Hydraulic Clutch Fluid Issue

Personally, I've never bothered to pre-fill an Oberon slave and wouldn't attempt it. You can fill it in situ just from the master, or if you are very particular you can connect it up to the hose and master but hold the slave up in the air to help with purging it. It really is very simple.

Any tiny bubbles will run back up the pipe overnight and can be purged just by tickling the lever without going for a full stroke. Please: no-one suggest the tie-wrap on the lever overnight because that just dissolves the air into the fluid since there is nowhere for the air to escape. It may give a firm lever action but dissolved air can come back out of solution, just like bubbles in the blood of a diver.

Nick

[Luddite]

Very nice, Ron. Looks good in black.

[Rrawlings]

I’ll be honest and say I didn’t read the instructions or the bits on the Internet I read about filling it. I just chucked the Oberon cylinder on and bled it but used the mityvac much raves about by Luddite and it works wonderfully. The mityvac makes any job with brake or clutch much easier but recommend again following the oracle’s advice, ptfe on threads otherwise the vacuum seal isn’t great and it sucks air in due to the force being used. Before using mityvac though swapped the clutch cylinder on a friends 600ss and used the old fashioned one man bleed kit with equal success

[Ron1000]

Ok so that's it installed. bled so that fluid comes out both the slave bleed nipple and master bleed nipple if opened.....I assume that's the sign of a good system! First time doing a clutch

However (rawlings maybe you could help) the clutch action is very light....like feather light, is that correct?

And it makes a fair thud going into first in the shed.....seemed to be a wee bit better when I adjusted the lever span, first to neutral is a doddle.

So any known issues or problems to look out for or am I in the clear so to speak.

[Mr Gazza]

The Oberon has a greater mechanical advantage than the original slave, as it has a larger piston. So you will feel a lighter pull at the lever. This does however require a longer travel of the lever to produce the same amount of movement of the clutch pushrod than before. so manipulating the handlebar lever adjustment will give you back the rod travel, so long as there is enough adjustment in the lever. Some unsympathetic souls will tell you to bend the lever forwards! I don't recommend that.

[Ron1000]

Cheers gazza, I will not be bending my evotech lever for definite

I had it on setting 3...small hands you see...setting 6 (furthest away) was best for 'thud reduction' . Not so great for my hand span tho, but it's so light now it's not an issue.

[Mr Gazza]

You might even find that another bleed in a couple of days time will improve things? Those slaves are a swine to bleed sometimes and fool you into thinking you have done the job, only to produce air later.

[Luddite]

Originally Posted by Ron1000

However (rawlings maybe you could help) the clutch action is very light....like feather light, is that correct?

And it makes a fair thud going into first in the shed.....seemed to be a wee bit better when I adjusted the lever span, first to neutral is a doddle.

What Mr Gazza said! Because the piston is larger, for any given movement at the lever, you'll get less movement of the clutch pushrod but with less effort when compared to the stock unit. So opening up the lever span is often needed.

My Evo always clunks into first and the fact that you can easily select neutral from first suggests all is well. A further check is to put it on the paddock stand, select first and, with the clutch held in, try to rotate the wheel with your hand. It should turn easily even when cold. You'll feel resistance and it won't spin but you should be able to move it without too much effort.

Of course, if you're running out of lever adjustment, perhaps that's just the excuse you need to get some nice ASV levers!

[Ron1000]

Was Thinking that, I'm letting it all settle down at the moment and will bleed again later. I have a short journey tomorrow (for essentials officer I promise) so I'll check it tomorrow again in the morning then see how it goes.

Oh side note:
(not political) Nicola Sturgeon has announced lock down until end of may for us Scottish chaps. However I'm hearing bojo might ease things a little for you chaps in the south. Jealous is not the word.

[Mr Gazza]

Yeah! Well I taxed the Monster this morning because I had an essential journey today that would go in my panniers, then I found the item cheaper on the net. So I don't have the excuse for the ride.

It was £93 for the year, I'm sure it was only 80 something when it was due at the beginning of April? has it gone up in the last month?

[Ron1000]

Yes definitely dearer. I noticed it also.

[Ron1000]

Okaaaaay. So yes not bled properly. Had it on the stand and the rear wheel was engaged when in first with the clutch in to the extent you couldn’t stop it with a foot or anything else.

So bled it again and it’s much better now. The wheel comes to an almost stop when off the ground in first with the clutch in. The trade off is the clutch is now as heavy or at least only slightly less so than the stock one.

And I’ve now found the classic neutral difficult to find issue.

I’ll re-bleed tomorrow again and see What difference that makes.

[Rrawlings]

I noticed the easier effort and slightly louder clunk but had the advantage of being able to go out for an hour then re bleed it and it seems to be better

[Dukedesmo]

Originally Posted by Ron1000

Okaaaaay. So yes not bled properly. Had it on the stand and the rear wheel was engaged when in first with the clutch in to the extent you couldn’t stop it with a foot or anything else.

So bled it again and it’s much better now. The wheel comes to an almost stop when off the ground in first with the clutch in. The trade off is the clutch is now as heavy or at least only slightly less so than the stock one.

And I’ve now found the classic neutral difficult to find issue.

I’ll re-bleed tomorrow again and see What difference that makes.

Presume your bike is a dry clutch?

If so clutch pack thickness makes a big difference in clutch engagement/disengagement - I find that a slightly thinner pack means I can find neutral at idle much better than the recommended 38mm total pack thickness.

This is something that is more noticeable when you fit Oberon (or similar) slave cylinders for a lighter clutch.

The good news is that as it wears, it gets better...

[Luddite]

Originally Posted by Dukedesmo

Presume your bike is a dry clutch?

It's a wet'un on the Evo, DD.