friction plates?

Looks like it's time to pull the clutch and find out for sure.

Thanks for the help Thermodyne.
 

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It's not the tranny slipping it's the clutch slipping. With your mods you should have installed a SE clutch spring, if you did install the SE clutch spring then you may need to readjust the clutch assembly. You may have to pull the clutch pack and clean the plates and check for blueing on the steel plates. I put in SE clutch plates in my bike and the SE plates eliminate the clutch plate damping seat and spring and I don't have any problems with slippage ever since I put in the SE clutch plates.
 

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Discussion Starter #9 (Edited)
That's certainly the way it's looking Ironmark. I guess I won't know for sure until the clutch pack is out and inspected. How significant a difference did the SE clutch make with respect to the clutch lever pull?
 

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A slipping 5th gear is actually a very common indicator of a clutch that's on its way out. Specifically on the twin cam bikes I have worked on, I notice the most notice slippage in fifth.

Change the fluid in the primary to formula +. You stated you've adjusted the clutch properly.

In case you haven't, the procedure is as follows:

1. Put a large amount of slack in the clutch cable via the adjuster.

2. Crack the jam nut free using an 11/16 wrench while using an 7/32 Allen wrench to hold the adjuster. (We're talking about he clutch assembly behind the derby/primary cover at this point).

3. Back the adjuster out a bit using your Allen key.

4. Turn clockwise and adjust the clutch adjuster in until you feel the adjuster touch and make contact. It will be a very soft feeling as you slowly run the adjuster in.

5. Back the adjuster out a half turn.

6. Holding the adjuster in that spot you just backed off to, tighten the jam nut.

7. Take the slack out of the cable at the adjuster leaving only 1/8" of play in the cable.

8. Inspect your cable to ensure it's not binding or damaged. If you have aftermarket bars, whoever did them could have installed your clutch cable improperly and routed it incorrectly causing it to bind. This would cause the clutch not to fully engage thus causing it to slightly slip. I had this issue back when I had my clutch cable replaced by what turned out to be an incompetent mechanic.

If you're stage 3/4, it's definitely time to do something about the clutch.

The SE clutch pack gets rid of both the damper spring and the damper spring seat and the very very narrow clutch plate. It wouldn't be a bad idea to use the SE clutch spring either (I recommend it).

Stage 3/4 you should also be considering a better pressure plate as stated previously.

The good news is....clutch works on these bikes isn't very involved and requires little. An afternoon and a six pack will get the job done.


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Discussion Starter #11
Another question mostly related: I realize that this is subject to riding style, etc, so let me preface the question with the fact that I never slip the clutch, it's pretty much either pulled in or let out, and I always shift to neutral and release when stopped. That stated, what kind of mileage can one expect to get out of a OEM clutch? 26K doesn't seem to be a whole lot to me, but there was a period of time when it was too tight thanks to a mis-adjustment (adjusted while hot).
 

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Another question mostly related: I realize that this is subject to riding style, etc, so let me preface the question with the fact that I never slip the clutch, it's pretty much either pulled in or let out, and I always shift to neutral and release when stopped. That stated, what kind of mileage can one expect to get out of a OEM clutch? 26K doesn't seem to be a whole lot to me, but there was a period of time when it was too tight thanks to a mis-adjustment (adjusted while hot).


Hard to say. Theoretically, a lot. It's a wet clutch so the longevity is significantly longer than that of a dry clutch (assuming adjusted properly, not abused, etc.). Things such as your clutch cable, and even the primary fluid you use can also play a part with significant impact on how long the clutch lasts.

Wet clutches need to be ran with the right fluid. Some clutches are capable or require synthetic fluid, others like the stock clutch should be ran with fluid of a non synthetic makeup.

As for the stock Harley clutch, stick to formula +. I personally have never had an issue with formula plus involving clutch sets and have never had any of the bikes I have worked on come back with clutch issues aside from that of abuse. In my opinion, the stock clutch just doesn't react well with syn fluid in the primary. I've seen bikes start to slip in high gear after using syn oil for a few thousand. Not noticeable at all in lower gears, all properly adjusted. Never had these issues but with syn fluid on the stock clutches. Take that as how you will.....

I also still use Formula + with my SE clutch. Very positive engagement and the clutch stays engaged and locked up with full throttle all the way through fifth and sixth. I can even drag the brakes and still see no slippage.

Having the clutch improperly adjusted like in your instance probably played a part in the wearing of your clutch. Hard to say how significant that part was, but nonetheless the dealer specifies it's procedures in a certain way for specific reasons. As for the clutch, those reasons are to prevent excessive wear and damage to other parts.

In your instance, you unintentionally deviated from that set path of maintenance and are now subsequently paying the price. We've all been there man. Just be happy it wasn't some other knucklehead who caused you all this grief.

Hell, I had some moron route a clutch cable just bad enough to cause it not to fully engage. We're talking just barely. Probably wouldn't have been much of an issue honestly if my bike was stock, but it's not. I had to do the clutch set and reroute the cable, none of which I wanted to do then, or now. I've got the hemmie's pretty bad right now in my early twenties, so the last thing I want to be doing is sitting on some hard roller chair doing a damn clutch! What a drag! (Haha.....pinky right?).

Hey man,
Best of luck to you. Throw the SE clutch in. It's cheaper than the HD kit. If you make a lot of power, do the pressure plate and diaphragm spring while you're there.

-Nick


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The life of the plates is related to the heat they were exposed to. With a wet clutch, the oil is about cooling the plates. And when the plates slip they make heat. And unfortunately, when they slip at high speed, they tend to be slinging the oil away too.

The plates can wear down, as in get thin, as the friction material wears away. This can be checked by measuring the height of the stack. As the stack wears down, the spring has to extend further into the basket to push on them. As the Belleville disc spring reaches out to the stack, it looses tension.

Another thing that can happen is that the disks get hot enough to glaze over, or get shined up. This makes the surface slick and resistant to gaining purchase on the steels.

When you pull off with these scooters, you have to slip the clutch. They are geared too tall to not need some help to get moving. And while that slip-to-start does wear the disks, it's not a lot. Well not a lot as long as you only do it for a few feet. They just don't slip long enough to get hot on a normal pull off.

What burns the disks up is slipping at speed. Were the slippage goes on for miles and miles. By the time you feel it slip, it's been slipping for a long time already.
 

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The life of the plates is related to the heat they were exposed to. With a wet clutch, the oil is about cooling the plates. And when the plates slip they make heat. And unfortunately, when they slip at high speed, they tend to be slinging the oil away too.

The plates can wear down, as in get thin, as the friction material wears away. This can be checked by measuring the height of the stack. As the stack wears down, the spring has to extend further into the basket to push on them. As the Belleville disc spring reaches out to the stack, it looses tension.

Another thing that can happen is that the disks get hot enough to glaze over, or get shined up. This makes the surface slick and resistant to gaining purchase on the steels.

When you pull off with these scooters, you have to slip the clutch. They are geared too tall to not need some help to get moving. And while that slip-to-start does wear the disks, it's not a lot. Well not a lot as long as you only do it for a few feet. They just don't slip long enough to get hot on a normal pull off.

What burns the disks up is slipping at speed. Were the slippage goes on for miles and miles. By the time you feel it slip, it's been slipping for a long time already.


That last paragraph is worth a thousand words. I couldn't agree more, if you feel it it's too late.

Heat kills a lot of things, clutches being one of them OP. If you've serviced and properly adjusted already and still have slippage, it's time to pull the primary cover and tear that clutch down.

-Nick


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Discussion Starter #15
Ordered a digital caliper that gets here tomorrow, and I'm gonna pull the clutch and take a look and some measurements. Thermodyne, you suggested the Carbonite might be a good path for replacement in the likely event I need to go there, and I'm seeing some comments on the SE clutch that lead me away from it. Is the Carbonite plate stack combined with the SE diaphragm a good path, or stay with the stock spring? Any other comments from ya'll?
 

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Ordered a digital caliper that gets here tomorrow, and I'm gonna pull the clutch and take a look and some measurements. Thermodyne, you suggested the Carbonite might be a good path for replacement in the likely event I need to go there, and I'm seeing some comments on the SE clutch that lead me away from it. Is the Carbonite plate stack combined with the SE diaphragm a good path, or stay with the stock spring? Any other comments from ya'll?
Hard to say. Depends on power, load and how you ride. I would strongly recommend that you avoid the aftermarket gorilla springs

The fact that it's slipping says it needs work. If the plates look good, and it has a yellow spring in it, you could try the pink spring. 37807-03

Or you could just replace the plates and see how it does with carbon plates and the oem spring.

If new plates and the pink spring won't hold it, my advice would be to spend the money on a Centrifugal pressure plate.

https://aim-tamachi.com/pages/variable-pressure-clutches-1
 

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Discussion Starter #17 (Edited)
With just Stage 1 (for now at least), I can't imaging the need to push the envelope. And I just put a new Barnett clutch cable on, and the pull is smooth as hell. I like that and would prefer it stay that way, but obviously make the slipping stop.
 

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Slippage is slippage. If you adjusted properly and it's slipping still, it needs to be opened up.

You should be fine with the SE clutch pack. Stiffer spring would be an optional purchase for you. If it were me I would do the spring too. Stage 3/4 do the pressure plate.


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Discussion Starter #19
After removing the outer chain case and pulling the clutch, I'm happy to say that the friction plates are all very much within spec, and the steels are clean and not at all blued. I replaced the stock diaphragm spring with the SE spring, put it all back together and filled it with Formula+, and all is well. Shifts clean and crisp, and just feels tighter all around.

Thanks for the help and guidance.
 

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After removing the outer chain case and pulling the clutch, I'm happy to say that the friction plates are all very much within spec, and the steels are clean and not at all blued. I replaced the stock diaphragm spring with the SE spring, put it all back together and filled it with Formula+, and all is well. Shifts clean and crisp, and just feels tighter all around.



Thanks for the help and guidance.


Glad to hear it. It's amazing what that spring does in terms of slipping.


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