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G'Day, Ktm 400 Exc 2001 model.
ok the story goes. last ride lost the clutch over a 30min period to nothing. checked it out and only looked like it was going to be simple, the slave cylinder had rubbed away on its housing and scored it up pretty bad causing the seal to fail. tried a larger o ring to no avail. so ended up getting my hands on a cheap 2006 one. which i had check with ktm and was same part number. only my old one was a superseded model. the new model comes with a cir clip on the reverse side to stop the slave cylinder coming completely out of its housing no big deal. (so i thought and still think???y/n) after back bleeding the system everything was going fine. fired it up to take it for a run and WOW:eek:the clutch has gone completely soft nothing there at all??? shocked at this we bleed the system again and again every way possible to make sure no sneaky bubbles were in our way. again on start up the clutch goes soft! the master cylinder is under 12months old the slave cylinder has just been replaced and working fine the whole system has no leaks or deffects anywhere and feels great ready to ride untill you turn the bike on. after stuffing around with the clutch side of things for days trying every little thing could find on the net remotely close to this problem including checking crank exhaust emissions an't blocked. oil lines and holes still flowing and an't obstructed. well all the ones we could test and try anyways. clutch disk not warpped or bent. and just this arvo we found with the clutch case still off if someone pulls the clutch in and another puts pressure on the pressure piece connected to the push rod the clutch goes soft? depending on how much you push on it depends on how quick it goes soft. and then you just pump the clutch and it starts to come back again. so when the engine is on the engine pressure is pushing on the piece and giving you the soft clutch? the clutch plates move normally along with the pressure plate everything seems normal except around the rod, pressure piece bolt thing and the pressure plate bearing. when we first opened it up the pressure piece was stuck that firm in the pressure plate and bearing we had to use alot of effort to free it up and pop it out? now how tight does the pressure piece have to be inside that bearing as it still has to be able to move but not get stuck? so we shimmed it a bit to a snug fit but so it still could move. but still the same problem continues???? any advice or help would be appreciated guys

oh and a side note was only 5 hours ride time ago the stator had snapped off and had been eating into the flywheel which left alot of metal shavings everywhere but flushed the system 3 times till it was pure. incase this could contributed somehow?

Cheers,

AussieMick :D
 

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AussieMick, welcome.

I will pose your questions to some one with more expertise
in clutch issue than I have.

Will put their reply here soon.
 

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Reply from DJH

Don't ask me what he means, but hre is a reply from DJH (David):

"Standard problem on bike of that era, history;
2000 model had a clutch that spun on a bronze bushing (needed lots of oil) so the routed oil pressure passage into the cavity between the slave and the left side mainshaft bearing so oil would flow thru the main shaft and into the clutch. The oil pressure build up at revs simply pushed the slave cylinder back in so all the fluid in the system flows backwards to the master cylinder, then when you pull the clutch the lever is floppy.
2001 they changed the clutch to a needle bearing which does not need the oil but did they change the oil system, uh not until 2003. Welcome to how KTM deals with problems.
Good news is we have a fix, un-bolt the slave and set it aside, looking in you will see an orange plastic ring, that is the seal of a sealed one side bearing. All we need to do, I use a ice pic, just peal back an edge of that seal, go in with needle nose pliers and rip it out. Now the oil flows into the trans, no pressure build up, clutch works like its supposed to. Done many of 'em"
 

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Discussion Starter #5
Now that sounds promising! ! ! ! my poor mechanics got no hair left after this job!
Bajadog "thanks heaps" for chasing that reply up for me :D
and let David know much appreciated for his knowledge from his ktm mainframe LOL "who the hell knows something like that" :p
will see how it goes tomorrow and keep yous posted.
THANKS AGAIN.


Aussiemick.:)

 

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Discussion Starter #6
Thanks Sooooooo Much For The Help! :D behind the bearing apparently was alot of those metal shavings from the flywheel trouble trapped. also replaced the pressure plate bearing and its all sorted! much appreciated can't thank yous enuff :)

Aussiemick...


(Ps: hope this thread saves someone else alot of pain and frustration)
 

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Is this something I should do to my 05 EXC 400? I have it apart right now replacing the o-ring. Mine keeps losing pressure as well.
 

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Actually I already put it back together and didn't look to see. I had a hard time bleeding it but it looks like it is going to hold. We'll see after I get the valves checked and the rest of it put back together.
 

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KTM 400 exc 2005

I'm having an issue with the clutch in that it's lost all pressure so I bled the system pushing the mineral oil up from the bottom. That worked for about one day then it was back to nothing. I've read something about there being a seal so you can't see the bearings inside the engine but I can see them clearly with no seal or remnants of a seal in sight. All that was in the slave cylinder was the pressure plate with a ball in it and an o-ring around it and a spring behind it. Is the only thing I should replace is the o-ring, or should look for a seal for the bearings. If whatever I should look for can someone direct me to the right sizes and possibly a place to buy.
 

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Dirt Wizard
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There's no seal, only the oring around the outside of the little piston that moves inside the slave. You should just be able to buy that oring from a hydraulic shop. I would just take both bits with you to a hydraulic or bearing shop and show them which oring you need.
 

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Dirt Wizard
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I didn't read back in the post sorry, There talking about the sheild in the ball bearing, If you take the slave off and you look in to the engine you should see a single row ball bearing. If you cant see the cage of the bearing chances are the bearing still has its sheild (seal) in it. If it doesn't look like the picture below, you will need to pluck the sheild out. A scribe or very small screwdriver will do it, don't jam the scribe in, you will damaged the bearing, just push it in lightly near the inner race of the bearing and pluck the seal out.
 

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So I ended up buying a new slave cylinder and that solved the leakage issue, I could've probably just got the o-ring, but my dad bought the whole unit anyways and sent it over. I wasn't able to bleed the clutch without removing the master cylinder piston and allowing the mineral oil to flow through there. I tried pushing the fluid through with the clutch lever pulled in and out. Neither worked. When I took it all apart then liquid started flowing and I simply reassembled without too much fluid escaping through the top and it works fine. It's been about 5 days since I bled for the last time and replaced the slave cylinder and I haven't had an issue.

I am still wondering about the idle. It seems to have a lot of play through the time I have the bike on. Early on it seems to want to keep dying and by the time it warms up It idles a couple hundred rpms above where it should be. I'll let the clutch grab and it will lower the idle back to nearly dying then if I give it gas it will resume idling high, I'm not really sure what to try and diagnose with this problem. I think it has to do with the float, but also something to do with the clutch plates always grabbing and giving me a false sense of where the rpms actually are.
 

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Dirt Wizard
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Sounds like your idle circuit is lean or you have a vac leak somewhere.
Where is your idle mixture screw set at?
 

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I originally set my mixture screw at 2.25 as I had read from many people with my bike, I just changed it to 2.5 and it seems to have had a great effect on the performance of my bike. I could still have some vacuum leak and something else may not be right, but moving it to 2.5 seems to have fixed most of my issues as of now. I can't say too much because I've only ridden my bike twice since I've moved to 2.5, but it feels much better and the idle is much more controlled and has less variation.

I am also having chain slap when I jump something or when I press hard on the shock. Basically whenever the rear shock compresses I hear my chain hitting some other piece. I'm not sure if it's because the chain is too tight, the chain or front sprocket is worn, or what. Could it be that my chain guard that wraps around the front of my swing arm is just worn through and it's actually just hitting the metal? I've read that KTMs of this year range just have chain slap and that's just part of owning the bike. My countershaft seal needs to be replaced I'm pretty sure because they's gook all around the front sprocket and next to the slave cylinder. I don't think that'd have anything to do with the noise, but I'm just pointing that out

The pictures might or might not help
 

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Dirt Wizard
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You may need to jump up a size on your idle jet if it needs more than 2-1/2 turns, the chain does look a bit loose, check and make sure your top chain guide roller is ok and not buggered, its located on the frame above the chain and around about where your left ankle would be. I have also come across people putting to long of bolt in where the subframe bolts to the frame and the chain can slap the bolt. (Similar location)
As for the final drive seal, it could be just an excessive build up of chain lube or it could be the seal, if its not dripping on the ground or dripping while your running, I wouldn't worry about it.
 

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This bike being a 2005, I don't know for sure, but I feel its used the same idle jet thus far and its the right one. I tried adjusting between 2.25 and 2.5 and had varying levels of success but I feel it somehow comes back to the original state. I could just not have the adjustment right, a vacuum leak, the wrong idle jet, or whatever. The bike warms up fine then when I turn the choke off it goes to a really low idle and when I lift my feet of the ground the bike likes to roll slightly forward. I just bled the clutch and put a new slave cylinder in, but the clutch still seems to be grabbing more than I'd like or at least it seems to

I don't believe my bike has a top chain guide roller. I've looked for it on my bike as a replacement and I can't seem to find it on my bike, bikes in pictures, or in replacement catalogs. I think the chain slap is a result of there being too much slack, but I'm not 100% sure. I should probably replace the chain guide near the front sprocket anyways. The chain can reach the sub-frame bolt and it is worn heavily and it's a new bolt because I had to replace it to put the pro moto billet kickstand on there. Would tightening the chain solve that?

I guess I can just pass by the counter shaft drive seal for now.

I've read some and I think it could be warped clutch plates that's pulling the idle down to really low levels.
 

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Dirt Wizard
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I think with full suspension travel you will still hit the bolt regardless of whether the chain is tight, the bolt shouldn't protrude out far enough for the chain to contact it, it needs to be flush or close to flush with the back of the nut thats in the hex recess of the frame, you may need to buy a shorter bolt.
I will attach a diagram of the 05 400 frame, the chain guide roller is number (34)
You could have bad clutch grab, the bike shouldn't creep when in gear, do you have nice full resistance in the clutch lever?
(Did you check to see if the bearing behind the slave was open and didn't have the seal in?)
See how you go.
 

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Thank you for your cordial and quick responses, they have been great help to me in trying to figure this all out.

I couldn't find a place where the roller would bolt on, trying to feel or see it. I saw the diagram you attached and it seems like it would, I just can't seem to find it. The sub-frame bolt does come out and is over the chain allowing it to come into contact with it. I could try to shave it down and see where that gets me. I haven't tightened the chain just yet because I don't have wrenched right now, only sockets.

I tried adjusting my idle and I forgot the original position so I then tried to do the manuals guide on it and it seemed to work somewhat then it all went downhill. I turned the silver screw to 1.25 which the manual suggests then turned it counter-clockwise until it idled higher and that didn't work and it kept sputtering. My bike started to overheat so I moved the screw with the black plastic finger tightener to between 2.5 and 2.25 out and just turned the silver one out until the idle was where I wanted it to be. I feel this is completely backwards, or maybe it's right I just don't know, but it works as of now and it takes about 5 minutes to warm up with choke on then it's good to go for the rest of the day.

Surprise, surprise there's something else. I have been having an issue with my lights in that they will just sorta die out when I''m riding down the road. Sometimes they come back on with higher revs and sometimes not. It could just be coincidence. When it goes off it comes back on if I slap the light. It does this for the high and low beam. My bike is also set to only have lights come on when the engine is running. So when it's the light switch does nothing.
 

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