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Discussion Starter · #1 ·
I have an 08 450XC that I got recently, and I noticed that when I fully pull in the clutch lever and go into first gear, the bike starts rolling forward slowly like the clutch is partially engaged. At first I thought the hydraulic system was poorly bled, but after rebleeding, the clutch lever was nice and pressurized but I still had the same issue. Could this be something with the clutch plates or basket? Any help would be greatly appreciated. I included some photos of the clutch slave.
 

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Have you tried adjusting the clutch cable yet? If I remember right from when I had my 525xc there should be a black adjustment dial on the lever. It’s been a while though I could definitely be wrong. I know when I had mine it would roll just a little and it hated to start in anything but neutral.
 

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Have you tried adjusting the clutch cable yet? If I remember right from when I had my 525xc there should be a black adjustment dial on the lever. It’s been a while though I could definitely be wrong. I know when I had mine it would roll just a little and it hated to start in anything but neutral.
There's no cable to adjust as it is a hydraulic setup. The dial behind the lever just adjusts the reach distance between the bar and the lever.

If it typically does it when it's "cold" the first time you put it in gear after starting and goes away once warmed up, that is pretty normal for these. The oil gets squished out from between the clutch plates when they sit and they kind of stick together. Especially if you're not riding it regularly. You can give it some extra throttle when you drop it in gear to make the plates break loose and not kill the engine.

If it seems fine for a while, then you have the problem, and you are loosing fluid out of the master cylinder and can't see a leak, then the slave cylinder is leaking into the engine. This is a fairly common issue after some time/hours. KTM doesn't offer a rebuild kit for the slave cylinder so you have to replace the whole thing if that's the case. Some guys have sourced their own O-rings to rebuild them.

Another possibility is that the clutch plates are just worn past spec. and the clutch can't disengage properly.
 

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That’s a nice thought but I think he needs to give us some more information first. Are you using mineral oil in the master cylinder? And do you notice if the level of the mineral oil is slowly dropping? That would be an indicator to the slave cylinder seal being bad, if it’s not leaking then your slave cylinder is fine and you’re probably needing to get some new fibers and plates. But you could also inspect the ones you have for wear. Is the bike new to you and did the previous owner say they did anything aftermarket to the bike?
 

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Discussion Starter · #6 · (Edited)
The previous owner owned the quad for about two years and he hardly ever rode it. Ever since he bought it he was experiencing this issue and so he replaced the clutch master cylinder, hydraulic cable, and the clutch slave cylinder but still had the same issue. I then bought it from him, tried rebleeding the system (with Magura blood mineral oil), and it still had the same problem. The problem does not depend on temperature from what I can tell. The quad can be cold or warmed up and it will do the same thing.
 

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It's likely in the clutch pack itself then if all of that was replaced and bled properly. Plates are worn thin, grooves worn in the inner hub not letting the plates separate properly, warped pressure plate, bearing going bad inside the basket,etc... Baskets are steel in these if I remember right so likely not a problem with that. Won't really know until you pull the cover and start looking at parts.
 

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Discussion Starter · #8 ·
It's likely in the clutch pack itself then if all of that was replaced and bled properly. Plates are worn thin, grooves worn in the inner hub not letting the plates separate properly, warped pressure plate, bearing going bad inside the basket,etc... Baskets are steel in these if I remember right so likely not a problem with that. Won't really know until you pull the cover and start looking at parts.
Oh ok. I might pull off the cover and give the clutch a look tonight
 

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Discussion Starter · #9 ·
I took off the clutch cover, and the first thing I noticed was how milky the oil looked. I've never replaced clutch fibers before, so I'm not exactly sure how to tell if they're in good shape, but after taking off the fibers, I definitely noticed the very first fiber had a nice big gash in it, but I'm not sure about the rest. On the clutch basket, I did notice some marks but I couldn't really feel the marks with my finger.
 

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I have the same issue currently. But mine only happenes when cold as far as the shift into first killing the engine. But I keep losing pressure in the clutch. And my fluid is milky. I dont seem to be dropping fluid level. And if it sits for a few days and then I grab the lever the clutch is normal. Only seem to lose pressure once it warms up.
 

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Milky oil is caused by water. Is your coolant low? I know a lot of people have said to look at your clutch pack but you also need to look at the clutch springs to see if they have fatigued.
 

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Discussion Starter · #15 ·
Milky oil is caused by water. Is your coolant low? I know a lot of people have said to look at your clutch pack but you also need to look at the clutch springs to see if they have fatigued.
I just checked out the coolant level, and there was coolant, but it was not topped off to the top. Also I took a photo of the clutch springs, but I'm not sure how to tell if they're worn or not.
 

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the only way to check both the springs and the clutch plates is to use a micrometer and measure to see if they are still within spec. Repair manual for the '08 has the spec tolerances in it (google it up - there are plenty of links to download the workshop manual).

Second: that oil is not good. Could be left over condensate, but I doubt that. Start with fresh oil, and if it winds up like that again you have a leak getting water into the system - with the most likely culprit being radiator fluid...can be as easy as a gasket, or a lot more painful to chase down.
 

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^ what Squish said.

With that big gash in that fiber plate I'd be replacing plates regardless if most of them are within spec. Does the pressure plate surface that rides against the plates look like it's making even contact? I had one warp that was only making contact about 1/2 way around.
 

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Discussion Starter · #18 ·
^ what Squish said.

With that big gash in that fiber plate I'd be replacing plates regardless if most of them are within spec. Does the pressure plate surface that rides against the plates look like it's making even contact? I had one warp that was only making contact about 1/2 way around.
I'll need to check the pressure plate. I went ahead and ordered a new clutch and clutch springs. I also bought a replacement o ring for the slave cylinder. I'm going to try installing the new clutch and rebleeding the hydraulic system with a syringe.
 

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Discussion Starter · #19 ·
I put in a new clutch and tried to put the used green seal back on the piston, but it would simply not fit in the slave cylinder, so I tried some o rings I bought, but those ended up being too small where hydraulic fluid would pass right by it into the engine. I realized that the "milky oil" was actually the engine oil and hydraulic fluid mixing. That got me looking for a rebuild kit on the slave cylinder. Has anyone tried this rebuild kit on eBay? It specifically says it will fit a 525XC ATV:

Link: https://www.ebay.com/itm/CLUTCH-SLA...rstClass!98663!US!-1:rk:1:pf:1&frcectupt=true


Also, is there supposed to be a spring between the piston and slave cylinder? I'm wondering why this green seal no longer wants to fit in the slave cylinder...

Automotive tire Machine Auto part Wrist Engineering
 

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26$? Go for it.... see if it works. Seems to use a o-rings instead to seal on the piston.
If that Doesent work you could cough up the money for the new slave from KTM BUT sigutech makes a high quality one with replaceable o-rings for just a little more than what the ktm one costs, and the sigutech is rebuildable!
 
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