Clutch problem

Here be mechanigeeks. Anything technical that is not a teething problem.
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Herb
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Clutch problem

Post by Herb » Mon Jun 11, 2018 8:26 am

Hi.

My clutch has recently started playing up. Seems fine when you first start the bike, but after a few miles the clutch starts coming further and further back to the bar before it will disengage, eventually not disengaging at all, resulting in drag and difficultly changing gear.

There is no slip I can discern. I am going away on the bike shortly, so I need a quick solution.

What do I need to check? Is this simply a case of bleeding the clutch, or is this likely to be something more severe, perhaps a leak somewhere.

Any advice gratefully received. I need this resolved this week.

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limeyduffa
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Re: Clutch problem

Post by limeyduffa » Mon Jun 11, 2018 10:52 am

Hi Herb. Two things come to mind:

a) Low oil/oil leak/air in clutch hydraulic system

b) Clogged clutch oil jet.

What size clutch oil jet are you running ? 0.3mm, 0.4mm, 0.5mm ?. What engine oil are you using ?. How hot is it in England at the moment ?

Herb
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Re: Clutch problem

Post by Herb » Mon Jun 11, 2018 10:58 am

Hi Limeyduffa,

I was thinking along the same lines as you, air in the system, which I guess could be indicative of a leak?

There is no oil leak visible that I can see, either from the master cylinder or the slave, I will inspect properly tomorrow morning.

The bike is dealer services, so will have whatever the KTM main dealer use. The temp last night on the ride home was about 12 degrees, so not hot at the moment.

I am tempted to order a replacement slave and re-bleed with that, so at least it rules out any problems. Am I right in thinking there are known issues with the standard slave?

Sorry, no idea about clutch oil jet?

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limeyduffa
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Re: Clutch problem

Post by limeyduffa » Mon Jun 11, 2018 1:03 pm

Here you go Herb, it's a long thread, but it's all there (see below). If in doubt, it's a quick check you can do that won't cost you anything. I use a 0.5mm jet. The 0.3mm blocks too easy and when it does it makes the bike feel like I'm doing clutchless shifts. The blocking is temperature and oil viscosity dependent and the jet size is a trade off between crunchy shifting or semi-engaging (dragging) clutch when stationary (worst when engine is cold). 0.5mm with 10W50 oil in 0-30C weather optimal IMO.

viewtopic.php?f=13&t=5431

Herb
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Re: Clutch problem

Post by Herb » Mon Jun 11, 2018 3:16 pm

Thanks. I’ll check it out on Wednesday and report back.

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Re: Clutch problem

Post by Magic Wand » Mon Jun 11, 2018 9:54 pm

Hi 'Herb'!

Me as well recommend you to have a read through the thread that 'limeyduffa' put up the link to.
Read it and yu will learn a lot about the clutch oil jet, Oberon slave cylinder, type of oil to use in the system and more.

/Magic

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Re: Clutch problem

Post by Herb » Tue Jun 12, 2018 6:32 pm

Oil jet was clean. (0.3) but thanks for pointing me in the direction of this. Something to make sure I keep an eye on.

Once apart the problem was pretty obvious, lot of oil leaking from the slave. Oberon part on order, so hopefully I should be back on the road in a few days.

Herb
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Re: Clutch problem

Post by Herb » Fri Jun 15, 2018 8:50 pm

Back on the road, Oberon fitted.

Satisfying job. Reverse bled with a syringe, nice and easy. Even got the syringe free from my vet, which was nice.

After much research, I used LHM+ mineral oil which cost me £6 for 500ml. That's a lot of fluid changes.

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Re: Clutch problem

Post by linehand » Fri Jun 15, 2018 9:22 pm

Nice fix. Funny how Ktm and Ducati can't seem to sort out such a dead simple part like a slave cylinder. Keep an eye on the clutch master cylinder as well, mine got weepy around 30k miles and after reading about issues around the forums I ended up just replacing with another model from magura. No issues since.

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Re: Clutch problem

Post by Herb » Fri Jun 15, 2018 9:29 pm

its because almost every part on a modern vehicle is built to 'just' do the job at the lowest price. The Oberon is a quality part, that probably costs Oberon 20 times as much to procure as the part KTM fit as standard.

Reminds me of the John Glenn quote:

‘I felt exactly how you would feel if you were getting ready to launch and knew you were sitting on top of 2 million parts — all built by the lowest bidder on a government contract.’

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Re: Clutch problem

Post by limeyduffa » Sat Jun 16, 2018 11:04 am

Luckily John Glenn didn't have KTM's bucket tappets in the Saturn V rocket otherwise he would have been rooted ! :lol:

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Re: Clutch problem

Post by Magic Wand » Sat Jun 16, 2018 12:05 pm

Great with the Oberon slave cylinder!
Me as well replaced the original slave to an Oberon, 'some miles' ago - and at the same time I changed the mineral oil to Castrol Front Fork oil 5W.
The engine and the original master slave has been running for more than 57000 km.

/M

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Re: Clutch problem

Post by Herb » Sat Jun 16, 2018 12:13 pm

I have another, seemingly unrelated issue with the wiring to the ignition switch now. I could scream with frustration right now. I'll start another thread, but basically the bike was dead when I move it from the garage. A bit of investigation and it seems that the wire to the side of the ignition barrel must be damaged. If I put the slightest pressure on this wire, everything comes on. Take the pressure off, and electrics go off again.

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