Soft Clutch lever! Please help

[Mr.E]

Many thanks John & Peter, bike is still off the road for Winter so will add this job to the small list.

Edit. Parts now on order from Dave Silver and looking forward to getting in there.
Been in this area before to refurb the gear shifter last Summer so I sort of know where everything is...

 

[Igofar]

Many thanks John & Peter, bike is still off the road for Winter so will add this job to the small list.

Edit. Parts now on order from Dave Silver and looking forward to getting in there.
Been in this area before to refurb the gear shifter last Summer so I sort of know where everything is...

When I get a few minutes, I'll send you a list of parts/tools you'll need to replace it.
Your gonna need (3) crush washers, (2) alignment dowels, a gasket, an oil seal, and a speed sensor O-ring, and some Dot4 brake fluid.
You'll also need a 16 inch long (amazon) flex head/ratcheting wrench in 12mm, a 1/4 inch drive 8mm SWIVEL socket (not a swivel adaptor) an 8 and 10 mm wrench, two 6 inch 1/4 inch drive extensions, or a 14 inch long one, and a small block of wood 1/2 x 3/4 inch to hold everything in place.
A center jack, or auto jack to lift it slightly to move the center stand around.
You'll also need an oil filter and engine oil.
I've changed these in less than an hour now, once you know all the little angles you'll need to access.

 

[Mr.E]

Thanks for the info Larry, I've had a good read through the link from Peter (a few times) and feel confident to do this job.

 

[motornut]

I have run into difficulties bleeding a circuit from the bottom I don't have a silver bullet for bleeding that makes it easy since the air tends to let the fluid stay in the hose and let the fluid bypass it. I have had good luck by bleeding the master cylinder after letting it sit long enough for the air to rise to the top.

 

[Fdcarlin]

I think my thread got hijacked while waiting for my master cylinder rebuild kit to arrive i guess i should also address the slave cylinder… do i need to replace it, or just re-seal it?

 

[motornut]

Rebuilding the master cylinder will eliminate that as a problem. The slave cylinder is something that needs to be determined after it is taken off and inspected for damage to the bore. I have resealed mine with success, If you have time to wait for parts

 

[motornut]

Start out cheap and easy, there is always time to escalate

 

[Fdcarlin]

Start out cheap and easy, there is always time to escalate

TRUE, im just thinking of the bike being 19yrs old. a couple hours and a couple hundred bucks for peace of mind

 

[Igofar]

Much easier to deal with it in your garage where you have light and tools, than on the side of the road when it goes out completely etc.

 

[MaxPete]

I think my thread got hijacked while waiting for my master cylinder rebuild kit to arrive i guess i should also address the slave cylinder… do i need to replace it, or just re-seal it?

I would say that you likely need to replace the slave cylinder - and don't bother trying to replace just the seal.

The ST1300 clutch slave cylinders seem to be going bad pretty regularly these days (the bikes are all getting to be 15-20 years old) and they get pretty grimy and gummy up in there and some have shown corrosion as well. Mine, and I think that every single slave cylinder that others have replaced, has come out pretty badly damaged by age, engine heat, road muck, and dried-up hydraulic fluid (really it is just brake fluid). All of this just ruins the seals and seems to corrode the pistons and the cylinder bore itself as well - so replacing just the seals would be false economy.

My advice is, don't mess with it - just replace the whole thing with a new one. The cost difference between a rebuild kit (new seals etc.) and a whole new cylinder is minimal.

As for the master cylinder (i.e. the control end of the clutch "circuit" - the one mounted on the handlebars), well, I am not sure that anyone has found that they ever seem to fail - but perhaps they do.

The point is that the master cylinder lives in a much cooler and cleaner environment - and so, while there is no harm in replacing the seals, it is much more likely that your problem is the slave cylinder than the master, from what people on this forum have experienced.

 

[Fdcarlin]

I would say that you likely need to replace the slave cylinder - and don't bother trying to replace just the seal…

My advice is, don't mess with it - just replace the whole thing with a new one.

Good advice. I will order the slave cyliinder today. I already ordered the master rebuilt kit so i may as well do that too.

 

[MaxPete]

Good advice. I will order the slave cyliinder today. I already ordered the master rebuilt kit so i may as well do that too.

Another point Frank: the slave may not be leaking now - but it likely will soon. See my CSC R&R thread for the reason why - it makes perfect sense when you stare at how it is built.

Keep us posted and good luck with it. Remember that brake fluid will absolutely wreck the paint on your fuel tank - or anything else you spill it on.

Pete

 

[motornut]

The slave cylinder won't make the master cylinder fail because the failure point is down low. The master cylinder failure will allow contaminates into the fluid which migrate to the slave cylinder when you bleed it. Make sure the master cylinder is completely flushed and clean before opening and working on the slave or just about anywhere in the system,

 

[Larry Fine]

I had the exact same problem with my '01 as the OP. When at cool or normal operating temperature, the clutch worked perfectly. As it slowly got hotter, like at the Ride Like a Pro class, the lever free-play travel grew to the point that the engine would stall if I stopped.

Either letting it sit until it cooled or riding around until it returned to normal temperatures would slowly bring normal clutch operation back. Pumping the lever barely had any effect. It really seemed to be based on clutch fluid temperature and not mechanical interference.

Flushing the fluid, using a vacuum pump at the clutch, made all the difference. I have since gotten the bike hot enough to run the fan, and there has been no hint of the problem returning. I haven't even thought about it until reading this thread. I blame water in the fluid.

 

[Fdcarlin]

I am in the middle of replacing the csc now, it is actually really easy to remove. But getting my hands in there to clean the old paper gasket is the hardest part!

 

[Fdcarlin]

Bike is back to normal. Slave cylinder replacement solved the soft clutch issue. The job was not as hard as i expected. The flex head 12mm ratcheting wrench was a must for the banjo bolt, and a exacto knife+ a solvent is useful for removing stuck on old gasket.

 

[Igofar]

Now if you pull the old piston out of the housing, you'll probably see a grey wear mark, which is where it was wearing metal on metal, because all that crap tilted the piston
A much easier method (and safer for the aluminum housing) is NOT to use a razor blade or exacto knife on it, but use a thick/sharp wood chisel. You'll find the chisel will seat square and flush against the flat shoulder that is hanging off the housing, then simply push straight up, and the gasket will usually jump right off (think of a plow).
Using a small block of wood to hold the housing into the case between the part and the shaft housing allows your hands free, then use a quarter inch ratchet with a long extension and a swivel socket for the three bolts.
Then when lining up the banjo bolt, crack the bleeder pipe mounting bolt under the coolant overflow tank, and it takes all the bind off of it, and allows it to seat very easily.
But you probably already found all this out
Good job.
How did the Oil Seal look in the back of the engine?

 

[jfheath]

Well done for getting it sorted, and thanks for posting the results of your efforts.

I'm not looking forward to the day when I may have to do mine. I live in the hope that my annual flushes will stop things from getting grotty in there. I've done the 1100 before - but the Clutch Slave is at the front. I have big hands and getting in at the rear would be very awkward. But I do need to take my centre stand off one day soon ... and I may bite the bullet and see if the swing arm can be removed to gain access.

I've not quite worked out what will keep the bike upright if I take both off. Marty McFly's hovver board ?

 

[motornut]

TRUE, im just thinking of the bike being 19yrs old. a couple hours and a couple hundred bucks for peace of mind

I had Peace of Mind once in high school, but it took a half of a lid to get there. Can't afford the stuff now, wouldn't even if I could.