FMF C.E.B. clutch


19 replies to this topic
  • ncmountainman

Posted July 31, 2004 - 04:36 PM

#1

is anyone familiar with the FMF controlled engine brake clutch? it looks to me it would work like a z-start but better. it seems to be used alot in pro-mx,wonder how it would work in the woods?

  • ddialogue

Posted July 31, 2004 - 05:10 PM

#2

Got a link or a part number? I can't find anything on there site.

**Found it under the info section**

$999?!! HOLY $#@%!!! :thumbsup:

  • mtrablue

Posted July 31, 2004 - 05:46 PM

#3

is that one of the "slipper" type clutches? sounds like the motard set up. when you get off the gas the engine braking doesn't skid the back tire or try to throw you over the bars.

  • tool

Posted August 01, 2004 - 02:25 PM

#4

its not a z-start and doesnt work like one.
fmf c.e.b. - slipper clutch, slips to eliminate engine braking. works like a stock clutch from a dead stop.
z start - auto clutch, slips at low rpm for automatic clutch engagement. the lever is optional.
ive heard the z start can work like a slipper clutch, but i dont understand how. :thumbsup:

  • ncmountainman

Posted August 01, 2004 - 04:17 PM

#5

gotcha,saw it in a advertisement and it didnt really say how it worked i thought it was another form of z-start but as usual i thought wrong! :devil: thanx for fillin me in. :thumbsup:

  • ncmountainman

Posted August 06, 2004 - 08:17 AM

#6

after some more research i find that it is made by STM an italian company and is available for the yz/wr 450 ,so i called an fmf guy and asked him what its all about and he tells me that it is very simaler to the rekluse in fact it sounds like the same thing to me. it will come to a complete stop in gear and not stall,you can lock up the rear wheel while riding and it will not stall,when you come out of a corner it automatically slips until its past its set rpm which is adjustable,and best of all you still retain full use of the clutch. dirt rider had some pics of them this month and it looks as if its way better quality than the rekluse! a little pricey at a grand but ya get what ya pay for looks like. he said the same clutch has been used for years in mx with no reliability issues. :devil: :thumbsup:

  • tool

Posted August 06, 2004 - 02:10 PM

#7

thats interesting, nc. i was going off a not-too recent issue of MXA, i think. they said it was a evoluzion(?) clutch or something, made in italy. so maybe the clutch you talking about is a next generation type, or maybe i misunderstood the article. :thumbsup: MXA had a few problems with thier clutch too.
did they say it also eliminates engine braking?
its been my experience that automatic clutch engagement, when used for out-of-the-corner MX type situations, is imprecise and slushy since the "set rpm" has to be very high. it soaks up the snap, exludes you from lugging the engine and causes major heat build up.
a grand? :devil: complete rekluse clutch - 500 bones. :awww:

  • ncmountainman

Posted August 06, 2004 - 05:19 PM

#8

ya not real sure what the rpm range is but he definatly said it was adjustable i mentioned on a hill climb if you set your idle much higher(say 2000rpm) than your stall speed(which is say 1000 rpm?) and then set the clutch to between idle and just above stall(say around 1500 rpm) if it would eliminate the stall but yet still act as a normal clutch if pulled revved and dumped and he agreed that it would .now i know these are trained yes men but i consulted 2 diferrent reps and they both said about the same and seemed knowledgable and yes it reduces engine braking to an extent but not all together so they say! :thumbsup: they said team yamaha mx boys use them. i'd really like to see one in action before layin down that much money or at least talk to someone with one i'll have to call fmf back and see if there are any demonstrations set up for some races. from what i'm gathering it would be hard or impossible to set up the rekluse in the above fashion?

  • ncmountainman

Posted August 07, 2004 - 03:51 AM

#9

o.k. looked it up again and yes it is the evoluzione and yes it is a new generation.it has what they call the new ev 125 spring and new ev secondary spring that they call "completely adjustable" still don't really know if it does what fmf says i'm gonna contact stm(oughta be interesting their websites in italian!)anda seea what they hava to say :thumbsup:

  • tool

Posted August 07, 2004 - 11:13 PM

#10

ya not real sure what the rpm range is but he definatly said it was adjustable i mentioned on a hill climb if you set your idle much higher(say 2000rpm) than your stall speed(which is say 1000 rpm?) and then set the clutch to between idle and just above stall(say around 1500 rpm) if it would eliminate the stall but yet still act as a normal clutch if pulled revved and dumped and he agreed that it would


thats a complicated question. first, for a z start, the stall speed would have to be at around 3000 rpm to get full engagement by 4500 rpm. if the stall speed is very low the bike will creep when stopped in gear, or you may kill the engine with braking. a high idle would make the dragging worse.
also with a z start, you set the stall speed and pick an engagement rate (light or heavy spring), then your done. there no "setting the clutch" after you set the stall speed. that may be different with the evoluzione.
basically the evoluzione and z start sound the same to me, except the evoluzione wants to eliminate some engine braking by using a whole new clutch design.
these clutches make it seem like you can do the impossible (as far as setup goes), but they are limited to certain factors - since they are centrifigal. i have loved it, hated it, now i love it again... all because of setup.
if you really hate engine braking, then the evoluzione would be the way to go. otherwise i would seriously consider a rekluse. :thumbsup:

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  • tool

Posted August 07, 2004 - 11:13 PM

#11

i double posted. :thumbsup:

  • ncmountainman

Posted August 08, 2004 - 01:55 PM

#12

well i would expect it to drag or stall i'm basically wanting to use the clutch as in normal operation, but keep a buffer zone between idle and stall to prevent stall in a situation where i can't grab the clutch in time. in other words the only time i wanna hear from the rekluse is when the bike is about to stall,i really don't want the auto clutch feel just stall protection. is this at all possible? :thumbsup:

  • tool

Posted August 08, 2004 - 09:34 PM

#13

that is absolutly possible, in fact thats the exact way my rekluse is setup. i like to lug the engine so my stall speed is very low, about as low as possible. the clutch only slips when im really low on rpms, this eliminates that zone where the bike wont pull. my bike resembles a manual clutch bike, but i dont have to pull the lever in when i brake, stop or shift. :thumbsup: my bike never, ever stalls even with a yz flywheel.
there is also no clutch pull anymore, as in one finger is more than you'll ever need to pull in the lever. i only use the lever when taking off or brake sliding, and to find nuetral. this clutch is a luxury item, i will never have a bike without a z start. :devil:

  • ncmountainman

Posted August 09, 2004 - 05:55 AM

#14

is there a special setup for this i've heard you need some more ball bearings or special parts to get the stall speed that low? and i would want it lower than yours so that i would have to use the clutch to stop,can it be set that low? you've almost got me sold! :thumbsup:

  • youngwerth

Posted August 09, 2004 - 07:36 AM

#15

I wish I could respond more inteligently to the differences between the STM/FMF CEB clutch vs the z-Start but I have not had the opportunity to ride with one. I understand the principle of the slipper clutch, using rotational load to increase (or decrease, depending on how you design the thing) the amount of spring pressure into the clutch pack. You end up having a tuneable amount of engine braking.

WRT the z-Start setup as an anti-stall device/minimal clutch slip. This can be done. Running 5 Tungsten Carbide balls (25 steel/5 TC balls) in a YZ/WR 450 with the light external adjuster spring will give a very abrupt engagement, almost no slip at all. I ran this setup a couple of weeks ago on my YZ450 and it worked pretty well with the tall stock gearing of the YZ450 on tight trails.

Personally I prefer just dropping to a 13T countershaft and running all steel balls in the YZ450 for the tight trails. A little bit of slip actually works good, especially in the rocks.

Tungsten Carbide balls are available from us, they're $5 each.

I wish I could comment some on the differences between the STM and the z-Start but I have not been able to ride with the STM and would likely only spread disinformation. You might want to check the Supermoto forum for more info.

  • tool

Posted August 11, 2004 - 07:55 PM

#16

WRT the z-Start setup as an anti-stall device/minimal clutch slip. This can be done. Running 5 Tungsten Carbide balls (25 steel/5 TC balls) in a YZ/WR 450 with the light external adjuster spring will give a very abrupt engagement, almost no slip at all.


i knew al would chime in. :thumbsup: nc, this is the setup that im using. im running 5 tungsten carbide balls... it does lower the stall speed enough for me. basically you dont want to have to use the lever to stop, or you'll stall the engine during sudden braking. you want the engagement just above idle, but not so low that the auto part is uneffective.

i get serious chatter with mine, but al has told me this is a pre-04 problem. my off road gearing (15/47) also makes the chatter alot worse, but thats with my YZ tranny. the clutch actually compensates very well for my setup, but im always trying to eliminate as much slip as possible while allowing the auto-engagement to work without too much drag. my bike doesnt creep, but does drag a bit. with the lever, its never a problem.

  • ncmountainman

Posted August 12, 2004 - 04:57 PM

#17

ok starting to get it now(i'm kinda thick headed)so tool you run 5 t/c and 25 steel w/soft spring and it engages just above idle so say i want it right at idle or just below(i know i'd have to use the clutch lever more)what would have to happen, 6 t/c balls or is there enough adjustability in the external adjuster? and am i correct in assuming that more or less t/c balls is how you rough in the stall speed and then fine tune it with the adjuster. al explained alot to me on the tele (very nice guy thanx al) he said you could run up to 8 t/c balls with the heavy spring and get somewhere close to what i'm looking for,have you tried anything like that? :thumbsup:

  • tool

Posted August 12, 2004 - 05:55 PM

#18

i have tried tons of setups, but ive only use 5 carbide balls. basically i see it like this: you try the clutch with all steel balls and the stall speed as low as it goes, then you try the carbide balls if you want a lower stall speed. you will want at least 5 of them.
now with these heavier balls, i was under the impression you could only use multiples of 30, as in 3,5,6, or 10 balls. since the clutch has 30 balls its important to balance the wieght. i cant figure why al told you that you could use 8 balls. :thumbsup:
it seems to me that the heavier spring counteracts the carbide balls. the more carbide balls you use, the lower the stall speed. the more spring tension you use, the higher the stall speed. you want 5 or more carbide balls and very little tension on the light spring. the heavy spring is useless to me (and you).
if your stall speed is at idle, you will kill the engine. to keep from stalling, the clutch has to release before it drops to idle. my setup works flawlessly :devil:

  • ncmountainman

Posted August 13, 2004 - 04:22 AM

#19

maybe he did say 10 (brain fart!) well it sounds like there is enough room for experimentation the only issue i'm trying to solve is stalling i don't mind using the clutch lever,have for 30 years probably would grab it anyway! if i can get it to slip between idle and stall ,which it sounds like i can(that was the original question)it sounds like i'm gonna start saving up! thanx for being so patient with me i just like to fully understand what i'm gettin into! will let you know what happens when i get one :thumbsup:

  • youngwerth

Posted August 13, 2004 - 04:28 AM

#20

I hope I didn't tell you to use 8, only multiple's of 30...

TC balls "steepen" the engagement curve. It takes more spring force (pre-load) to get the same stall speed but then the clutch creates more force at low engine speeds with the TC balls. The transition from not engaged to slip to fully locked up becomes very short with more TC balls.

Some bikes can take more TC balls than others. The YZF has a reasonably tall primary ratio (clutch spins faster, more centrifugal force for any given engine speed) and lots of clutch surface area (more friction). A few TC balls can make a big difference. A Husaberg or a Husky needs 15 TC balls stock to get the same kind of hookup a Yamaha gets with all steel. This is due to a slower primary ratio and also due to a fairly high rate return spring in the clutch slave cylinder. High rate springs are also kind of a bad thing for a centrifugal clutch to overcome (lots of additional force builds against the clutch as it moves from .035" off the clutch pack into the clutch pack).

Hope this info helps...




 
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