Jump to content

Greenalg

74 Ty250 clutch problems

Recommended Posts

The mechanism that pushes the pushrod to disenguage the clutch plates isnt working right and drops a bit.  Seems like it is not pushing the pushrod, there is no resistance against it, and it doesn’t return to neutral positions. Do I have to split the cases to get to it to repair it? Any thoughts on what it might be?

Share this post


Link to post
Share on other sites
 

Probably need a bit of history about the bike to someone to work out what has happened here. It could be lots of things

Share this post


Link to post
Share on other sites
 

So the clutch was working fine oh my son moved it and it fell over. That broke the clutch perch. I posted I have removed and look at the clutch basket and it appears all is OK on that side. I’ve removed the adjustment screw/bolt and removed the mechanism that pushes the pushrod. Both of those seem to be OK  it’s just that the pushrod doesn’t engage with the mechanism until the mechanism is partially trend and therefore it doesn’t push the pushrod open enough. What is the clearance of the open clutch basket? It seems like its only 1/8 inch. 

Share this post


Link to post
Share on other sites
 

1/8 inch is probably even more than standard. I've never bothered measuring it to know exactly.

There is normally slack in the rotation of the camshaft before it touches the pushrod.

If the clutch was working OK until the lever perch broke, why do you now think something has gone wrong in the mechanism?

Share this post


Link to post
Share on other sites
 

What kind of ''resistance '' do you have when you pull the perche.

Guy

Share this post


Link to post
Share on other sites
 

None for 80% of the travel.  Then normal. Looked at the mechanism underneath and it would slip in and out and rotate 80% before enguaging the pushrod. I took that apart and put it back together and adjusted the adjustment screw/nut to hold it in place. 

Share this post


Link to post
Share on other sites
 

I reckon I know what's happened. You said that you took out the actuator camshaft. The only way to do that is if you remove the clutch pressure plate and let the pushrod move to the right far enough for the camshaft to come out. I reckon that while you had the pressure plate off, the mushroom part of the pushrod slid out and so did the ball bearing behind it, without you noticing the ball bearing.

That would explain the symptoms you have now with it reassembled

Edited by feetupfun
  • Like 4

Share this post


Link to post
Share on other sites
 

If I have the pressure plate and the actuator at the other end both removed should be ball bearing and the shaft both be removable?  

Share this post


Link to post
Share on other sites
 
 
 
On 5/17/2020 at 8:17 AM, Greenalg said:

The mechanism that pushes the pushrod to disenguage the clutch plates isnt working right and drops a bit.  Seems like it is not pushing the pushrod, there is no resistance against it, and it doesn’t return to neutral positions. Do I have to split the cases to get to it to repair it? Any thoughts on what it might be?

There is an external spring under the engine cases that returns the control arm to the ready position. I had trouble with that once before and was able to remove the arm and replace it and the seal without splitting the cases.  But you'll want to drain the transmission oil before you pull out the control arm if you want to work on it.  Therre is also an adjuster bolt on the side of the case that sets the end play and that controls how much throw is transferred to the clutch plates when you squeeze the clutch lever.  But don't take that adjuster bolt out. I'm not sure the internal parts (a ball bearing and a spring) would stay in place if that adjuster bolt was completely removed.  You want to look over the repair manual real close before you do too much tinkering.

Share this post


Link to post
Share on other sites
 
On 5/17/2020 at 8:17 AM, Greenalg said:

The mechanism that pushes the pushrod to disenguage the clutch plates isnt working right and drops a bit.  Seems like it is not pushing the pushrod, there is no resistance against it, and it doesn’t return to neutral positions. Do I have to split the cases to get to it to repair it? Any thoughts on what it might be?

I have my engine and gearbox ALL APART and I can take pictures for you. I'm no experrt on clutches, but it should not be that hard to figure out.

I also have a good parts manual and exploded views of the parts and how they fit together.  Do you have any reference documents? If not. there are free diagrams online at Partzilla and many others showing the exploded views.

Is there any chance that you are missing the ball bearing out of the assembly?  I think it rides on the inside end of the pushrod.  Also the pushrod is rounded on one end and flat on the other end (at least mine is) and those details are not visible in the diagrams.  So it would be possible to get the pushrod in backwards and or forget the ball bearing that rides on the inside end of the pushrod. 

There is also a spring outside the cases that returns the "cam" rod back to the starting position. If that spring was missing or broken, it would keep the whole mechanism from working.

 

Share this post


Link to post
Share on other sites
 
On 5/24/2020 at 7:50 AM, Greenalg said:

The ball bearing is there. How do i remove clutch pushrod?

On the ty250 A like mine, the main pushrod cannot be removed without splitting the cases.  Reason being- the hole you can see is smaller than the diameter of the pushrod.  The other end where the clutch actuator cam is located has an opening large enough for the main pushrod to be assembled into. but the end you can see with just the clutch cover off is too small, and will only accomodate the smaller "top-hat" pushrod diameter and the ball bearing.

I took a few pictures, but I don't know how to upload them on here.

 

It's interesting to know that without the ball bearing inserted between the two pushrods, the ends of the pushrods will only come flush with the ends of the gearshaft that they ride in. so if that ball is missing, you won't be able to release the clutch at all and the back tension on the clutch cable would be slack which is the symptom you mention.

 

Since the ball is magnetic,  and if you have a magnetized nail or similar, you can probe and see if the ball is really present. It will come right out if it is in there.  The hole is big enough for the ball- no problem, just not the main pushrod itself.

Your problem is fairly simple if you don't really have to remove the main pushrod.  all you have to do is fill up the distance between the inside of the clutch pressure plate and the cam actuator face.

And if the cam actuator is in it's relaxed position, the length needed to bridge the distance will be at a maximum.

 

You should also be able to check for the presence of the parts by measuring the depth of the hole.  If the hole is just slightly deeper than the length of the small pushrod, the ball is missing. Pulling in the clutch lever will have no effect on the pushrod position.  If the ball is present, the small pushrod will protrude out the end of the shaft about 1/8-3/16" and move with the movement of the clutch cam actuator rotation.

That is about it. There is no other scenario in which the pressure plate won't move if all the parts are present and the clutch main nut is tight.

 

 

Share this post


Link to post
Share on other sites
 

One shot that might help. If the ball bearing is missing, the left end would be flush, and on the right end, the "tophat" would bottom out in the hole.  If the ball is present, then the positions you see here would happen because of the extra stack length of the parts.

IMG_4691.JPG

  • Like 1

Share this post


Link to post
Share on other sites
 

One more possibility- I found this out today- playing with my own clutch assembly - The pressure plate (item 7) can be mis- aligned over the 6 female mounting points in the clutch boss.

The 6 screws and springs will still tighten up, but the pressure plate on top is not seated all the way down.  This would put the pressure plate too far away from the push rod end,  and put slack in the cable.  So if you  back off the 6 screws in the pressure plate and wiggle/spin it left and right, you might feel it seat properly.  That will get the top plate closer to the push rod and take more slack out of the cable.   One note - the steel clutch plates all have a special shape on one edge.  These are supposed to be clocked around the clutch basket about every 60 degrees to keep the clutch balanced.  

Share this post


Link to post
Share on other sites
 

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...