2012 Sherco clutch

Discussion in 'Trials' started by broncobowsher, Mar 20, 2017.

  1. broncobowsher

    broncobowsher Long timer

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    After this weekend I need to find what is going on. The sometimes sticky after sitting I can live with. But I am getting a lot of clutch drag. And a touch of sticky even when warmed up that I don't remember before. Grab a handful of clutch and it still drives until you crack the throttle and shock it loose. I've owned it for 5 years and it was a demo for a bit before that. Just a bumbling Novice rider. The clutch feels correct. Feels like it is getting enough stroke that it should be fully releasing.

    I'm hoping to pull the clutch cover off soon and take a look around. So what should I be looking for?
    #1
  2. Boom Boom

    Boom Boom Been here awhile

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    Put in 3rd gear, front wheel against a solid wall and give the clutch a good hard work out, then change the oil. That might take care of it without needing to have a look.
    #2
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  3. jonnyc21

    jonnyc21 Trials Ninja

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    I would guess your seeing two things combine. 1st is the oil might just need a change and second would be glazing of the plates. (slim chance the glue between the fiber pads is rubbing on the steal disks)
    The glazing will cause the pads to be smooth an this creates an almost suction like affect sticking them to the steals. This can be fixed by sanding the fiber plats with some sand paper, or the 3rd gear wall trick might work (haven't tried that however)... Oil, well change it to improve that side of things...
    #3
  4. broncobowsher

    broncobowsher Long timer

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    3 oil changes and it isn't getting better. Even tried some motorcycle transmission oil I had instead of ATF with no change. So far the advise is they clutches are not glazed enough and need some abuse, or they are too glazed.

    Either way it is sounding like everyone is pointing to the clutch frictions and steels. Maybe just order up a clutch kit and have it handy before I open it up?
    #4
  5. motobene

    motobene Motoing for 46 years

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    First make sure your clutch lever is adjusted well.

    Pull the clutch cover off (4 screws and a delicate small o-ring). Cover off, watch the pressure plate move when you stroke the lever. Does it rise evenly? It should. If not, move springs around until it does.

    You'll like your clutch much more if you remove two springs across from each other. Leave the screws and washers for the springs out too. Lose two then move spring around for even rise.

    Another thing that causes drag is uneven thickness or messed up fiber plates. Pull the plates out (record their order) and inspect them. You probably have two types of fiber plates, one without notches in the tangs and one with.

    Measure the plates. Find the thickest spot on each fiber plate and reassemble the clutch clocking the thicker area of each plate 120 degrees apart. This requires calipers or better yet a micrometer. The thickness difference should be minor.

    To get rid of sticky clutch (plates worn too smooth), with 120-grit sand paper very lightly sand the fiber and metal plates to put small scratches on the mating surfaces.

    Refill with Maxima MTL 80-weight gear lube. Trust me. This specific oil is the tits for Sherco clutches.

    If you think you need new plates, get them from RYP. Metal plates if not warped or gouged can typically be re used.

    The later clutches have 2 or 3 race plates, and the balance the long running standard plates (6 fiber plates total). Fiber plates aren't cheap, so you should do the above tweaks first.

    I can't cover all the details, but this should help you.
    #5
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  6. jonnyc21

    jonnyc21 Trials Ninja

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    Well that eliminates the oil, so then yes the clutch pack work as indicated by bene is your best option.
    #6
  7. broncobowsher

    broncobowsher Long timer

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    Thanks Bene! Now to find a little time to actually dig into this.
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  8. broncobowsher

    broncobowsher Long timer

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    Follow up...

    Finally get around to getting the cover off. The pressure plate had a little rock to it as the clutch was pulled. Went ahead and pulled the clutch apart. The steels looked like they still had a matte finish to them. Compared to the non-wear area I thought they looked correct. Smooth, flat, nothing looked amiss.

    Pulled out the mic and did a quick check of the fibers and frictions as I put them back in. For the most part everything came in within .001" all around. And that much error could be me just going over it quickly. When I am quickly checking and getting inside half or a quarter thou I didn't see anything to worry about.

    Put it back together and cycled the clutch and the pressure plate still rocked. So taking your advise I started playing with springs, moving stuff around. Figuring the side the lifted first was the softer springs and the side later was the stiffer ones. That didn't level off the lift. So started thinking that two springs combined were either too stiff or too soft. So started playing with moving multiple springs at once. At one point I had 2 springs out 180° apart and suddenly the pressure plate was lifting very evenly. Snugged up the 4 bolts that were still in there and put the cover back on.

    I happen to have an open bottle of fresh brake fluid, so a little extra time to bleed the system just for grins. Didn't change the feel as I bleed it.

    With the engine off and engaging the clutch the back tire is locked up, that is good.
    Grab a handful of clutch and rock the bike, tire is still locked up and slides. But a little nudge of the tire will break the clutch loose and at this point I can roll the bike in gear. It is dark now, I don't even see moonlight. Going to have to wait until tomorrow (or later) to see if this did any good.
    #8
  9. broncobowsher

    broncobowsher Long timer

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    Went for a ride in the back yard last night. Rode until it was dark. It's going to take a little bit to change to the feel of the 4 springs. But overall it is fixed. Feels like new again.
    Thanks again!
    #9
  10. MT 007

    MT 007 Adventurer

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    I love happy endings !!!
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  11. lineaway

    lineaway Long timer

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    Go out and ride in 4th or 5th. If you trail ride at all you will be putting those two back in.
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  12. motobene

    motobene Motoing for 46 years

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    Lineaway, you like to swoop in and put some fear in folks about the minus two springs mod. I mean, 'trail ride at all' is a pretty dogmatic statement for the many of us who have been running 4 springs on a variety of bikes for a very long time.

    The only thing to fear is ear itself :-)
    #12
  13. lineaway

    lineaway Long timer

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    Bene. I just did this on my own Beta ( the 2010) no bueno. Until you ride it on a loop you have no idea if it works or not. Sure, 1st thru third putting around the yard it works great. I sweated both the recent nationals using my own springs. So I mainly putted around the loop.
    #13