701 Oberon Slave change

NORTY FLATZ

NORTY FLATZ

expert rider
Joined
Mar 31, 2021
Messages
198
Location
NORTH SAN DIEGO CO.
Hi all, I have a bit of a problem. I changed out the OEM slave to an Oberon unit, and am having trouble getting a firm lever after refilling the M/C. Usually, I have good luck using my miti-vac and pulling fluid thru the slave nipple. Try as I might, I could not get the fluid to pull thru the M/C, via the slave nipple. The fluid should go down in the M/C res. So, the next thing I tried is a syringe and pushing fluid up to the M/C from the slave nipple. No change in the fluid level in the M/C here either. It should rise. So, is there a secret I need to do to get a firm lever, as I have basically no lever, atm. Right now, the bike isn't ride able.
 
When I had a similar problem the master needed a rebuild.

You could try opening that up and giving it a clean.
 
nampus said:
When I had a similar problem the master needed a rebuild.

You could try opening that up and giving it a clean.
Click to expand...
Thanks, I'm thinking the same. It's been replaced before, but I dunno if the mechanic used the proper fluid or not. Seems the M/C lid gasket is swelled, so the seals may be as well. Off to order a rebuild kit...
 
I'm finding that some Magura rubber seals swell when using DOT 4 or 5.1 fluid, as the cap recommends. So, I rammed fluid from the slave bleeder to the M/C. I now have a "lever" but it doesn't "feel" right. Feels like it's spongy. I tried putting it in gear and pulling the lever. It does disengage slightly, but not anywhere near what the clutch on my Tiger is. It completely disengages.
Here's a couple pics of my contraption.
IMG_8542.jpegIMG_8543.jpegIMG_8544.jpegIMG_8545.jpeg
 
Well, now I'm hearing that I need a "rebuild kit" for my M/C. So, I ordered one. It also appears that the fluid I used is NOT compatible with the seals. Some say, I need the "Magura Blood" fluid, so I have that on order too. Now, to wait for the parts/fluid to arrive, then try again with another syringe/vinyl tube....

This will be the 3rd M/C this bike has had in 10K miles....
 
Magura blood is mineral oil as far as I know, if your system is suitable for dot 4, you should not need magura blood.
What year is your 701? Is that 3rd master cylinder a stock master cylinder? If it is, it should use dot 4/5.1 not mineral oil.
 
I rebuilt my clutch master once, and decided then, that if it needed another rebuild I would just upgrade to an aftermarket clutch master. The stock magura stuff is crap if you ask me.
 
nampus said:
Magura blood is mineral oil as far as I know, if your system is suitable for dot 4, you should not need magura blood.
What year is your 701? Is that 3rd master cylinder a stock master cylinder? If it is, it should use dot 4/5.1 not mineral oil.
Click to expand...
It's a 2018.

With the "crap" M/C from Magura.

Never had problems like this, with any hyd clutch or brake system in 50 years. (Ok, so most of those may have been cable, but still...)

It's only had 2 M/C's so far, both OEM stock units. Should be receiving the "rebuild kit" tomorrow...
 
I was going to start the process today, but other things got in the way. I opened up the M/C cap and the gasket is HUGE. It's about a quarter inch too long now, so it has swelled bug time. I put the lid back on as I didn't have time to mess with it today. Maybe during the week.
Oh, here's what was occupying my day today...
IMG_8887.jpeg
 
Well, I left it alone, and then tried it. I haven't pulled the piston and seals out of the M/C as yet, but it seems to WORK. So, for now, I guess I'll leave it alone and ride it. It drags very slightly (not enough to creep forward with the brakes released.)
Well, I'm bamboozled at this point. But, at least I have another bike to ride...
 
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