106 replies to this topic

[Dan Williams]

Please do post pics of the "factory" plates.

[hammerski]

Sorry for beeing so slow with the pictures! have to admit I totally forgot.. But here they are! i didn't see an easy way to upload pictures here, so I decided to make a facebook album

I think i made it public, so you dont need facebook to wiev it, but if anyone have problems just PM me!

Martin

[HAM2]

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[Dan Williams]

Thanks for posting. Not quite as "clean" as I was anticipating.

[fkrisztian]

I've found a REALLY good oil which COMPLETELY eliminates clutch drag problems:
http://www.lucasoil....p?product=10281
It's a 0W-5 oil, so it's viscosity is lower than ATF oil's viscosity.
(Lucas Oil) Visocisty 40°C: 11,00 mm²/s
in comparison:
(Red Line ATF Dexron III) Viscosity 40°C: 34 mm²/s
(Putoline Light Gear) Viscosity 40 °C: 36,00 mm²/s
(Putoline GP10) Viscosity 40 °C: 33,50 mm²/s

And we are talking about gear box oils. In a 4T engine, the oil's viscosity helps the oil to remain on the sidewalls of the cylinder. But the gearbox is literaly in an oil shower, so it's not that important to use a high viscosity oil.

[youthy]

Do you think this will work on gas gas renowned for clutch drag? I'm not familiar with beta and sherco clutch systems but know the gas gas is it's own unique ( pain in the ar*e)system

[NZRalphy]

fkrisztian, on 06 December 2011 - 03:11 PM, said:

I've found a REALLY good oil which COMPLETELY eliminates clutch drag problems:
http://www.lucasoil....p?product=10281
It's a 0W-5 oil, so it's viscosity is lower than ATF oil's viscosity.
(Lucas Oil) Visocisty 40°C: 11,00 mm²/s
in comparison:
(Red Line ATF Dexron III) Viscosity 40°C: 34 mm²/s
(Putoline Light Gear) Viscosity 40 °C: 36,00 mm²/s
(Putoline GP10) Viscosity 40 °C: 33,50 mm²/s

And we are talking about gear box oils. In a 4T engine, the oil's viscosity helps the oil to remain on the sidewalls of the cylinder. But the gearbox is literaly in an oil shower, so it's not that important to use a high viscosity oil.

Sorry I dissagree. The Beta clutch plates are a mess from the factory and need to have the clutch fix done. Then put in your good oil.

[fkrisztian]

I would like to share what I found out.
Let's take a Suzuki Gsx-r 1000 clutch. It works perfectly and it's easy to find neutral all the time. Many people use 10w-40 oil in their Gsx-r. Of course it's a 4T engine so the oil lubricates the engine, too. With an installed oil temperature gauge it turns out that in normal conditions the oil's temp is around 200 °F (95 °C). A 10w-40 oil at 200 °F has a viscosity of 14.6 cSt.

A trials bike crankcase oil is not heated up by the engine. Of course by the friction of the gears it still warms up to about 105 °F (40 °C). If we look at an average gear box oil, then we will find that it's viscosity at this temp is 64.3 !!!!!!!! It's a huge difference, it's like spinning the clutch in glue. Of course it's hard to find neutral and the gearbox is not working that smooth. So we are all using ATF and or Putoline Light Gear oil. And it's working somehow, because ATF Dexron III has a viscosity of 34 cSt.

But we can still make it better. We need an oil with 14.6 viscosity at 105 °F (40 °C) NOT 34. This means that we need a 0W-5 oil (or 0W-2 if it's possible). It's not that easy to find this kind of oil, because it's used only for racing, but it can be ordered from the internet.
For example:
http://www.redlineoi...x?pid=10&pcid=1
(Vis: 11)

If you really don't want to order from the internet, then any 5WT (or 2WT) fork oil has also the wanted viscosity, like Putoline Fork Oil Light (http://www.putoline....fork-oil-light/) (Vis: 15) but this is not really a good idea, because we don't know what additives was added, but it helps to understand the idea behind this. You will see that those who ride 4T trials bikes have less clutch drag problems. This confirms my theory.

P.S.: This oil seems also a great option:
http://www.lucasoil....p?product=10539
(Vis: around 10 cst I think)

Edited by fkrisztian, 16 January 2012 - 12:32 PM.

[Dan Williams]

I think the fact that everyone who's done the clutch mod has been really happy with the result confirms my theory.

I'm glad you're putting in the effort to understand the finer points of oil but the mechanicals of the clutch plates as shipped from the factory make the oil argument moot as they simply can't work the way they are designed to work. A clutch designed to provide a controlled friction characteristic fiber to steel is just not going to behave with a significant glue to steel contact area. The same can be said of the tabs which are sliding bearings. Glue and rough surface finish are just not a good bearing.

[chewy]

new bike same problem so back to basics and dans clutch fix; Ralph say's it all " the plates are a mess from new". As I had time for a change had a good look at the whole thing and how it "works" or not as is invariably the case.
Basics such as amount of lift are not specified mine had 1.1 mm and no apparant hydraulic problems asked Beta Uk who avoided an answer so had to assume that was as good as it gets.
Plates Jamming.
A) Driven plates on the hub; part of Dans fix is to break sharp edges to avoid them "digging in" to the hub
Driver plates another of Dans remedies... tags bruise the basket and subsequently wont slide or dig in as above so smooth basket and break sharp edges on plates.
Both these parts of Dans Fix are the most effective thing to help the plates seperate when you pull the lever.
We then have to check the plates for flatness and surface condition.
Flatness / separation;.... If you have 7? driver and 5 driven plates and each one is 0.1mm out of flat with 1.1mm of lift you have a problem.
Surface finish of driven or steel plates ;... my problem with this years bike was plates sticking together. It looks like factory have made some effort to improve the clutch action, with oil weep or feed holes in the hub drilled to correspond with each driven plate..so they want oil to get into this area...it seems to me that once the oil is in it has nowhere else to go when the plates are together or in mesh. shot or bead blasting the friction area breaks up the surface and sorts the problem for a few weeks but once they're run into each other you're back to square one.
I did notice that the bruising on the basket on mine was eccentric...further investigation revealed that the hub & the basket were not concentric; fortunatly I was able to reposition the hub on assembly to ameliorate this... The clutch works well at the moment running with ATF... when it has run itself in I have some 0w 20 synthetic oil to try along with lighter springs to get a bit more sensitivity into the action. but am riding this weekends event with all std parts and the ATF.
It really is a painfull process to have to go through, but Dans observations put so eloquently by Ralph are true , all we can do is fettle as best we can to m try to make a silk purse out of a sows ear. I have another little project going on (see my facebook if you know me and are interested) but that will be subject to a lot of testing. As you can see there are a lot of variables in this assembly.

[0007]

Well I did the mod to my 07 Rev, I have not been on a ride yet but I let it sit 2 weeks and for the first time when I put the bike in gear cold the bike did not stall, in the past it would stall at least once, maybe twice
My original issue was that the engagement of the clutch was over a very short stroke and was difficult to modulate, it was like 7mm of lever travel, maybe a bit more
I can't see how this mod will change that but it seems to be different but I have not got the bike up to full operating temp, oddly enough it seems to have a slight amount of drag now which I never had before but it still starts in gear so it's not that bad
More to follow

[rallymadsam]

How tight do you generally do the springs? Is there a recommended torque setting or anything?

[chewy]

I just do mine up hand tight..feels like the bolt is bottoming out..... Has anybody else measured the amount of lift of the pressure plate for a full pull of the lever? Simple if you have a DTI (clock) I get 1.1 mm of lift and can't verify if this elementry thing to establish is good bad or indifferent.
Been runnimg for c.10 hours now with a 0-20w synthetic oil (total quartz). I can feel clutch disengaging better when revving the motor...as if oil is throwing out from centre of hub (as revs pick up) through the "weep" holes and between the plates... so am thinking more weep holes as in Martin H .'s facebook pics.. I did note that my as from new (2012) has radially drilled holes which line up with steel or driven plates; from memory one hole per plate c.2.5 mm dia. I had some driven plates lasered with oil grooves (bit like a brake disc) but the finish where they engage the hub was no better /maybe worse than std. so I bit the bullet made a milling jig and using a 2mm dia end mill remachined the whole thing with as good a finish as I could get (high revs carbide slow feed... any machining lay or marks, less than a few microns at least align perpendicular with the direction of slide on the hub)... put rads (0.08mm) on all sharp corners.. & lapped them flat this made a big difference as does a good beadblasting incidentally but clearly not practical for production method. In search of perfection now I'm going to try a std 15/30 oil (as is in my wifes..same bike) which works well from new with no mods. After that I may try drilling the hub to feed more oil twixt the plates but I need to buy (what a trials guy spending money!!!) new locking tab washer ..don't like to unfit...refit more than once. Went to classic bike trial last weekend and rode a few of them SWM Yam Fantic all c 25/30 years old and had better clutch than any Evo I've ridden..thats progress I suppose.

Edited by chewy, 28 April 2012 - 02:20 PM.

[hugh_b]

torque setting for the springs is 10nm as are the 4 bolts for the clutch cover.

Hugh

[rallymadsam]

Thanks for the above chaps, haven't got a torque wrench that goes that low, so did the spring bolts up with a socket by hand, and felt them bottom out, so that'll have to do.