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Discussion Starter · #1 ·
From the word “GO”, my slipper clutch has been making my butt pucker with all its weird idiosyncracies. I think I have found the culprit.

The bearings are too large to fit in the grooves of the lower portion of the hub. It’s not something I noticed until today because during assembly, you hold them in place at the base of the groove with grease.... I couldn’t see the miss fit. But, as you can sorta' see in this pic, they don’t set down in the groove as they go up the ramp. I wedged them in place for the pic.



They fit fine in the grooves of the upper section of the hub.


If you can remember, this is where they ended up the first time they jumped ship.


The thing would work fine for a while and then go into a full blow epileptic seizure. It left me stranded today. That’s when I did some in-depth detective work. I think with the over sized bearing, it would work alright while the grease was plentiful and then bind up once things thinned out a bit.

Also, I don’t understand why it was designed so that it could ramp up so high that the bearings could come out of their respective ramp grooves.

I’ll try to find some bearing that are a pube-hair smaller on Monday.

Anyone have any other theories?
 
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Discussion Starter · #2 ·
Re: Slipper clutch problem solved...? (Mental998)

I do know your clutch tool should be in your hands on the 3rd.
 
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Discussion Starter · #3 ·
Re: Slipper clutch problem solved...? (Phil 998)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Phil 998 »</TD></TR><TR><TD CLASS="quote">I do know your clutch tool should be in your hands on the 3rd.
</TD></TR></TABLE>

Good..... I'll need it to install the new STM slipper I'm going to buy.
 
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Discussion Starter · #4 ·
Re: Slipper clutch problem solved...? (Mental998)

I have installed STM slipper clutches and once the stack height is spot on they work flawlessly.
That thing you have is screwed up since the ramps are of different size. If you get a bearing that fits the lower then it will be too small for the upper.
 
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Discussion Starter · #5 ·
Re: Slipper clutch problem solved...? (Phil 998)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Phil 998 »</TD></TR><TR><TD CLASS="quote">If you get a bearing that fits the lower then it will be too small for the upper.</TD></TR></TABLE>

Could be...
I'll keep dinking with it. I'd hate to end up with an $800.00 paper weight.
 
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Discussion Starter · #6 ·
Re: Slipper clutch problem solved...? (Mental998)

Take a dremel and make the small slots the same size as the others that fit. Wouldn't that solve the problem the easiest way?
 
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Discussion Starter · #8 ·
Re: Slipper clutch problem solved...? (TK)

Yeah... I'll try to do enlarge the ramp grooves.

I will fix this bitch by the end of the day or I will...........



.....buy an STM.


Darin, if I can't get it to work, I'll give it to you to play with. It'll piss you off to no end, but what are friends for anyway?
 
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Discussion Starter · #9 ·
Re: Slipper clutch problem solved...? (Mental998)

I'm sure I could get those ramps massaged in for you. Or just screw it up.
 
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Discussion Starter · #10 ·
Re: Slipper clutch problem solved...? (Mental998)

hey mental, what kind of grease are you using?

hey phil, what stack height do you start with and how do you know if you need to add or subtract to the stack? i still have the stock 748r slipper, i know it's nowhere near the greatest, but i can't afford to plunk $1k for a new yoyodyne one so i'll have to make due.

cheers, kent
 
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Discussion Starter · #11 ·
Re: Slipper clutch problem solved...? (slowpoke)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slowpoke »</TD></TR><TR><TD CLASS="quote">hey mental, what kind of grease are you using?

hey phil, what stack height do you start with and how do you know if you need to add or subtract to the stack? i still have the stock 748r slipper, i know it's nowhere near the greatest, but i can't afford to plunk $1k for a new yoyodyne one so i'll have to make due.

cheers, kent</TD></TR></TABLE>

I start with 36mm.
 
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Discussion Starter · #12 ·
Re: Slipper clutch problem solved...? (section8superbike)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by section8superbike »</TD></TR><TR><TD CLASS="quote">

I start with 36mm.
</TD></TR></TABLE>

Thanks Phil.
I also use 36mm, it can range from 36 to 36.5 normally.
 
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Discussion Starter · #13 ·
Re: Slipper clutch problem solved...? (Phil 998)

I’m just using a heavy...grease. I tried to find some more silicone based grease, but so far have had no luck.

Slipper Clutch Theory 101: The critical measurement is how far off the clutch hub the pressure plate sets, because that determines how far the hub has to ramp up before it will push against the plate and start to slip. That measurement is probably different depending of the type clutch you have.
With my clutch hub setting on the work bench and the plate setting on the hub, I have 34.5mm from the top of the hub base to the back of the plate. That’s the space I have to fill with clutch pack.
I installed the clutch pack ( for the fifth phucking time in less than 24 hours) and I gave myself as close to the 34.5 as I could get: 1mm over. So now, all the POS has to do is lift a lousy 1mm before it should start to slip.

There is no way those bearings should ramp out of their grooves with only 1mm of movement. The grooves are all big enough now. It’s just been greased and... the sun is out, so the thing better work.

I’ve got a big ass hammer.... if know’s what’s good for it.... it...will...work.

 
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Discussion Starter · #14 ·
Re: Slipper clutch problem solved...? (Mental998)

It has been a bit of time since I set up a STM, so this might not be right, maybe someone else who REALLY knows can shed light, but I think I set it up so there is 2mm between the inner hub and the pressure plate when it is set up right. I had to measure the height of the pressure plate onto the hub with no plates and then with plates and do the math, but I'm pretty sure that 2mm figure is something golden. If it is less it won't slip early enough and not act like a slipper and if it's more it will slip with the slightest closing of throttle.
 
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Discussion Starter · #15 ·
Re: Slipper clutch problem solved...? (Phil 998)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Phil 998 »</TD></TR><TR><TD CLASS="quote">If it is less it won't slip early enough and not act like a slipper and if it's more it will slip with the slightest closing of throttle.</TD></TR></TABLE>

Isn't it the other way around.... if the stack is too tall it won't slip, if it's too short it will slip if you look at it cross-eyed. That's what I'm trying to get this one to do... slip real easy and then work back up.
 
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Discussion Starter · #16 ·
Re: Slipper clutch problem solved...? (Mental998)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mental998 »</TD></TR><TR><TD CLASS="quote">

Isn't it the other way around.... if the stack is too tall it won't slip, if it's too short it will slip if you look at it cross-eyed. That's what I'm trying to get this one to do... slip real easy and then work back up.</TD></TR></TABLE>

HUGE brain fart. Yes you are right, if the inner hub is too close to the pressure plate then it will slip at the slightest closing of throttle and if the distance is more than 2mm then it won't slip much at all. DAMN IT, I said it was a long time. Sorry about that.


Modified by Phil 998 at 12:31 PM 2/27/2005


Modified by Phil 998 at 12:32 PM 2/27/2005
 
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Discussion Starter · #17 ·
Re: Slipper clutch problem solved...? (Phil 998)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Phil 998 »</TD></TR><TR><TD CLASS="quote">HUGE brain fart. </TD></TR></TABLE>

Could be age...


I had to add another .5mm to the stack, but things seem alright for now. That puts me right back at a 36mm total. With the bearings now able to roll up and down the ramps freely, maybe things will hold together.

I put away my huge hammer... for now.
 
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Discussion Starter · #18 ·
Re: Slipper clutch problem solved...? (Mental998)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mental998 »</TD></TR><TR><TD CLASS="quote">Could be age...
</TD></TR></TABLE>

Knock on wood I'm not getting senile......is that someone at the door?


The magic number is the 2mm from inner hub to back side of pressure plate, it just turns out that a stack height of 36mm ususally gets it to the 2mm distance.
 
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Discussion Starter · #20 ·
Re: Slipper clutch problem solved...? (Tornado-rider)

The ramps can be widened a hint with a dremel although you cut through the anodizing at that point. My concern would be the damage I have highlighted in the photo. That is not right, what is the deal with that?

 
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