Hmmmm.

I'm tempted to try new clutch plates but would rather buy new clutch plates because I know it needs new clutch plates rather than just guessing and spending money.

The clutch plates look like any others I've seen before and were flat and in good condition.

When it first started doing it I had been riding all day, my test today I rode for perhaps 10 minutes and it was ok, then dragging, ok, then dragging. But the dragging is so bad as described before that pulling the front brake will push the front wheel or stall the engine!

 

Looks like you need to be sure that the clutch lever piston is free to fully return to its start position, as it opens the reservoir port there.  If you have got the clutch cover off, you could check that the pressure plate is moving out whilst you pull the clutch lever.  Not too sure of the actual movement, but it should be near 5mm or so.

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Thanks for the suggestions so far.

I'm fairly sure the momevment is correct but haven't physically measured it, I've been moving the clutch lever with the clutch cover off and looks good.

I don't mind buying new clutch plates, they are a wearable item after all, but in my mind, as the plates wear you get clutch slip, not clutch drag.

I don't want to chuck £70 ( or whatever they are ) at some new plates if that isn't going to solve the problem.

I'm out on the Enduro bike in the morning but in the afternoon I might have some free time.

I think my next steps are to physically measure the clutch movement with a vernier or dial gauge, I've also found that Beta USA clutch set up article so I'm going to check which way my 'top hats' are facing, then ride as much as can up and down the street and doing figure of eights in the drive and get some proper heat into everything and see what happens.

Then I'm going to have the clutch cover off again while everything is hot and re-measure everything.

Hi Whitevancam,

If you'd read this entire thread (it would take a while :-)) you might have seen my experiences. My clutch was just like yours; literally pushing a locked front wheel forward! I did the whole de-glue and tab rounding thing and found very little to zero difference but what I did in the end (which worked) was to replace the two thicker plates for standard thickness ones, filled up with Putoline nano-trans and Bob was my Uncle. The difference was night and day, it's perfect now and I can even select neutral with the engine running as easily as one would expect to be able to. I don't really know why replacing the two thicker plates had such an effect but it did but I also absolutely swear by the Nano-trans oil now too. Hope this helps mate

About time Beta addressed this problem,diaphragm clutch like the other brands?

4 hours ago, harryharls said:

Hi Whitevancam,

If you'd read this entire thread (it would take a while :-)) you might have seen my experiences. My clutch was just like yours; literally pushing a locked front wheel forward! I did the whole de-glue and tab rounding thing and found very little to zero difference but what I did in the end (which worked) was to replace the two thicker plates for standard thickness ones, filled up with Putoline nano-trans and Bob was my Uncle. The difference was night and day, it's perfect now and I can even select neutral with the engine running as easily as one would expect to be able to. I don't really know why replacing the two thicker plates had such an effect but it did but I also absolutely swear by the Nano-trans oil now too. Hope this helps mate

Interesting. I'm wondering if there is a different friction material in the thicker plates, which might be the cause of sticking. As my 4T has all thick plates (I assume this is correct) that might be an explanation of my problems.

I think I remember reading somewhere that "thin" plates are 2.7mm and "thick" ones are 3.0mm. Can anyone confirm? Certainly my plates measure 3.0mm.

No time to do a proper investigation yet but I have just measured the travel of the pressure plate.

It is moving about 0.6mm from fully engaged to fully disengaged, if I divide that by 12 friction surfaces ( 6 plates that is 0.05mm per friction surface of movement ) if I had been asked to guess I would have said that the clutch moves a couple of mm but having never measured it before I don't really know what to expect.

I've got to do some parenting this afternoon so have left the clutch lever cable tied back to the bars to see if it creeps back down whilst I am out, this might give me an indication of whether the master cylinder is passing.

We'll see this evening!

Ps. Can you buy just individual 'thin' plates or would I have to buy a complete set??

Yes you can buy them individually, I got mine from Beta UK in Skipton

Thanks guys, I think I have a diagnosis.

I got back this evening to find the cable tie still in place but the clutch fully engaged, i.e. the measurement was the same as with the lever released.

Snipped the cable tie and pulled the lever a few times and the pressure plate movement was the same as before, about 0.6mm.

I then pulled and held the clutch lever and 'rattled' the top friction plate up and down with my finger, after about 20-30 seconds I couldn't rattle it anymore, the gap had gone.

So I think I have knackered master cylinder or master cylinder seal.

I think I can eliminate the slave cylinder as the fluid level in the master cylinder has remained constant throughout all this. If the slave seal was knackered I am assuming that the level would drop as the fluid pushes past the seal and into the gearbox and the level would drop.

I'm going to try to order a new master cylinder or repair kit tomorrow and will report back!

Thanks again for all your help so far.

It doesn't matter where the system looses fluid from it still replenishes from the reservoir. Definitely sounds like a leaky cylinder. Good job of isolating it though the travel of your throwout plate might be smaller than I'd expect.

Hi Guys, just taken the cover off a 2008 250 Rev3, and it has plain washers.  As far as my digital callipers could see, the movement was just about 1.2mm.   It could be that you would get less movement if there are small air bubbles in the hydraulic line.   However there may be several different types of slave and master cylinder combinations, to give different amounts of movements.

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On ‎19‎/‎11‎/‎2017 at 11:35 PM, dan williams said:

It doesn't matter where the system looses fluid from it still replenishes from the reservoir. Definitely sounds like a leaky cylinder. Good job of isolating it though the travel of your throwout plate might be smaller than I'd expect.

Thanks Dan.

That is what I have assumed, if fluid is passing the Slave Cylinder seals it will go into the gearbox, fluid in the system would then be replenished from the reservoir at the Master Cylinder as it is self adjusting and then the level in the reservoir would drop.

If the seals in the Master Cylinder were passing then the fluid would just end up back in the Master Cylinder and the level would stay the same.

As the fluid level in the Master Cylinder reservoir hasn't changed during any of this investigation I'm hoping it is the Master Cylinder seal that is passing as that is what I have now ordered!

I'm still a bit weirded out by the .6 mm throw. Something is still not making sense.

 

addendum: Looking back through this thread it looks like ~1.2mm is nominal travel of clutch actuation.

Edited November 22, 20178 yr by dan williams

This is a bit like doing Heart Surgery by Telepathy....

There is one thing we don't know...  How far does your clutch lever move..?    I measured the ball-end moves 90-100mm from fully out to the handlebars.   There are two adjusting screws that set the start position, and the free-play, which may need adjusting.

I acquired a 2017 Evo 250 And noticed a clutch that would not come “unstuck”. I ran through the fix in about 3.5 hours.  Additionally I installed a Clake One clutch (m/c). 

Wow. What a sweet change in all respects