ST1100 - How to troubleshoot the clutch?

[wczimmerman]

My wife's ST1100 has started to become a bit difficult to shift into neutral and from 1st to 2nd when the bike is up to temp. I've been replacing the clutch fluid annually and carefully but the bike does have 73K miles so it's possible that something is showing it's age: master cylinder, slave cylinder, clutch plates, clutch springs? But I thought I'd ask here for steps to troubleshoot which may be helpful to others. I also looked in the ST1100 articles and didn't see anything of the sort.

@Igofar - It has Rotella 15w-40 in it and is pretty recent

 

[Larry Fine]

Does the engagement point of the clutch lever change with temperature?

 

[Uncle Phil]

Clutch lever bushing or slave cylinder going south.

 

[wczimmerman]

Engagement is reported by my wife and daughter (who ride this bike more than I do) as the same regardless of temp.

I do lube the clutch bushing though I could probably do it more often than I do.

 

[Ron]

It's about a 5 minute job to inspect the bushing. If that's it. they're about $15 from Honda.

#2 in the parts breakdown.

BUSH 22885-MB0-006

 

[oude geit]

Get bike on road, in 1st gear tach it up to 6 or 7000 rpm. Lean forward... Let go of clutch, if it wheelies the clutch is ok. Bad clutches shift easy, they have maximum gap, but they dont hold torque.

 

[Larry Fine]

Get bike on road, in 1st gear tach it up to 6 or 7000 rpm. Lean forward... Let go of clutch, if it wheelies the clutch is ok. Bad clutches shift easy, they have maximum gap, but they dont hold torque.

I hope you're kidding.

 

[jfheath]

If it is difficult to change gear then it may be because the clutch is not disengaging properly.
I usually start with the cheapest solutions before worrying about anything else.

1. The gear linkage needs lubricating - both ends.
2. The weep hole is blocked. This is at the 6 o'clock position in the joint between the clutch slave cylinder and the crankcase. Do not hold the clutch lever in. Poke it with a stick.
3. There is air in the hydraulic line. This prevents the clutch lever from dusengaging the clutch. Open up the clutch lever reservoir. Note what colour the fluid is. Use the pump, pump, pump, bleed technique. See below.
4. The clutch lever isn't as effective as it should be. Inspect the brass bush. When outting it back together, note that there is a hole in the side of the bush. Mark a line on the top to indicate where the hole is, so that you can be sure that the pushrod fits inside.
5. The slave cylinder seal isn't effective. Fit a new service kit.

Notes.

1. Easy fix, if you can get at it.
2. Fluid and oil can weep past their seals into the air space between the slave cylinder and the clutch. If this builds up, it can impede the movement of the piston in the slave cylinder. If the clutch lever is released there will be nothing that can be damaged. Use something fine that cannot break off. Stick it in, wiggle it about.
3. With a non return bleed tube in place, a jar to catch the fluid and a full reservoir - with the bleed valve closed pump the clutch lever a few times and an the last pump hold the clutch lever against the handlebar. Open the bleed valve and close it just before the fluid stops flowing. Repeat.
   The reason that this works best is that the pumping builds up a bit of heat and pressure; keeping the lever held in squeezes any air bubbles which makes the less buoyant and helps to detach them from the sides of the tubes. It closes off the compensation port, which means that fluid cannot escape back to the reservoir. The pressure of the clutch spring pushes the fluid through the tube. Once you have got a better feel at the lever, simply open the bleed valve and pump the lever repeatedly to get a continuous flow. Tap the hose a few times to dislodge bubbles and repeat.
   If the fluid is dark then it has been sitting a ling time. Flush all of it through, but this may suggest that so,ution #4 is required.
4. No comment see previous posts.
5. This isn't particularly expensive, and is easy to do, but takes a bit of time. Make sure you get a gasket with the kit. The right hand exhaust down pipe gets in the way of removing the cover, and it needs to be slackened off to gain a bit of mevement, and that requires getting at the tip over bars, so the left fairing has to be removed. All easy stuff, but it takes longer than it should. You may need gasket sealant if the mating surfaces of the cover and crankcase are not smooth, or have been damaged when scraping off the old gasket.

 

[Andrew Shadow]

Article [11] - ST1100 - Shift Linkage Tune-up | ST1100 Articles

I read an excellent article by Mark Frost on Mike Martin's website, documenting problems that Mark had encountered with his shifter assembly. Based on what I read, I decided to take the shifter assembly off my moto (2001 ST1100A) and have a look. Sure enough, I had the same problems that Mark...

www.st-owners.com

 

[ST Gui]

I'd start with the easiest bit — the clutch lever and bushing. Remove the nut and bolt and check the bushing for roundness inside and out. Same with the clutch lever. Personally I never has a worn lever but I've replaced two bushings over the years because the bolt hole was oblong not round. That cured my problem. It may or may not be the answer to yours but it's easy to check. I clean and lube all the surfaces then tighten the lever bolt 'till there's no play but the lever still moves freely. Definitely not a cure-all but well within my wheelhouse.