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Only slips when running hot or in the power band its got a new clutch braided line oberon slave and rebuilt master I decided to throw parts at the problem and she's still got a slipping clutch I don't know what to do!!
 

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is it a stock master? did you clean it all out completely when you rebuilt it?

does it have a stock lever on it? or a crappy aftermarket?

what engine oil are you using?
 

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Discussion Starter #3
Yeah I did clean the master has mobil 1 4t and it does have real cheap levers on it just couldn't see how it would make a difference
 

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Put the stock lever back on.

If the lever is pressing against the plunger at all it could keep the system closed. If the system is closed the fluid will expand as it heats and partially disengage the clutch instead of migrating to the reservoir.
 

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Make sure it's bled properly. Try reverse bleeding the slave cylinder, the Oberon slaves can be hard to bleed....notorious issue on Aprilia RSV's. Also the Oberon in conjunction with the cheap lever may be making it worse. Aftermarket slave cyclinders reduce lever pull at the expense of the amount of space used to disengage the clutch. This can be negated by moving your lever all the way out to increase the lever pull distance.

I recently removed my Evoluzione slave off my RSV for this very issue.
 
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Bopp46m, did you ever get this figured out? I'm in the same boat. 2000 SP1 with 3500 miles on it. I've replaced the friction plates (OEM) and springs (EBC), cleaned/checked the lifter rod, done two oil changes (before the new plates went in and they were soaked overnight) with Motul 4T 7100. OEM levers and I rebuilt the clutch master cylinder with an OEM kit. I took apart the slave, cleaned it and put it back together but didn't replace any parts as everything looked good. I've thrown over $300 at this but still no joy.

Basically, the bike runs fine for the first 15 minutes. But then if I stop and get back on... the clutch slips and sometimes it won't even pull off the line. When I eventually get it going, some good hard downshifts seem to resolve the problem so not sure what that's pointing to. Would love some help with this mystery.
 

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Check for a clogged return port in the master.

Pull the reservoir off and make sure both ports below it are clean.
 

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Return port plugged solid. 🤬

Screw holding the clutch reservoir stripped out so I needed an extraction tool to remove it. (I remember ignoring that part when I rebuilt the master.) With it off, of course I could now easily see that the return port was completely blocked. It was the little tiny hole in the bottom of the bigger hole (in the middle)

Here's the blockage:
IMG_20200523_133016.jpg

I used some 26 gauge nichrome wire (my son's hotwire kit) to get in there and clean it out:
IMG_20200523_135959.jpg

And lookie lookie... that tiny little hole makes an RC51 work surprisingly well:
IMG_20200523_143953.jpg

Went for a good long ride with a couple of stops and had absolutely zero problems. Wibbly... I owe you a beverage, kind sir. I've been wrestling with this thing for a couple months now and was getting ready to throw in the towel. Sorted now. Cheers.
 

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no problem man. it's a common issue. when the port plugs it closes the system. as the clutch fluid heats and expands it has nowhere to go (it would normally just flow into the reservoir) so it extends the slave and disengages the clutch.


glad it's all sorted out.
 
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