Time for a new clutch

[93Bandit]

My 850 has had a slipping clutch under WOT for the last ~6,000 miles. A few years ago I installed new OEM clutch springs and that seemed to fix it for a while, but now it's slipping again, but bad enough it's not much fun to ride. Any more than half throttle and it slips in all gears. When cruising on the highway, I can barely pass anyone because rolling into the throttle just sends engine RPMs to redline with no vehicle speed increase. Also, I'm using Rotella T4/T5 with no additives so oil shouldn't be the issue here. Bike has 33k miles on the original clutch as far as I'm aware, so it think it's just time.

OEM clutch plates are very expensive, so searching the GSR I see mention of EBC plates being just as good as OEM and cheaper. I plan to get EBC friction plates, but my question is whether or not I should replace the steel plates as well? Last time I had it open to replace the springs, I did not see any discoloration on the steel plates or other signs of overheating. I will inspect them again before ordering parts, but if they don't show signs of over heating can I reuse them? Or should I just replace them as well?

 

[Suzukian]

I've never replaced the steel plates. They have never been gouged though. I have (for my Yoshima CB458cc race bike) sanded from the center out wards, with a wire brush, lines to help the clutch grab. I don't think that's necessary in your case though. There is a measurement for them, but I've never seen a bike needed them. If I take the side cover off, and work on the clutch, I put in new friction plates regardless. You mine as well and you're in there. The wrong oil can cause them to slip. EBC makes good products, but for clutch plates, I always go stock. EBC would probably be fine though, their disc brake pads are good.

 

[rphillips]

Sorry, I'm not sure, but have never replaced a steel plate, that I can remember. Wondering how I've been so lucky. I've abused many GS clutches, busted a couple of clutch hubs and broke several fiber plates, but not had a slipping GS clutch except when I put Slick-50 in oil. Changed oil a couple of times and no more slipping. Now 2 GS clutch slipping threads in past couple of wks.

 

[Rijko]

My 850 has had a slipping clutch under WOT for the last ~6,000 miles. A few years ago I installed new OEM clutch springs and that seemed to fix it for a while, but now it's slipping again, but bad enough it's not much fun to ride. Any more than half throttle and it slips in all gears. When cruising on the highway, I can barely pass anyone because rolling into the throttle just sends engine RPMs to redline with no vehicle speed increase. Also, I'm using Rotella T4/T5 with no additives so oil shouldn't be the issue here. Bike has 33k miles on the original clutch as far as I'm aware, so it think it's just time.

OEM clutch plates are very expensive, so searching the GSR I see mention of EBC plates being just as good as OEM and cheaper. I plan to get EBC friction plates, but my question is whether or not I should replace the steel plates as well? Last time I had it open to replace the springs, I did not see any discoloration on the steel plates or other signs of overheating. I will inspect them again before ordering parts, but if they don't show signs of over heating can I reuse them? Or should I just replace them as well?

Did you measure plate thickness ?
Sometimes all it takes is replacing 1 or 2 fibers with thicker ones to get the stack height back in spec.

I don't know if your clutch had a hard life, but at 33K i do not expect the plates to be worn.
Maybe PO built the stack from different sets of old plates, some ok, some too thin.

 

[Cipher]

Adjust the cable per oem manual.

 

[rphillips]

Just remembering, there were clutch kits, for some of the old GS's, that had an extra friction plate, don't remember what mfg. had them. I never knew if the plates were thinner (thought they must be), nor how they were installed. It always seemed to me when installing, with an extra plate, there would have to be 2 fibers against each other.

 

[rphillips]

Just looked it up, APE was one clutch mfg. that offered extra plate clutch for GS1100's, reading about them I found they came with both an extra friction and an extra steel plate.

 

[Grimly]

I fitted EBC in 2019, with no trouble. The old plates were ancient and glazed, but had hardly any wear in them. I also fitted three slightly heavier springs and three OEM springs. All is peachy now.
One thing worth checking - over the years the old plates had shed fibres which had nearly blocked up the oil pickup strainer.

 

[Cipher]

I that cork or cooked flaked off glaze.

 

[93Bandit]

Did you measure plate thickness ?
Sometimes all it takes is replacing 1 or 2 fibers with thicker ones to get the stack height back in spec.

I don't know if your clutch had a hard life, but at 33K i do not expect the plates to be worn.
Maybe PO built the stack from different sets of old plates, some ok, some too thin.

When I had it apart to replace the springs, I did measure the friction and steels and they were all within spec at that time as I recall.

I don't know the history of the bike. The guy I bought it from claimed to be the second owner, but that's all I know. It had 24k on it when I purchased it. I don't think it had too hard of a life before because I don't recall any plates showing signs of overheating or excessive wear. But, it's been 4 years or so since I did that so I could be remembering wrong. I had considered replacing one or two fibers to get it back into spec if that's the issue, however if I'm going in there I'd rather just replace them all and be done with it.

 

[93Bandit]

Adjust the cable per oem manual.

The cable is adjusted per the oem manual. That's the first thing I checked.

 

[93Bandit]

I fitted EBC in 2019, with no trouble. The old plates were ancient and glazed, but had hardly any wear in them. I also fitted three slightly heavier springs and three OEM springs. All is peachy now.
One thing worth checking - over the years the old plates had shed fibres which had nearly blocked up the oil pickup strainer.

I came across you in other threads mentioning you use EBC fibers with no issue. Thanks for the tip concerning the oil pickup screen.

 

[93Bandit]

I'm going to tear it down and do a visual inspection and measure the plates. If the steels look fine I will just replace the frictions. I'm going to try the EBCs. Thanks everyone!

 

[rphillips]

Be sure to keep us updated.. Also, I've always heard of plates glazing, like mentioned up ^^^ there. I've don't remember hearing what causes it, but have heard the thing about wire brush, steel wool, or sandpaper to knock the glaze off works. Hoping when you get there, just for curiosity, you dry some of them off, and try to look for a glossy, glaze look on the plates.

 

[93Bandit]

Be sure to keep us updated.. Also, I've always heard of plates glazing, like mentioned up ^^^ there. I've don't remember hearing what causes it, but have heard the thing about wire brush, steel wool, or sandpaper to knock the glaze off works. Hoping when you get there, just for curiosity, you dry some of them off, and try to look for a glossy, glaze look on the plates.

I thought about trying to sand them but I think I'm just going to try new frictions so I can be done with it for good. I will dry a few off and take pictures though, for those who are curious. I'll see if I can see a glazed surface and if so, try to capture it with a camera.

 

[rphillips]

Yep, I'm curious about everything I'm not sure about... Thanks for helping the community possibly learn something.

 

[Cipher]

I thought about trying to sand them but I think I'm just going to try new frictions so I can be done with it for good. I will dry a few off and take pictures though, for those who are curious. I'll see if I can see a glazed surface and if so, try to capture it with a camera.

The Manual has a series of specifications for the plates and fibres. its quite shocking how little material there is to wear before slippage occurs. The measurement may well show sufficient thickness and a glaze may be root cause instead of friction material loss.

A sheet of glass and some silicon carbide wet dry sandpaper will break and remove glaze. I've done this and my fibres which were glazed by repeated quarter mile drags are just as good as new.
You can feel the difference in friction between fresh cork and glaze. its really quite marked.

Use a grit that just enough to break the glaze and finish with 1000. Rotate the fibre constantly and use little pressure.

 

[Grimly]

I that cork or cooked flaked off glaze.

Yeah, it was a kind of mix of flakes and fibres.

 

[Suzukian]

Glazing only happens if all the Clutch material is worn off and you get metal to metal contact.

 

[rphillips]

I never saw anything near that worn on any oil clutches I've seen. The fibers always look kind'f new. The oil clutches just don't seem to ware hardly at all. Years ago I did quite a bit of st., and some track drags. Always rode (slipped) the clutch taking off, but no ware, just busted hubs and broken plates.