clutch issue

FurryOnTheInside

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Sep 23, 2013
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the flower nut can be threaded on a few turns.

here is a label of what I'm calling the parts (stolen from a bikeberry youtube video) so we're all on the same page.
View attachment 85418

here is the clutch side with flower nut threads exposed


sprocket side



I kind of see what you are saying about tightening the flower nut because it *should* compress the spring and pull the push pin towards the clutch side, right? But with that said, I've tried to push the bucking bar and ball by hand, didn't work. inserted very long allen bolt and tried pushing it that way. it won't budge. are these springs inside that stiff?
They (it, only one) is strong enough to prevent the clutch from slipping under power. The clutch pressure is adjustable by the preload nut.
(The main spring preload nut is shown on Manic Mechanic's diagram. It is immediately to the left of the right hand bearing.)

Just like working on a shock absorber you need to either compress the spring or slacken the preload nut to remove the preload from spring.
Put a chain onto the sprocket. Remove the clutch cable stop and place a flat head screwdriver into a slot in the preload nut and then pull the bottom of the chain to rotate the clutch shaft. This will loosen the preload nut.

Then hopefully you can place the bucking bar and ball into the shaft and put the engine down on the table and press the engine down onto the table, and the threads for your flower nut will protrude enough to screw on. Actually I'm sure you'll have to place something on the table to press the bucking bar in but the message was about the preload.
 


mangosmoothie

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Right now when I try pushing the bucking bar against the table it will not budge. I would think the clutch spring is not that stiff and I should get movement of some kind
 

mangosmoothie

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I've tried inserting the ball and bucking bar and pushing it against a table. It won't budge. I don't weigh a whole lot, but there was 130 lbs of force leaning against it.

I find it hard to believe the preload would suddenly off, since it worked fine before and I haven't touched it. Someone else also said to put the sprocket cover on and turn the screws a bit at a time to force it on. This seems like a recipe to break the cover since I can't get it to budge.
 

mangosmoothie

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Does someone want this bottom end before I destroy it?

The clutch cover is so far out I can't even get the cover bolts started

Then I tried to pull the sprocket off so I could either split the cases or pound the clutch shaft out and the friggin puller stripped.

Why is this engine cursed :'(
 

FurryOnTheInside

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Someone else also said to put the sprocket cover on and turn the screws a bit at a time to force it on. This seems like a recipe to break the cover since I can't get it to budge
I reckon only risky if the main spring is still preloaded. I (only guessing, haven't done) guess that you could do it if there's no preload on the spring you're pushing against. I don't think anything broke but you disassembled with the the preload set as it came, as normal for bolting straight on and riding.
IMHO, if you have successfully relieved the preload but still can't press the bucking bar down on the work table, you should try using the cover bolts very carefully and evenly.
At this point when you are considering giving away the bottom end anyway there's little to lose?
I tried to pull the sprocket off so I could either split the cases or pound the clutch shaft out and the friggin puller stripped
I think that was the impact driver.. The sprocket needn't be forced onto the taper, just snug and with its woodruff key, and the nut can be secured with blue loctite and a normal wrench. But it's done now.. Do you have a gear puller with jaws narrow enough to get down around the sprocket?
puller.jpg
 

FurryOnTheInside

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I'm starting to wonder whether the impact driver pulled the shaft through (although I doubt that the sprocket can be pushed on far enough for that to happen.. But there isn't much taper so maybe..) :unsure:
 

mangosmoothie

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The impact is pretty weak at just 1/4" but you might be on to something. I vaguely remember needing to use a breaker bar for one of those big nuts, and I think it WAS the sprocket size. The impact couldn't do it, so if anything it just hammered the sprocket on further. No way to prove it, and it's already done :/

still doesn't explain why the push pin is absolutely seized. That should be moving regardless. I'm not crazy, right? Putting the ball and bucking bar in it, setting it so the bucking bar is on a table edge, and pushing the entire engine against the table on that side SHOULD cause the push pin to move outward, because that's how the regular clutch works. The push pin pushes the flower nut out, and the spring between the clutch disk and plate pushes the plate away when the flower nut comes out. So with 100 lbs of force against the bucking bar, the push pin SHOULD be actuating. And it just isn't.

A new puller is coming soon (thanks amazon) so I'll pop the bevel gear off first, then try the sprocket again. I do not have the little jaw puller things but I think the auto parts store will loan them. Or I can try pounding the shaft out towards the clutch side which should force the sprocket off. I'm beyond caring about this bottom end. This whole engine has been trouble since day 1.
 

mangosmoothie

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Ok got the cases split and the clutch shaft out. I don't know how much preload is too much but it seemed like there was a lot. After removing the spring, the push pin moves freely in the clutch shaft. I think there was just too much preload. if I tightened the flower nut further and further it may have worked. But now I can see nothing is broken.

Fred probably has a different amount of preload which allowed for easier reassembly.
 

kinsler33

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Jun 15, 2018
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I think it won't go together properly if the clutch plate has been removed. Try re-installing the clutch plate, screw the 'flower nut' in a bit, and then try fitting the clutch actuator stuff.

I'd also suggest that if the steel cam bar that pushes upon the 'bucking bar' has a rough finish (that is, the round bar which the cable-lever rotates) that you smooth off the rough finish with several grades of successively-finer emery cloth or other abrasive until it is pretty well polished. The reason is that this cam rides in rather crude bearings cast into the aluminum housing and if it is rough it will wear right through those bearings in short order. So sand it smooth, and smoother, and add some good sticky grease in its bearings when you put the clutch together.

If this is not done and the cam bar bearings wear out you'll find that you have to push the clutch lever farther and farther to get the clutch to release.

Also note that these bikes require some technique to start and to ride. Mine will not start unless the choke is completely closed and the carburetor is primed, but once it starts the choke must be opened immediately. I'm thinking of adding a spring and latch so that I can snap the choke wide open once the engine starts instead of feeling around for its little lever. Once the engine warms up you'll find that it's far less eager to stall when you engage the clutch.

Mark Kinsler
 
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