Clutch Reassembling clutch - cover with clutch arm won't attach

Discussion in 'Transmission / Drivetrain' started by cloud_2901, Aug 1, 2011.

  1. cloud_2901

    cloud_2901 Member

    Hi all, attempted to search for answers to this with no luck, I'm just trying to finish off putting my 66cc 2 stroke Zbox back together after replacing bearings / gaskets / seals on it, but the cover over the drive sprocket with the clutch arm in it will not fit on so that I can get the screws in.

    Just wondering if anyone can enlighten me on whether it's the clutch spring preload that's set wrong (I didn't touch it so I wouldn't think so, but does it let off when you crack the case or something?) or whether there's another trick to getting it on. I still have all the bits, pin and ball well greased, so it's not a parts-missing deal, it just seems that something's not quite right, and I really don't want to take it all apart again to dig the spring out, so I'm really hoping someone can tell me it isn't that. Do I need to put the clutch plate on first before putting that on? My first-year mechanics teacher said that should usually go on last, me, I've no clue.

    Any more help from you guys would be great, as I also don't want to break it tomorrow by forcing something that shouldn't be forced, etc.

  2. Al.Fisherman

    Al.Fisherman Active Member

    I assume that when you got your engine the cover was installed and you took it off. Remove the bucking bar, don't loose the ball bearing it behind it, and see if the cover will go on.

    Here is a picture of the correct position that clutch arm will be when you have it wrong?
    Last edited: Aug 1, 2011
  3. cloud_2901

    cloud_2901 Member

    No Al, as I tried to say, I do know the correct way it's supposed to go, just that when I try to put the black cover on yours, on, some screws will not line up, about 10mm gap for the bottom single screw, with the other two sitting against the case, something just seems to not be working, and I really don't know why...

    Could the clutch cable guide thingy (stock one, haven't put a fancy roller thingy on - yet) be getting in the way of the clutch spring or something?

    When I try to put the cover on, it's hard up against the bucking bar, wobbles upwards / downwards due to being too far away from the case, and needs a LOT of force to push the bar in, so much that I don't want to try, to compress the spring and get it on (I assume that's how it's done, never put one back together before)

    Is this normal?
  4. Al.Fisherman

    Al.Fisherman Active Member

    Go into the clutch itself, remove the cover, remove the star machine screw and back the star nut so it's loose, then see if the cover goes over the bucking bar. Remove the "clutch thingy" (LOL) and back off the vertical bar, it just might be bound up on the clutch shaft. You never did answer my question....was it put together correctly, and you can't get it back on? Can you install it without the bucking bar installed?

    Back this out... at the tip of the arrow marked "FROM"?

    Modwocarb.jpg Mods/th_Modwocarb.jpg

    That screw sits right over the clutch shaft, and can bind it if it's too tight. Squirt some (small amount) of light grease while you are there.
    Last edited: Aug 1, 2011
  5. cloud_2901

    cloud_2901 Member

    At the moment my clutch plate is not on, should that be attached before trying to put the cover over the drive sprocket on? My teacher seemed to think they go on last in clutch setups, but he's worked on real motorbikes, not these...

    How would installing it without the bucking bar help? Then I'd have no clutch? Or would that tell you something important if I could / couldn't. I'm fairly sure it will though, the only thing holding it back is the bucking bar being there, and the force needed to push the spring. . I hope you're right and it's just bound up from the cable-guider thingymadoodad, have to attack it again in a couple of hours.
  6. Al.Fisherman

    Al.Fisherman Active Member

    Installing the clutch cover (on the left) without the bucking bar will tell me something...that the cover will in fact fit. You said it wouldn't. After you see that it WILL fit, remove it and continue. Next, install the clutch cover (right side) but before you install the left cover, remove the cable adjuster post. Now install the3 bucking bar and ball...ball going in first.

    Use this when you are referring to the engine parts. Get to know your engine.....
    Last edited: Aug 1, 2011
  7. cloud_2901

    cloud_2901 Member

    I have two of the bolts that attach the drive sprocket cover ( can't see a name for that on the diagrams you've helpfuly supplied) screwed in almost all the way, and the clutch works when I manually move the camshaft.

    Can I simply shorten the bucking bar and go from there? I know the cover will screw in properly if the bucking bar is a bit shorter, but not sure how it would affect operation. My bucking bar is made of a bit stronger metal than the camshaft, so it won't wear itself away after cutting it, just wondering if that's an acceptable fix or if something else will screw up after I've done it.
  8. motorpsycho

    motorpsycho Active Member

    Are you sure that you have the clutch arm inserted into the cover right? is the clutch arm all the way down into the cover as far as it will go?

    the clutch arm has a flat spot in it, that will go against the pin for the clutch. If the clutch arm is in the wrong position, the flat spot will not be against the pin, the round part will be. If the round part of the clutch arm is against the pin, the side cover won't go back on.
    Just a thought
    Last edited: Aug 1, 2011
  9. Al.Fisherman

    Al.Fisherman Active Member

    Umm first make sure that there is ONLY one ball bearing in the shaft (use a magnet and flashlight if needed. It wouldn't surprise me if 2 balls were installed.. No problem shortening the bucking bar, as you can make another one from a 5/16" drill bit. How far does the bucking bar stick out of the shaft, measure it, don't gestimate.

    You haven't answered my question...Was the cover installed properly before you took it off???
    Last edited: Aug 1, 2011
  10. cloud_2901

    cloud_2901 Member

    I sorted it out, and Al / motorpsycho it wasn't that I didn't know how it was supposed to go, or that the cover didn't fit, it's just I was doing it backwards. Clutch arm (camshaft on that labeled diagram Al has linked to) was definitely in the right way, all the way down, with the flat spot facing the bucking bar, so that it could actuate the clutch when pulled.

    I attached the clutch cover and set the flower nut in about 10-12 turns, and it seemed to drag the spring across (I also removed the clutch cable guide [screw base for brake line as it's labeled in diagrams] don't know if that affected anything but I was able to secure the drive sprocket cover on, in the right place, after just setting up my clutch and tightening it up.

    Thanks for the help anyway guys, was your suggestions that got me on the right track Al, and those diagrams are going to be extremely useful, thank you very much for them.

    Hoping to go get the thing back on my bike now! Only got to work out how to attach my new exhaust clamp rear mount bracket, and I'm set! Was just that one major setback when I went to reassemble the whole clutch / other side.
  11. Al.Fisherman

    Al.Fisherman Active Member

  12. cloud_2901

    cloud_2901 Member

    :grin5: :grin5: :grin5:

    Fixed it up now, running just fine.

    Had a hilarious moment after leaving TAFE, where I'm doing a mechanics course, left and made it about 200m up the street then bogged to a halt, thought maybe once the clutch got hot it started to slip or something, went back thinking I needed to open the side and retighten the flower nut, and one of my classmates reached past me as I was going for a screwdriver, to turn the fuel tap on.


    But I'm glad I made it work again, only other 2 stroke I've rebuilt was a Victa lawnmower we had to do for the course, and I didn't take the crankcase apart on that.

    Thanks again for the help, next project is a tuned expansion chamber!

    Is SBP the go for that or does anywhere offer a better pipe?
  13. remichi

    remichi New Member

    I have the same problem with the drive gear cover not wanting to to fit. The bucking bar is sticking out too much.

    Strange thing is that it was working before....

    I installed the engine today, drive gear cover was still ok, tried to start the engine which wouldn't start, then took the drive gear cover off and now it won't go back on.

    Also how do you remove the ballbearing behind the bucking bar?
  14. Alexmeow

    Alexmeow Member

    I'm having this same problem the clutch was working fine there was a stripped screw and I had to break the cover off to get inside no change but then suddenly it just wouldn't fit in anymore and I can't get the ball bearing out to check if there's 2 or 1 does anyone know any tricks to get it out?
  15. HeadSmess

    HeadSmess Well-Known Member

    lazarus thread...

    zombie thread!

    mmmm, braaaaaaains.

    PS, check the dates on last posts ;)

    um, tip it on its side, wack it a bit.

    spray some WD40 or something in the hole.

    use compressed air...
  16. HouseOfEl

    HouseOfEl Member

    Damn, I'm going to resurrect this thread one more time... must have 9 lives.
    My bike seems to be ready to fire up for the first time except for the fact that when my camshaft is out, my wheel spins freely, when in, it locks up. (So basically the reverse of what it should do). I can't figure out why. It was working fine until 1) I tightened the cable too tight and tried to pull it. Do you think something was shifted out of alignment?
  17. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    Clutch arm, and actuator cam pushes the bucking bar et al over to the RIGHT.. That's how it separates the clutch plate from the clutch pads. The only thing that is further right than the clutch plate is the clutch COVER. Remove it and see what happens. Maybe the plate was hitting it? IE maybe the clutch seperation is way more than necessary, it only needs to separate a bit. Hold lever in and tighten the flower nut down further, all the way and then back it off until there's only a small amount of separation.
    Also as Al Fisherman says in this thread.. Something could be hitting the cable mount post (thing in the centre that your cable outer ends at) so take it out and operate the clutch arm by hand just to test. If that works you can put it back in but with it's locking nut moved down a bit so it doesn't go in as far this time.

    Doesn't explain why it was fine before. Is the tiny flower nut locking screw missing?

    Let us know how it goes.
    Last edited: May 9, 2016
  18. HouseOfEl

    HouseOfEl Member

    Thanks for the speedy response, I think I literally may have shifted the clutch arm and actuator somehow. Now that I've taken the cover off and simply put it back on (I didn't even really adjust anything) it seems to be out to engage, in to disengage. But I really may have shifted something because I have to push the clutch arm ALLLLLL the way in to get to disengage. Neighbor who just happened with working on his moped says a simple fix is just cutting the spring in half and taking out the new slack that will give me. Also he says my tensioner isn't giving the bottom half of my chain any play and it's too tight. Last but not least, we saw the chain was scoring/making a groove on the inside of the clutch cover.
    Tomorrow I will cut spring and remove slack that leaves. Readjust tensioner. And IF the new slack in chain doesn't fix grinding problem I will groove out the spot where the chain is hitting.
  19. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    Dont cut your spring. You can't glue it back together again if it turns out to not be the fix.
    There's no rush.
    Wait for more replies and have a look at things and a play but just don't do anything you can't undo. It worked okay before.
    Which spring are we talking about anyway? The one on the bare clutch cable that sits in between the cable stop and the actuator arm? That can be removed but just to make pulling the lever on handlebars easier.
    I'm sure there's something else going on.
  20. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    The clutch arm is supposed to be out when the clutch is engaged (to drive), pulled in towards centre to disengage (when freewheeling, or pedalling the bike)

    Having to pull so far to disengage is wrong..
    Is the cam damaged? That's the vertical pin with the flat side, operated by the arm.
    Is the bucking bar damaged or not protruding from the shaft as much as it should/ used to? It should be about 6mm 1/4" if memory serves me correctly..