Clutch arm slipping?

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Farthom

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May 16, 2010
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This is going to be a bit of a tough problem to explain. I have a brand new engine now, and I am trying to get the clutch adjusted right. So far, each time I get the clutch adjusted, about 5 mins of riding I find the clutch stops working and the whole clutch cable/arm is loose and floppy. I would then proceed to slide the little clutch wire clip up (about a full cm each time) until it works again. This cycle has repeated itself enough times now that the clutch doesnt even begin to engage until the clutch arm is practically touching the clutch screw base (the thing that screws into the crankcase) If you were to think of the clock analogy where 12 oclock points to the right side gear cover, the clutch arm is completely loose (does not even begin to move the rod) until about 2 oclock. The last engine I had would engage the cluch at about 5 oclock. The first time I ran the engine it was at 5 oclock, and has slipped up to 2 oclock over the course of less than an hour. I've been poking around and messing with the clutch flower nut, but I am convinced that the problem isnt on the right side of the engine since it doesnt even move anythign on the right side until 2 oclock.

What on earth can be happening here? Its a brand new engine.

Matt
 
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Farthom

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May 16, 2010
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I'd like to toss up a few pictures to try and make this clearer. The first picture is the clutch which the clutch lever OUT. the clutch arm is reasonably loose in this position. The second picture is with the clutch handle pulled all the way in. Notice how it is nearly touching the post in the engine casing. In this position, the clutch half works. (catches a bit, too much to let the engine idle) So the bike is pretty much useless.

Here are things I have tried having searched the forums more:

- I tried messing with the flower nut on the other side. No adjustments make any difference. When I pull the clutch lever and watch the post on the right side, it doesn't move outwards very much. (Like half a mm, barely noticeable to the naked eye) I had another bike where the clutch would move outwards nearly a full cm.


- I tried replacing the entire clutch arm, and drive sprocket cover from a working bike. It made no difference.

- I notice the clutch pin (inside the drive sprocket) has a little divit in it. Is this normal, or is the internal ball bearing inside creating this. I will take apart another brand new engine to confirm whether this divit exists. What can I do to stop this from happening?
 

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Farthom

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May 16, 2010
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Sorry for a triple post, but I have one additional image to attach. The left is the pin from my engine (less than a day old) and the one on the right is from an engine that has never been installed. It is clear the creation of this divot is what is causing my clutch problems. Question is, what can I do about it? What can I do to prevent this same thing from happening to the other 4 of 5 engines I intend to build onto bikes?

Matt
 

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Al.Fisherman

Al.Fisherman

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Sep 9, 2009
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Two things need to be done. First remove the clutch arm from the cover bracket. This involves taking the cover off. With the cover in one hand turn the clutch arm till it will pop out. BEFORE you do this, make a mental note where you want the clutch arm. I like the arm to point parallel with the bike. Remove the nut on top of arm, and drive the clutch pivot out of the arm. Use a center punch and a vise if you have one. The pivot is splined. Set the arm on the pivot, not real hard, put arm into the cover and check the setting. If it like you like it, then remove and drive arm onto the shaft. A socket does well.

Second...do away with the valley point, there are a few things that you can do. One is a noodle, and another is a roller bracket that I sell and if able you can make for yourself.

Bucking bar......Noodle ...Clutch roller
 
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Al.Fisherman

Al.Fisherman

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Farthom said:
Sorry for a triple post, but I have one additional image to attach. The left is the pin from my engine (less than a day old) and the one on the right is from an engine that has never been installed. It is clear the creation of this divot is what is causing my clutch problems. Question is, what can I do about it? What can I do to prevent this same thing from happening to the other 4 of 5 engines I intend to build onto bikes?

Matt
Click to expand...
Cut a drill bit the same length, a 3/16" diameter if I reminder correctly and replace the ball bearing with a good grade steel ball. First photo above..the pin is called a bucking bar...one is stock, the other I made from a drill bit. Can you tell which one is what?
 
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Farthom

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May 16, 2010
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What about whatever rod is on the right side of the ball bearing. If I remove the "buckling bar" and ball bearing, then aim a flashlight down the shaft, I can see it also has a divot in it, perhaps more significant than the bucking bar. Somehow I think simply cutting a new bucking bar would only band-aid the problem, as the inner rod would continue to compress perhaps until it balloons outwards enough to become stuck in the shaft. Keep in mind, the above photos I took... this all happened in under 20 minutes of riding a brand new engine. This wear is happening at a much higher rate than normal. My old bike (1 year old) its bucking bar has no divot whatsoever, and you can't even tell it's been wedged up against a ball bearing. I somehow refuse to believe the stock buckling bar would be of such low quality the kit is unworkable from day one.

Could a lack of grease cause it to wear out this fast? I kinda just slapped the engine on and went for it. It does have grease, just some crappy looking yellow crud that came with it.
 
Al.Fisherman

Al.Fisherman

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Farthom said:
What about whatever rod is on the right side of the ball bearing. If I remove the "buckling bar" and ball bearing, then aim a flashlight down the shaft, I can see it also has a divot in it, perhaps more significant than the bucking bar. Somehow I think simply cutting a new bucking bar would only band-aid the problem, as the inner rod would continue to compress perhaps until it balloons outwards enough to become stuck in the shaft. Keep in mind, the above photos I took... this all happened in under 20 minutes of riding a brand new engine. This wear is happening at a much higher rate than normal. My old bike (1 year old) its bucking bar has no divot whatsoever, and you can't even tell it's been wedged up against a ball bearing. I somehow refuse to believe the stock buckling bar would be of such low quality the kit is unworkable from day one.

Could a lack of grease cause it to wear out this fast? I kinda just slapped the engine on and went for it. It does have grease, just some crappy looking yellow crud that came with it.
Click to expand...
A good quality ball bearing should take care of the clutch shaft. With using the drill bit in front of the bearing, I think all your problems will be solved...Grease the ball with a light grease. The bearing and bucking bat are cheap junk, more so then the clutch shaft.
 
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Farthom

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May 16, 2010
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I just installed a brand new bucking bar and bearing from another engine. (Never been used) The clutch arm situation has not improved. There is just too much wear on the clutch pin mandrel inside the clutch shaft. I looked down the shaft with a flashlight, its worked itself into a nearly perfect "cup" that the ball bearing sits in. Sure I could cut a bucking bar a bit longer from steel rod, but would this seems like it would only delay the same problem for yet another 20 mins of riding.
 
Al.Fisherman

Al.Fisherman

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What I would do if it's my engine is, slide the ball in then a shaft (like a drill bit) and cut overall length...then cut the length down as need be..to where you need it. I'd do this before I went into it.
 
2door

2door

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Sep 15, 2008
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Farthom,
Are you lubricating those parts? Cam, pin and ball bearing? If you can look in the hole in the sprocket and see anything besides grease, you're not lubricating those parts like they should be.
As for fabricating a new pin keep in mind that the length is critical. You can take Al's advice about making one but I'd use a 5/16" drill bit, not 3/16"...same for the ball bearing.
The ramp on the cam and the end of the pin that makes contact with it should not have any rough edges. I polish mine on a bench buffer to a chrome-like finish, lubricate all the moving parts with a good quality bearing grease and assemble.
Good luck.
Tom
 
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Farthom

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May 16, 2010
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As for the clutch pin mandrel, I'm thinking of cutting a small disk out of steel rod and sticking it in there. I REALLY do not want to have to take the engine apart after only a few hours. This should provide a flat surface for the ball bearing.
 
Al.Fisherman

Al.Fisherman

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Sep 9, 2009
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2door said:
Farthom,
Are you lubricating those parts? Cam, pin and ball bearing? If you can look in the hole in the sprocket and see anything besides grease, you're not lubricating those parts like they should be.
As for fabricating a new pin keep in mind that the length is critical. You can take Al's advice about making one but I'd use a 5/16" drill bit, not 3/16"...same for the ball bearing.
The ramp on the cam and the end of the pin that makes contact with it should not have any rough edges. I polish mine on a bench buffer to a chrome-like finish, lubricate all the moving parts with a good quality bearing grease and assemble.
Good luck.
Tom
Click to expand...
Wasn't sure about the diameter of the drill, but yea 5/16" sounds right...what ever the pin is, I wasn't sure which one at the keyboard. I made one almost 2 years ago, as a member needed one...made it and took a picture of it so it could be posted.
 
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rohmell

rohmell

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Jun 2, 2010
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If you're starting out at 5 o'clock and ending up at 2 o' clock, I think more likely the serrations in the clutch arm are not gripping the shaft with the cam on it, and it is slipping there.
 
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