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How to correct Beta clutch drag.

Discussion in 'Trials' started by lineaway, Apr 5, 2019.

  1. 2whlrcr

    2whlrcr gooligan

    Joined:
    Jan 30, 2005
    Oddometer:
    15,989
    Location:
    Dubuque, Iowa
    This happened with a 2006 Sherco that sat for a long time. Trying to break the clutch free didn't work. Had to physically pull the plates apart and we just put new ones in for good measure.
    #21
    Norman Foley likes this.
  2. funmachines

    funmachines Adventurer

    Joined:
    Mar 1, 2009
    Oddometer:
    33
    Location:
    Northern Cal
    Just took at quick look on McMaster Carr - they have .625 ID x 1 in OD shims in all kinds of thicknesses. 16 mm is about .630 in and tolerance on .625 ID shims is 0 to +.011 in and 25.4 mm is 1 in so it probably works fine. I'm going to get a couple and try it out. Clutch fix and different oil helps the sticking go away faster but still happens. Maybe this does it better.
    #22
    Nobade likes this.
  3. lineaway

    lineaway Long timer

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    Oct 1, 2011
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    nm
    So far I have not had time to try my third shim. Everything good so far, and no slipping at all. Might as well wait and order the M. carr set as I am going to try new springs too.
    98126A035 is an 18 pack.
    #23
    jonnyc21 likes this.
  4. motobene

    motobene Motoing for 49 years Supporter

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    Mar 9, 2013
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    7,402
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    Wichita Mountains SW Oklahoma
    Sticking is not really related to the amount of at-rest axial play between the slave cylinder and pressure plate. That's more a plates surface condition issue. If you have less slop, however, pressure plate lift will be greater.
    #24
  5. tightwoods

    tightwoods Didn't need that dab...

    Joined:
    May 16, 2007
    Oddometer:
    23
    Location:
    PA
    I checked for this on my 2017 4T Factory and it doesn't have the shim between the TO bearing race and pressure plate, nor do any of the 4Ts. It's only listed for the 2Ts as item #32 in the parts lists.
    #25
  6. lineaway

    lineaway Long timer

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    Oct 1, 2011
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    This thread is about a proper trials engine. If you watched the initial video.
    #26
  7. tacrac

    tacrac Adventurer

    Joined:
    Sep 20, 2013
    Oddometer:
    35
    I recently also added 2 of the KTM shims that Lineway also has done. At the same time I also changed from Motul to MTL 75 oil.
    From cold start at 50 deg F had absolutely no clutch drag. Lineway like yourself I have also done some clutch finger damage and would be very interested if you find lighter springs that work.
    #27
    Nobade likes this.
  8. Ymirtrials

    Ymirtrials Long timer Supporter

    Joined:
    Jan 12, 2012
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    1,345
    Location:
    Ymir BC Canada
    :tough
    #28
  9. tightwoods

    tightwoods Didn't need that dab...

    Joined:
    May 16, 2007
    Oddometer:
    23
    Location:
    PA
    OUCH!!!!!!! If it's a proper trials engine then why does the owner have to add shims that should have been done at the factory? I guess Ray Peters never got the memo.
    #29
    Junglejeff1 likes this.
  10. lineaway

    lineaway Long timer

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    Why are you screwing up this thread when the 4 stroke has no drag.
    By the way Ray has been lucky to ride basically the same bike for 14 years and he rides it well. We have been lucky that he has kept riding, instead of moving on to other sports.
    But a 2 stroke motor is way better for trials as the number of them made over the last 55 years is proof enough.
    MX would still be on 2 strokes if it was not for the green movement. Cams, rockers and a tottaly anvil for a motor is counter productive. Let alone cost of a rebuild.
    #30
    Nobade, slicktop and Norman Foley like this.
  11. Nobade

    Nobade Keep on keepin' on...

    Joined:
    May 30, 2012
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    1,477
    Location:
    Albuquerque, NM
    I just did this mod, with two of the .25mm shims. It really changes the engagement point so I had to adjust the clutch lever, but it works great. I've never been able to get to neutral with the engine running and now I can. It's going to take a bit of getting used to no drag but I think I'm going to like it. Thanks for the tip!
    #31
    wheelieman14 and jonnyc21 like this.
  12. Cascao

    Cascao Been here awhile

    Joined:
    Apr 4, 2018
    Oddometer:
    196
    Location:
    Brazil
    Can this be done in a sherco 2015???
    #32
  13. lineaway

    lineaway Long timer

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    The Beta has suffered clutch drag forever. The last Sherco we had was a 2012. The Sherco did not suffer as much, though it is a similar design. Being a 2015, I would make sure the master cylinder was working correctly first. Luckily our 2012 had AJP on it still. But Sherco for the most part from 2010 on had quite a few crappy hydraulics that came stock. The Bractech can be hit or miss on quality.
    #33
  14. Nobade

    Nobade Keep on keepin' on...

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    Albuquerque, NM
    I went for a real ride today and the clutch is slipping in 5th gear. Guess I'll take out one of the spacers and see how that works. It sure shifts a lot nicer now.
    #34
  15. lineaway

    lineaway Long timer

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    Yes, you can easily go too far. I guess that is why the Factory does not help us poor weekend warriors. :thumbup
    #35
    Nobade likes this.
  16. NZRalphy

    NZRalphy I'm not half as good as I think I thought I was

    Joined:
    May 14, 2011
    Oddometer:
    1,246
    Location:
    South of the North, NZ
    Well that looks easier than what I have been doing.

    .....for years I have been taking a new clutch plate and file away the fibre plate groves (just the groves) so the alloy shines through. So you are left with a nice clean square puck of fibre.

    There are, what, 7 plates, both sides, and 20 groves per side. It is hours of work with a rat file. It makes the clutch bite hard, holds oil so it releases cleanly, and has a great progression.

    I guess these are useful, but dam if this is an awesome adjustment. I like it.
    #36
  17. Wingboy

    Wingboy Been here awhile

    Joined:
    Sep 11, 2008
    Oddometer:
    602
    Location:
    Waterloo Ontario
    A slice of an old inner tube. I store my trialers this way. No stuck plates.

    Attached Files:

    #37
    joe cool and Junglejeff1 like this.
  18. lineaway

    lineaway Long timer

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    Here I thought your problem was clutch drag!
    #38
  19. snevil

    snevil n00b

    Joined:
    Jul 28, 2014
    Oddometer:
    2
    Thanks for posting this. I tried it on my 1996 Beta Techno 250 and it worked great. I can now find neutral or shift gears at a stop. After doing the clutch plate clean up posted on TrialsCentral the cold clutch plate sticking was fixed but my clutch dragged so much that it would move the bike forward even with the clutch pulled in and was impossible to find neutral at a stop.

    I used two of these 0.005" thick shims I ordered from McMaster-Carr:
    18-8 Stainless Steel Shims for Shortening 16mm Diameter Screw Shoulders, 0.005" Thick
    Delivers Tuesday, $6.45 per pack of 5, Part number 91437A555

    It turns out that two of these shims are 0.010" or 0.254mm thick and in the video it looks like they tried 0.10mm (not enough), then 0.30mm (apparently too much, although unfortunately I don't understand Japanese) and then settled on 0.20mm thick, so two of these McMaster-Carr shims are very close (0.254mm).

    While I had the clutch cover off I added two 1/4" washers on top of the clutch hub posts under each of the 6 clutch spring bolt washers to reduce the preload on the springs and make the clutch easier to actuate and more progressive. Two of these washers stacked up reduces the preload on each spring by 3mm which is the same distance as the nice machined clutch spring spacers discussed in the Beta Clutch thread on TrialsCentral.
    I used two washers, each 1.5mm thick that I ordered from McMaster-Carr:
    18-8 Stainless Steel Mil. Spec. Washer Passivated, 1/4" Screw Size, NAS 1149-C0463R
    Delivers Tuesday, $7.08 per pack of 100, Part number 98017A660

    It took me about an hour last night to make these changes and give the bike a test ride. When I came back inside my wife commented, surely you can't be done already?
    #39
  20. Wingboy

    Wingboy Been here awhile

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    Sep 11, 2008
    Oddometer:
    602
    Location:
    Waterloo Ontario
    Any feedback for us since you took one of the shims out? I have a 2020 Evo 200 with zero hours on it other than messing around in the driveway. Picked up my shims today.
    #40