Slave/Clutch master mystery

[chainsaw936]

Hi All, I've been struggling to get my 89 back together after updating the shift detent from RPM. Decided to replace the clutch slave while I was in there, which turned in to me finding the pawl spring on the shift shaft was shot (after everything was back together) and the bike would not down shift on 1st try everytime. So here goes my issue today that I can't figure for the life of reading the service manual so many times, I may have the clutch section memorized.

Install new slave assembly, pumped fluid down through until I could MityVac from the bleeder nipple then pulled the slave back off and reverse burped the piston carefully to release all the air. All is good, no air bubbles after 2-3 extensions of the piston and then carefully pushing the piston back in. Piston moves out correctly and all seems correct, but then I bolt the slave back on the bike, pump the lever a few times and the lever feels like a really good front brake, NOT a clutch lever? I take the slave back off pump the lever, moves freely and the transmission shaft the slave pushes to actuate the clutch plates moves in and out freely as it should? 

I thought, maybe the short push rod fell out inside the clutch assembly and was binding but drained the oil from the bike, pull the cover and all is as it should be. What am I missing gang? I did have my buddy start the bike last weekend without the clutch slave on the bike and as oil pressure built/warmed up, oil came shooting out the side of the bike. Thankfully, I was standing close by and killed the motor after a cup of oil came out of the engine. He felt like a boob but honest mistake. Could this have moved something inside the clutch/basket, transmission shaft that is the culprit?

I'm at a loss on where to go next with the problem. Thanks for the feedback.
Shawn

[Pat Conlon]

Hi Shawn, it sounds like you are installing the slave with the piston in the out (extended) position...it's needs to be retracted, or in the in position...
Take the slave off, leave the line connected, open bleeder port, with your thumb, push in the slave piston (be ready...fluid is gonna squirt out of the bleeder) hold piston in while closing bleeder port. The piston should stay in (retracted) when the port is closed.
Don't touch the lever.
Reinstall the slave, the piston should still be fully retracted.

Now pump the lever...the master should now send fluid down to the slave to push the piston out against the clutch rod.

[chainsaw936]

Thanks Pat, I'll give it a try tomorrow and see where we end up from there. Appreciate the help!

[Millietant]

The very first time I took my clutch slave off to check the seals i couldn't even get the slave back in place because the piston was too far out in the bore. My first instinct was to force it into place by tightening the bolts, but luckily, before i picked up a spanner, I had a re-think.

I think Pat is likely right on the money in that the piston needs to be seated right back in the bore when you bolt the slave back in place, otherwise you're just trying to separate the clutch plates too far when you're pulling the clutch lever in.

[Old Rider]

The very first time I took my clutch slave off to check the seals i couldn't even get the slave back in place because the piston was too far out in the bore. My first instinct was to force it into place by tightening the bolts, but luckily, before i picked up a spanner, I had a re-think.

That is exactly what i did about 30years ago when trying to install a brand new clutch slave i tightened the bolt further and further trying to get the slave all the way in then a big bang and brake fluid splashed out .Strange the treads not got stripped but that bike was almost new ...Went down to the dealer and told them and got a new one 
Do it like Pat says with the bleeder open

[chainsaw936]

Thanks to everyone, always a good learning experience, but costly

Could have been worse.

[fj-f3a]

Shawn
I always get worried when I read these sorts of stories.
Have you checked that the orifice in the master cylinder is completely open when the clutch is engaged. (Hand off the lever.)
With the cap removed from the master cylinder reservoir, do you see a small quantity of fluid spurt from the orifice when you activate the lever? (Be careful)
With the slave cylinder removed, you should be able the push the piston back without releasing the bleed nipple. The fluid should return to the reservoir.
If not, you have a problem.

The following link is to an article I submitted in 2018.

http://www.fjowners.com/index.php?topic=17884.0

Personally, I always add the brake fluid after the slave cylinder has been installed.

If you can not push the cylinder back without releasing the bleed nipple, you may have overfilled the system.
Try removing the reservoir cap and pushing the piston back. Again, be careful.
The coil spring between the slave cylinder base and the piston is to keep the piston against the push rod at all times.
If you do push the piston back, it will return when you release you finger.

I can not stress the importance of the orifice being open on both the clutch and especially the brake Master cylinder when the leaver is released.

Gavin

[chainsaw936]

Shawn
I always get worried when I read these sorts of stories.
Have you checked that the orifice in the master cylinder is completely open when the clutch is engaged. (Hand off the lever.)
With the cap removed from the master cylinder reservoir, do you see a small quantity of fluid spurt from the orifice when you activate the lever? (Be careful)Yes, checked that right away and it works as it should.
With the slave cylinder removed, you should be able the push the piston back without releasing the bleed nipple. The fluid should return to the reservoir. Fluid returns as it should, BUT the piston walks itself back out from fully seated position. Piston is under pressure to keep contact with the tranny rod so makes sense but when I install the slave on the bike, it's extended too far and creates a lever that is more like a perfectly bled front brake. I did rebuild the master on front brake because the piston was worn and created a notchy feel under braking. Works great but I'm guessing the clutch master may be faulty too, allowing fluid past the seals, pushing the piston out gradually? Going to rebuild it when RPM gets kits back in stock.
If not, you have a problem.

The following link is to an article I submitted in 2018.

http://www.fjowners.com/index.php?topic=17884.0

Personally, I always add the brake fluid after the slave cylinder has been installed.

If you can not push the cylinder back without releasing the bleed nipple, you may have overfilled the system.
Try removing the reservoir cap and pushing the piston back. Again, be careful.
The coil spring between the slave cylinder base and the piston is to keep the piston against the push rod at all times.
If you do push the piston back, it will return when you release you finger.
Sounds like maybe my slave is working correctly then, which points the finger back at the master or the piston spring in the slave is worn?

I can not stress the importance of the orifice being open on both the clutch and especially the brake Master cylinder when the leaver is released.
Thanks for weighing in with your feedback, maybe my responses above shed more light on the issue because I'm changing everything out as I go to find the gremlin.
Gavin