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Clutch help!

DAMN maintenance and repair thread; including Farkle Fests! :boohoo:
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juddspaintballs
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Clutch help!

Post by juddspaintballs »

I'm a little over a week out from going on a 3 day off-road trip with my 2000 250EXC. It's pretty new to me.

I rode it back in January with no issues with my clutch. I had a stock or Tusk stock-like lever on there. I can't recall which. It worked just fine. I could pull the clutch lever with the bike in gear and running and stop without bogging the motor. I could have the bike off and in gear and walk it around by pulling the lever. Everything worked as it should.

While I was down this winter, I replaced the lever with a Midwest Mountain Engineering Clever Lever. That is all I did. I adjusted it on a warm bike and I was able to use it to stop while in gear or walk the bike in gear while turned off.

I rode the bike off-road for a day last week. While riding, the bike started to get to the point that I couldn't pull the lever in while in gear and running and stop. It would bog down the motor and kill it with brake applied. When attempting to kick with the lever pulled and in gear, the bike would lurch forward. I couldn't walk the bike in gear with the lever pulled. I attributed this to bad adjustment on the new lever, did some trail adjustments, and was able to finish the day. The bike would still bog when stopped in gear and often kill it unless I fed on a little throttle to keep it alive.

Today I attempted to adjust the lever better. No change, perhaps even worse. I tore apart the master cylinder and cleaned it out. The seals on the plunger looked great: almost new. Reassembled the master cylinder, attached a hose to the bleed nipple at the clutch, and back flushed clean transmission fluid up into the master cylinder until the master cylinder was full of clean red transmission fluid and all of the bubbles came out. No change in the clutch disengagement. Still can't walk the bike in gear, still bogs down when stopped in gear, still lurches while kicking in gear (all with the clutch lever in, of course).

I put the Tusk lever back on. Same deal. No clutch disengagement.

Now what?
Jed Gregory
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gots_a_sol
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Re: Clutch help!

Post by gots_a_sol »

I'd pop the clutch cover off and inspect the frictions/plates for a broken one and see how the fingers on the basket look.
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Bucho
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Re: Clutch help!

Post by Bucho »

Im sorry Im no help.

Must be something else? I was able to change my clutch lever out for the same clutch lever and it worked fine. Didnt need any other adjustment.
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Boom Boom
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Re: Clutch help!

Post by Boom Boom »

Your slave cylinder might be failing or have air.
You can bleed from the slave bleeder to the master cylinder and still have air in the slave cylinder and not all that uncommon for the seals in the slave to fail and cause the problem you are describing.
I would pull the slave and use a little air to pop the piston out and make sure everything is clean and in good order.
Reassemble and make sure full of fluid before you reassemble and bleed again.
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thetable
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Re: Clutch help!

Post by thetable »

The Magura slave cylinder was somewhat problematic. There were a couple aftermarket options that redesigned the system. If I wasn't headed out of town tomorrow, I'd pull mine off my 450 and let you use it.

Surest bet in a hurry is to call all the local KTM shops looking for a complete slave cylinder assembly. They used that slave for an extended period, so availability shouldn't be too hard.

Short term fix is to find a replacement o-ring. Don't remember the size, but it should be easier to find and cheaper, but it is a temporary fix. It could last an hour, a day, a week, maybe even a month. The piston cocks sideways, scores the bore, and alas, you can't get pressure.
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juddspaintballs
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Re: Clutch help!

Post by juddspaintballs »

I went out and played around with things. I was using 15w40 motor oil in the transmission.

I took the clutch cover off and took the clutch all of the way apart clear down to having the basket out. Nothing looked bent, broken, or burned.

I took the slave cylinder out, depressed the piston all of the way in with a small C-clamp and held it there. I used my syringe and pushed fluid through the nipple up into the master cylinder. I used about 50cc of fluid total to ensure I had absolutely no air in there. I put the slave cylinder back on and closed up the master cylinder. It appeared that the push rod pushed against the springs enough to let pressure off of the plates.

I put the bike in gear with the clutch cover and bike off. Clutch lever in, no go. I took my finger and slid a couple fiber plates out towards the pressure plate. I could now roll the bike in 1st gear with the clutch lever in. I let the lever out and pulled it again and I had the same scenario. I did this a few times and I was even able to rock the bike forward and back with the clutch in and bike in gear and it would eventually free up and roll with noticeable resistance. I hear these always drag some.

Clutch cover back on, refilled the transmission with ATF (Mobil 1 3309). Warmed the bike up. Lurches when placed in gear (normal amount for all motorcycles I've ever owned). No stalling this time. I was able to roll the bike while in gear and clutch lever in. Rides around the driveway fine and doesn't seem to slip going uphill. Stops just fine in gear. Shut the bike down. Kicking while in gear still lurches it the first kick, but it will start on the 2nd or 3rd kick without lurching. Shut the bike down again and it will roll with noticeable resistance.

So, does it sound like the clutch pack needs replaced or is this normal?

Bottom line: do I buy a new clutch pack tonight so I get it in plenty of time before my trip?
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thetable
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Re: Clutch help!

Post by thetable »

Clutches don't grab on the way out, not the other way around. KTM clutches are the worst. My bike stalls on cold oil first shift out of neutral.
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gots_a_sol
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Re: Clutch help!

Post by gots_a_sol »

juddspaintballs wrote:Bottom line: do I buy a new clutch pack tonight so I get it in plenty of time before my trip?
Doesn't sound like you need a new clutch set, but it never hurts to have a spare set on hand just in case.
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Re: Clutch help!

Post by Space Ghost »

May not make a difference but I thought they used mineral oil in the clutch hydros. My 04 does.
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thetable
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Clutch help!

Post by thetable »

Space Ghost wrote:May not make a difference but I thought they used mineral oil in the clutch hydros. My 04 does.
I don't remember when the changeover happened, but the new bikes have brembo clutch hydros, which use brake fluid. For some reason, I remember reading there was some point where some models had brembos, and others had Maguras.
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