More Problems - Clutch reservoir this time!

[Lotsokids]

So I think I got my carbs set up. I did the adjustments last night, then as I finished a heavy thunderstorm rolled in. The bike runs and revs good now. I got home from work hoping to try it out on the road, but when I opened the garage door, I was greeted by a big puddle of brake fluid on the floor from the clutch reservoir. It drained out the plunger, down my clutch lever away from the bike, so thankfully it didn't eat up my paint. NO PROBLEM I thought, since I already bought a rebuild kit a few months ago. So I pulled it all apart. That snap ring SUCKED to remove. It was so deep, I had to modify my snap-ring pliers to get it out. I cleaned the cylinder and installed all new parts - plunger, internal rubber seals, everything. Then I had some problems bleeding the clutch. I heard air escaping past the plunger's seal as I pushed it in. I kept working it, but then it started leaking. It will not even hold pressure. I took it all apart again and inspected everything. It's all clean inside, and the rubber seal is in good shape (and yes, installed the correct direction). Put it all back together, and still no pressure and still leaking.

Oh yeah, I live in Hungary, so I can't just run down to the store and buy another rebuild kit. This thing might not be back on the road until mid-August.

It's one of those very discouraging days!

[rktmanfj]

The FJ clutch slave is notoriously a bitch to bleed.

Many find success in using a large syringe to push fluid in from the bottom, through the nipple.

Randy T
Indy

[FJ111200]

Take off the hose at the reservoir, then fill the reservoir with fluid, then pump the lever and hold it in, then put you finger or thumb over the hole where the hose should be and release the lever, then release your digit and you should hear the cylinder suck, do this a few times until fluid starts to flow, then connect up the hose and start the bleed procedure and it should all work out.
Does for me.

[Lotsokids]

Take off the hose at the reservoir, then fill the reservoir with fluid, then pump the lever and hold it in, then put you finger or thumb over the hole where the hose should be and release the lever, then release your digit and you should hear the cylinder suck, do this a few times until fluid starts to flow, then connect up the hose and start the bleed procedure and it should all work out.
Does for me.

I did everything you recommended, and it's still not working. When I hold my finger over the hole (fluid line removed), it draws from the reservoir. I can also feel good pressure against the lever as I try to squeeze it with my finger still over the hole. I spent 1.5 hours bleeding tonight, and I stopped when my hands started cramping. This is HORRIBLE. Plus it's still leaking a little past the plunger seal. If I was in the U.S., I could probably get a hand vacuum pump or try the injection method from the bottom with a syringe or something. I've got nothing here. That's frustrating.

[andyb]

If it's leaking at the plunger, no amount of bleeding will make it right.  Temporarily working, maybe.

Either rebuild the master, or consider it an excellent time to upgrade to one with an adjustable lever.

[Lotsokids]

If it's leaking at the plunger, no amount of bleeding will make it right.  Temporarily working, maybe.

Either rebuild the master, or consider it an excellent time to upgrade to one with an adjustable lever.

I just rebuilt the master. It does hold pressure when I plug the hole, so I think because of the way the plunger's seal works (open end toward thf fluid), it needs pressure to hold the seal against the cylinder wall (like an oil seal). I just can't get the pressure.

[Harvy]

If it's leaking at the plunger, no amount of bleeding will make it right.  Temporarily working, maybe.

Either rebuild the master, or consider it an excellent time to upgrade to one with an adjustable lever.

I just rebuilt the master. It does hold pressure when I plug the hole, so I think because of the way the plunger's seal works (open end toward thf fluid), it needs pressure to hold the seal against the cylinder wall (like an oil seal). I just can't get the pressure.

Lotsokids, try this.
fill the clutch system from the bottom till the fluid comes out of the line where it attaches to the master.
Now there should only be minimal air in the slave.
now attach the line to the master, but don't do it up tight yet.....just crack it a little.
fill the master with fluid and while the top banjo is cracked, pump the lever a few times. When you see fluid coming from the cracked banjo, while holding the lever full squeezed, tighten the top banjo.
all the air is out of the top now because the pipe was full of fluid when you attached it, and the master has pumped the air out through the cracked banjo.
so now bleed the slave.....it should not take more than three or four pumps of the lever to get that last little bit of air out of the slave......just give it a tap between pressurising it so move the little bubbles to the bleed nipple.


From what I have read, this is a very common problem on the FJ master cylinder. It seems the it just wants to pump air backward and forward unless you give it somewhere to escape.

Give it a try....works for me every time.... never taken more than about 45 mins to do either master or slave rebuild kits and have it working.

Cheers
Harvy

[flips]

Hi there.

Did you use a yamaha rebuild kit or aftermarket kit?.I tried an aftermarket kit and it leaked out the plunger as you described.I then bought the yamaha one and bled the system.It worked for a while then gradually lost pressure.I bled the system again and again but same problem .I suspected the bore in the master cylinder was worn.Rather than spend a fortune on a new genuine part or take a gamble on a second hand unit, I bought on eBay a late model fjr unit and it works great and has the adjustable lever.I had previously upgraded the brake master to the fjr one as well so now they match .I think the fjr units have a bigger bore and displace more fluid.
Hope this helps
Jeff P

[Harvy]

I think the fjr units have a bigger bore and displace more fluid.
Hope this helps
Jeff P

Jeff, I believe the FJR master cylinder is 14mm...... while the OEM is 5/8" (15.88mm).
I am thinking the stroke is longer, thus moving a similar amount of fluid, with better mechanical advantage, thus the lighter feel at the lever.

Harvy

[flips]

I think the fjr units have a bigger bore and displace more fluid.
Hope this helps
Jeff P

Jeff, I believe the FJR master cylinder is 14mm...... while the OEM is 5/8" (15.88mm).
I am thinking the stroke is longer, thus moving a similar amount of fluid, with better mechanical advantage, thus the lighter feel at the lever.

Harvy

Hi Harvey.Thanks for the correction.I appreciate being pulled up if I'm talking crap!
I think i was getting confused with a honda master cylinder...but any way, the fjr master cylinders do seem to work better IMO
Cheers!

[andyb]

Smaller bore means less fluid is moved for a given travel at the lever.  Means that the useful bit of travel (i.e., point of clutch engagement or point of max braking) is much easier to find and maintain.  Total travel is restricted mechanically, varies according to how much was designed into that particular master.

In short, less bore means better leverage, and a bigger bore means more power (more fluid moved).

[Lotsokids]

...and NO fluid moves in my master cylinder, except past the seal. It's an aftermarket rebuild kit. I just went to a motorcycle repair shop today (Hungarian in his back yard). He said he would pick up my bike on Monday and bleed it for me for about $15. He was confident he would have it ready to go. He speaks no English, but I'm getting better at drawing pictures of my bike, not to mention the pointing and sound effects. It's pretty comical, actually. I ended up having to call a translator, though.

There's brake fluid all over the floor of my garage, and all over the plastic under the clutch reservoir. My paint will never be the same. What a mess.

Harvy - I would love to try to feed fluid from the bottom up, but I have no means to do it.

[andyb]

You can use a long tube to siphon to gravity feed from the bottom, rather than a syringe.

The system isn't really hard to bleed, it's just difficult to prime enough to get things started.

[RichBaker]

Unless you washed it off IMMEDIATELY, that plastic will be history..... I had a similar unfortunate experience a few years ago. the left scoop had several major cracks, the fairing was brittle and cracked over several months time. I had to replace it all..... 

[Harvy]

Harvy - I would love to try to feed fluid from the bottom up, but I have no means to do it.

They have vets there in Hungary don't they.....yeh they must have, seems to be plenty of horses about the place.......so go to the vet and get a plastic syringe they use for horses......no needle, just the syringe. Fit a clear rubber/plastic tube to the syringe and to the bleed nipple......there you have it.......you can now push the fluid into the system from the bottom. (works for the brakes too)

Cheers mate
Harvy