ST1300 clutch pooped?

JetRanger

JetRanger

Joined
Sep 1, 2024
Messages
80
Location
Waterloo Region, Canada
Bike
ST 1300 PA
Three weeks ago, I sprained my ankle which sadly delayed my first ride of the year.

Prior to that, I checked over the bike, ran it, made sure the clutch and brakes worked, reset the clock and added a new top box.
I also planned on changing the oil & filter before the first ride but life had other plans.

Becoming slowly more mobile, I've graduated to no crutches and climbing up the stairs in under 15 minutes. Today, I was able to go outside to see if I could get myself on the beast, get the sidestand up & down, hold the bike up, roll it backwards and use the shifter. All went reasonably well until I tried to put it into first gear: the clutch snapped back with no resistance.

Needless to say my heart sank as I envisioned a massive repair bill from the local Honda dealer.

I opened the reservoir on the clutch and found it almost empty! It was also filthy as hell. I cleaned it out and topped it up with fresh fluid and then gave it a couple of squeezes: I got normal resistance. Some air bubbled up as I released the clutch so I squeezed slowly (while tapping the hydraulic line) until no more air came back. I know that's not proper procedure but bleeding the clutch was on the agenda after the oil change. It shifted fine after that so I just went back and forth a couple of times and shut her down. I also decided my ankle wasn't ready to ride.

A few hours later, I thought I would try some mounting therapy and noted the sight glass indicated half full.

Am I correct in diagnosing this as clutch slave cylinder failure?
Is a knuckle busting, cuss filled removal and rebuild in my future?

This is not something that I am looking forward to.

I've seen Max Pete's post on this and will be studying it at length.
 
JetRanger said:
Am I correct in diagnosing this as clutch slave cylinder failure?
Click to expand...
Assuming that you have checked and there is no leak elsewhere in the system, yes.
JetRanger said:
Is a knuckle busting, cuss filled removal and rebuild in my future?
Click to expand...
Yes, yes, and no. The no is for the rebuild, just replace it with a new one.
 
JetRanger said:
Three weeks ago, I sprained my ankle which sadly delayed my first ride of the year.

Prior to that, I checked over the bike, ran it, made sure the clutch and brakes worked, reset the clock and added a new top box.
I also planned on changing the oil & filter before the first ride but life had other plans.

Becoming slowly more mobile, I've graduated to no crutches and climbing up the stairs in under 15 minutes. Today, I was able to go outside to see if I could get myself on the beast, get the sidestand up & down, hold the bike up, roll it backwards and use the shifter. All went reasonably well until I tried to put it into first gear: the clutch snapped back with no resistance.

Needless to say my heart sank as I envisioned a massive repair bill from the local Honda dealer.

I opened the reservoir on the clutch and found it almost empty! It was also filthy as hell. I cleaned it out and topped it up with fresh fluid and then gave it a couple of squeezes: I got normal resistance. Some air bubbled up as I released the clutch so I squeezed slowly (while tapping the hydraulic line) until no more air came back. I know that's not proper procedure but bleeding the clutch was on the agenda after the oil change. It shifted fine after that so I just went back and forth a couple of times and shut her down. I also decided my ankle wasn't ready to ride.

A few hours later, I thought I would try some mounting therapy and noted the sight glass indicated half full.

Am I correct in diagnosing this as clutch slave cylinder failure?
Is a knuckle busting, cuss filled removal and rebuild in my future?

This is not something that I am looking forward to.

I've seen Max Pete's post on this and will be studying it at length.
Click to expand...

Howdy @JetRanger: y
Yeah, that fluid had to go somewhere and I’d guess it is now in the little void-space between the engine case and the CSC. If you refill the master cylinder, it will work but the leaking CSC seal will just keep allowing fluid to escape into that void and eventually the space will be full and fluid will drip out of the weep-hole and onto the ground- and your clutch will stop working.

Soooooo…..buckle up for a clutch slave cylinder (CSC) job.

My advice:
- buy an OEM cylinder
- do not attempt to rebuild the old one - the kit costs nearly as much as a new CSC and the inside of the cylinder bore is likely corroded beyond redemption
- buy a new gasket
- buy new copper crush washers (I think you’ll need about six of them and they are cheap)
- buy a small tub of Vaseline to help stick the two hydraulic pipes and the stack of crush washers together
and
- DO NOT cross-thread the banjo bolts as they go into the various fittings.

Other than those points, get comfy on the floor and have a good light with you.

Please keep us posted.

Pete
 
Last edited:
MaxPete said:
Yeah, that fluid had to go somewhere and I’d guess it is now in the little void-space between the engine case and the CSC. If you refill the master cylinder, it will work but the leaking CSC seal will just keep allowing fluid to escape into that void and eventually the space will be full and fluid will drip out of the weep-hole and onto the ground- and your clutch will stop working.

Soooooo…..buckle up for a clutch slave cylinder (CSC) job.

My advice:
- buy an OEM cylinder
- do not attempt to rebuild the old one - the kit costs nearly as much as a new CSC and the inside of the cylinder bore is likely corroded beyond redemption
- buy a new gasket
- buy new copper crush washers (I think you’ll about six of them and they are cheap)
- buy a small tub of Vaseline to help stick the two hydraulic pipes and the stack of crush washers together
and
- DO NOT cross-thread the banjo bolts as they go into the various fittings.

Other than those points, get comfy on the floor and have a good light with you.

Please keep us posted.

Pete
Click to expand...
Awesome advice...

I shall report back after the scabs on my fingers and wrists heal and I can type again.
 
Amazon will sell you an assortment of crush washers for a few bucks. You can get either copper or aluminum. You will use maybe 4 of the washers in that kit and discover the rest fit nothing made by man. I'm kidding, of course, but unless you match up the id and od of the washers you need w/ Amazon's list of what is included, there are no guarantees that what you get will be what you need. The critical diameter will be the ID.
 
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This is an excellent photo (thanks for sharing @SupraSabre), and it sure demonstrates how simple it would be to R&R the slave cylinder - likely about a 5-minute job instead of two hours with the engine in the bike. As I noted in my original article, removing the engine is Step 1 of the Honda-approved method of CSC replacement, and doing that sure looks like a heck of a lotta fun. Fortunately, my shop labour rate is pretty low (like....$0.00/hr, if you don't count the BEvERages), so I will take the engine-IN option as pulling the engine likely takes several hours, and IMO, it risks damaging other stuff on the way out and back in.

For the uninitiated, the oil filter fitting is the big roundish thingy on the lower left corner of the transmission case (directly above that yummy-looking coffee cup), and the case clutch slave cylinder (CSC) is directly to the right of it.

Also visible are the small 6 mm bolts that secure the CSC to the transmission case, and you can just see the upper-left-hand edge of the green gasket poking out from between the body of the CSC and the trans case. The blackish bolt sticking nearly vertically out of the CSC is the banjo bolt for the short hydraulic pipe that operates the clutch when you squeeze the lever on the left handlebar.

NOTE: You will require TWO copper crush washers on that banjo bolt and THREE on the banjo bolt that joins the hose from the master cylinder and the short pipe that runs over to the CSC - a total of FIVE copper washers. There is a washer placed above and below each banjo connector (that's why you need five washers). Every decent motorcycle shop will carry them.

DO NOT cross-thread the banjo bolts going into the softish aluminium CSC body.

The starter motor is in the upper-right of the transmission assembly, just above the transmission output shaft spline that engages the driveshaft (on the right - about halfway up the trans case), and at the extreme lower-right is the splined shaft that operates the gearshift mechanism. The little black thingy between the gear shift shaft and the CSC is the speed sensor. Some folks have removed it to help with access to the CSC bolts, but I found that a short 3" extension on a 1/4" drive ratchet made access acceptable.

Anyway, this photo from @SupraSabre is a very useful addition!

Overall, this job takes most people around 1.5-2 hours, and it really isn't that big a deal. It is just a little awkward lying on your back and reaching up into the innards of the bike between the rear-wheel swingarm assembly and the back end of the engine-transmission and messing around with the crush washers and the banjo bolts is a bit fiddly.

Cheers,

Pete
 
My photo is when I was swapping out the 06 ex cop (good) engine with the 05 bad engine! While it was in this condition I took the liberty to replace all the seals in the back of the engine.

I DON'T recommend this way! LOL

20250430_4tractorholdFrame1.jpg

20250520_RideAroundBlock2.jpg
 
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