Tonti Clutch Drags like crazy and i think i know why - FIXED!!!

[kfz]

Help, I keep inspecting and re-assembling my Mille GT clutch but it just drags like mad.  Bad enough to stop selection of gear.  Ive inspected all the components but can find nothing wrong.  It feels all wrong at the lever and doesnt have a progressive pull like you would expect.  Its very heavy and does not have a progressively harder feel feel you would expect as springs compress.  its also doesnt make the distinctive ring - a -ding when its pulled in its not disengaging!!

Really at a loss with this.  The clutch was disassembled because of the dragging,  Where i replaced the frictions,  Pushrod and springs.  Ive done loads of clutches and they just work.  But this one is driving me mad.


• New springs,  Frictions (in fact 2 set of frictions), thrust bearing, pushrod
• Intermediate plate is not warped and shows dead flat on a straight edge
• Pushrod measures 245mm.  springs measure 29-30mm
• Springs defnetly located correctly. Dimple positioned right see pic
• Plate shoulders to rear
• clutch centre tool used
• Cup located
• I did the main seal at the same time so removed the flywheel,  not sure if this relevent?
• The ring gear shows slighly uneven wear,  slight burnishing (may the drag) to the outer edge, see pic
• Intermediatte plate is not warped and shows dead flat on a straight edge

[/list]

[kfz]

The intermediatte plate looks dead flat to me.  Ive seen warped ones and this isnt it.....

[guzzisteve]

Make sure the cup that rod fit's in is not too deep of a hole. A friend of mine just had one of these keep wearing down. Get measurement of new and compare.

[tris]

Not wanting to be an A$$, but have you checked the cable (freeness and routing), bar lever,  the actuating lever pivot points?

You probably have checked but you didn't say

Also, I had a problem with an aftermarket lever not doing what it should do so might be worth a check if that applies

[Antietam Classic Cycle]

What friction plates have you used? If SD-TEC, they are a bit thicker than the original and will require some extra length be added to the throw-out assembly to disengage correctly.

Is the outer body of the throw-out assembly flush or nearly so with the rear cover of the transmission? If it's recessed into the cover more than a millimeter, there can be clutch issues.

When it's recessed too far, I add an extra thrust washer from an old throw-out bearing, sometimes two if necessary.

 

[kfz]

Make sure the cup that rod fit's in is not too deep of a hole. A friend of mine just had one of these keep wearing down. Get measurement of new and compare.

Good call,  i'll check that, sure i have spare somewhere.....

Kev

[kfz]

Not wanting to be an A$$, but have you checked the cable (freeness and routing), bar lever,  the actuating lever pivot points?

You probably have checked but you didn't say

Also, I had a problem with an aftermarket lever not doing what it should do so might be worth a check if that applies

Nah,  its not that.  Ive tried all kinds on adjustments a all points, Tried a new cable.  To get the clutch remotely disengage i've no free play , something is very wrong.

[kfz]

What friction plates have you used? If SD-TEC, they are a bit thicker than the original and will require some extra length be added to the throw-out assembly to disengage correctly.

Is the outer body of the throw-out assembly flush or nearly so with the rear cover of the transmission? If it's recessed into the cover more than a millimeter, there can be clutch issues.

When it's recessed too far, I add an extra thrust washer from an old throw-out bearing, sometimes two if necessary.

Sureflex.  But tried another set as well and they are exctly the same.

The plunger was well recessed so i popped a 3mm Ball in there.  it brought the plunger back up fluch with the case but the clutch was actually worse.

[lucian]

How do the spline grooves in the flywheel look ? Are they notched at all?

[tris]

Nah,  its not that.  Ive tried all kinds on adjustments a all points, Tried a new cable.  To get the clutch remotely disengage I've no free play , something is very wrong.

I thought as much
No one with any sense gets that far into an engine without a good degree of tackling the basics first ..... though I have seen it on threads!

Good luck though and I shall watch this thread with interest.
You never know, I might end up in the same predicament somewhere down the line

[Antietam Classic Cycle]

I'd only use Sureflex plates if they were the only ones available. Tried them once and within 10k miles they had notched the hub. Were always grabby with on/off engagement. SD-TEC plates are far better.

[Wayne Orwig]

I'd only use Sureflex plates if they were the only ones available. Tried them once and within 10k miles they had notched the hub. Were always grabby with on/off engagement. SD-TEC plates are far better.

Same here. The Sureflex were very grabby.
The SD-TEC work great, but I suspect the machining of the grooves left the surface uneven, so they drag a bit. From then on, I sanded the surface a bit to even them up and no more issues.

[bigbikerrick]

I agree as well regarding the sureflex plates. They are very grabby, and even though new, I replaced them right away with sd tech. on my 73 eldorado.
Rick D.

[Tom H]

"Plate shoulders to rear"

You mean the friction plates, and to the rear means the rear of the bike? Not facing in toward the flywheel correct?

Another thought, is you trans clutch lever bottoming out on the trans case when you pull the hand lever?

Tom

[pressureangle]

From a diagnostic standpoint, it would seem that whatever you were trying to correct in the first place still exists. Look to the pieces you did not change- pushrod, etc. as stated some part may be worn and length is an issue. When did the first problem begin? Was a new transmission housing installed? New input spline, mismanufactured? Flywheel on backwards? If you remove everything you've put new, you're left with what's the problem...somewhere .

[kfz]

"Plate shoulders to rear"

You mean the friction plates, and to the rear means the rear of the bike? Not facing in toward the flywheel correct?

Another thought, is you trans clutch lever bottoming out on the trans case when you pull the hand lever?

Tom

Nope , i dont think so....  But its disembled now.

[kfz]

How do the spline grooves in the flywheel look ? Are they notched at all?

like new. and clean. 

clutch hub is perfect as well

[Tom H]

Just to be clear. The friction plates have a raised area where the spline is rivet to in the center on one side and the other side if flat.

That raised side should face out while installing the friction plates. When the clutch assy is together, you will see the raised center.

If you install them with the raised in toward the engine, IIRR it can make it so the clutch will not open when you pull the hand lever.

Added a pic. The one on the left is how it would look with the clutch assembled.




Tom

[Huzo]

Do you have a visible actuating arm that compresses the pushrod ?
If so, what happens if you mechanically depress that arm fully ?
If doing that frees the clutch, then the components upstream are not providing the required travel..
If it does not free the clutch, the it’s nothing upstream of the actuating arm.
Can you be convinced that the plate is not twisting on the splines and therefore still dragging on one part of the perimeter ?

[kfz]

Do you have a visible actuating arm that compresses the pushrod ?
If so, what happens if you mechanically depress that arm fully ?
If doing that frees the clutch, then the components upstream are not providing the required travel..
If it does not free the clutch, the it’s nothing upstream of the actuating arm.
Can you be convinced that the plate is not twisting on the splines and therefore still dragging on one part of the perimeter ?

Hi Tom,  Yes.  This was my second tjough after the warped intermediate,  but no  the plates are fitted correctly pointing aft (rearward).

Kev

[kfz]

Do you have a visible actuating arm that compresses the pushrod ?
If so, what happens if you mechanically depress that arm fully ?
If doing that frees the clutch, then the components upstream are not providing the required travel..
If it does not free the clutch, the it’s nothing upstream of the actuating arm.
Can you be convinced that the plate is not twisting on the splines and therefore still dragging on one part of the perimeter ?

Yes.
The Clutch still drags

The fraiction plates are new.  Ive tried another new set i had in stock.  The plates are good fit (Deep splined hub).

[Huzo]

Yes.
The Clutch still drags

The fraiction plates are new.  Ive tried another new set i had in stock.  The plates are good fit (Deep splined hub).

Ok so now you know that any investigation into levers, cables etc…Is a time wasting exercise for you.

[kfz]

Ok so now you know that any investigation into levers, cables etc…Is a time wasting exercise for you.

Huzo,

yep,  i sorta knew that, hence stripping the bike down and pulling out the clutch in the vain hope I coild find something amiss.

My suspicions lie with the pushrod and cup at the moment.

[Antietam Classic Cycle]

Huzo,

yep,  i sorta knew that, hence stripping the bike down and pulling out the clutch in the vain hope I coild find something amiss.

My suspicions lie with the pushrod and cup at the moment.

If the pushrod is the correct length, then it isn't that. The hole in the center of the "cup"/thrust piece should be around 6.5 mm deep. It would have to be much deeper to cause the issues you're having.

[acogoff]

    I would suspect the splines of your clutch plates, although they may be near new, are not "splinning" well in their marriage to the center hub of the transmission.
A burr on a part or some slight variations in machining is all it would take to cause a bind. A little work with a die grinder or needle file may be all it would take.

[kfz]

    I would suspect the splines of your clutch plates, although they may be near new, are not "splinning" well in their marriage to the center hub of the transmission.
A burr on a part or some slight variations in machining is all it would take to cause a bind. A little work with a die grinder or needle file may be all it would take.

Happy to look into any thing.  I'll check it out.

KEv

[Alfetta]

never been into one yet..  but these kind of issues are fun for me to think through.
so the following is probably crap, but I'm wondering if it is possible that the entire clutch / flywheel may not be in the correct position.
not fully seated or missing shim ???

I'm also wondering if you have measured over the friction material of the old clutch vs. the new clutch.
if the variation is large, it may point to an incorrect friction thickness on the new part...

OK...  Ill shut up now

[jacksonracingcomau]

Really surprising that no one else has said it but here goes.

As with any multiplate clutch, the only part that truly ensures clutch disengages drive is the pressure plate. It must travel freely and squarely a few thou and plates will spin.
Even though I hate Surflex plates , they only change friction point when hot imhe, from cold they’re as expected.
So , if pressure plate teeth/flywheel internal teeth are not the issue we are only left with 8 springs, each must give same pressure for plate to travel squarely when pushed from centre.
Assemble clutch with engine nose down (in car tyre), making sure all springs are perfect and correctly located into recesses BEFORE fitting centering tool. When assembled and tool removed fit gearbox while still nose down, in gear so output shaft does not turn.
Adjust pushrod and then press lightly on clutch operating arm, minimal pressure will allow output shaft to spin (clutch releases ).

Assemble in bike , run and enjoy

I have found springs wonky and distorted from being assembled with engine upright, even though dots are lined up, one spring can fall out of recess causing issue. That spring is now u/s —it will not bend back

If in any doubt whatsoever, buy 8 new springs

[John A]

Do you mean the clutch doesn’t release when you pull the lever? If that’s what you’re saying,  what I do is space the lever farther from the handle bar to give it more throw.  Works especially well on ram clutches so it will release as well as have freeplay. I have made my own spacers but someone here posted a link for them so I’ll post that if I find it.

Found it! https://www.righteousstuntmetal.com/products/rsc-perch-spacer

I initially made one trying to get a Ram clutch to release while giving it free play. I liked it well enough that I use it on  a regular clutch. I went to an adjustable lever for more fine tuning. It may help.

[Tom H]

I'm sure you have double checked that you got the conical push rod seals out before installing new ones or the O ring setup.

Tom