Author Topic: total pressure plate lift  (Read 437 times)

Online coater87

  • Wise & Enlightened
  • *
  • Join Date: Jul 2008
  • Posts: 1166
  • Karma: 6
total pressure plate lift
« on: 19.06. 2019 01:18 »
 On my bike, I am getting about .070 thousandths (1.77 mm) of total pressure plate lift with everything adjusted for maximum lift.

 Is this close to what others have?

 It seems to me I should have more and I am starting to eyeball the cable in a bad way.

 This is a swing arm bike.

 Lee

 

Central Wisconsin in the U.S.

Online duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4423
  • Karma: 40
Re: total pressure plate lift
« Reply #1 on: 19.06. 2019 02:19 »

 When I measured my Plungers pushrod travel a while ago I think there was about 3mm, but it may depend what handpiece you have as I expect the other geometry should be the same....I guess unless the plates are squishy the travel should equal the accumulated sum of the gaps between plates. Is it dragging?
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online coater87

  • Wise & Enlightened
  • *
  • Join Date: Jul 2008
  • Posts: 1166
  • Karma: 6
Re: total pressure plate lift
« Reply #2 on: 19.06. 2019 04:03 »
Hi Dutch,

 I have everything else on the bike pretty  well sorted, last big thing is the clutch/ gearbox.

 The clutch was dragging, steadily getting worse as it warmed up. Bang into first, crunch down into second once hot.

 I just installed new plates and frictions, deburred everything and smoothed the basket plate groove slides.

 I was indicating for a square lift and noticed I am only getting .070.

 This seems too little for the cable travel at the lever (1 and 1/16 centers), but i could be wrong because of the two arms at the gearbox being unequal lengths.

 Maybe I am stretching a cheap cable, or just pulling curves out of it- i dont know as I have no other bike to compare it too.

 Lee



 
Central Wisconsin in the U.S.

Online duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4423
  • Karma: 40
Re: total pressure plate lift
« Reply #3 on: 19.06. 2019 05:21 »

 I have the same pull lever,  but;  *eek*
 
 
Quote
.....but i could be wrong because of the two arms at the gearbox being unequal lengths.

  *conf2*...... ?.....two arms ? I better have a look back at th' ranch and count the arms..... *conf2* *conf2*... no more  *beer* just yet
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online coater87

  • Wise & Enlightened
  • *
  • Join Date: Jul 2008
  • Posts: 1166
  • Karma: 6
Re: total pressure plate lift
« Reply #4 on: 19.06. 2019 05:56 »
Two.

 Shiney one outside the cable hooks too and the stubby one inside with an adjuster mounted to it.
Central Wisconsin in the U.S.

Offline Swarfcut

  • Resident Legend
  • *****
  • Join Date: Oct 2018
  • Posts: 653
  • Karma: 9
Re: total pressure plate lift
« Reply #5 on: 19.06. 2019 08:03 »
Lee. Try the slack on the pushrod adjuster under the gearbox end cover. You can get away with just the barest amount of play here, as long as there is no loading on the pushrod with the clutch fully engaged. Any lost movement here is magnified by the time it gets to the clutch lever. A stretched outer cable  is another thing to check as this can account for wasted clutch lever movement. Are the clutch and brake levers on the right way round if they have differing pivot centres?

 Swarfy.

Online duTch

  • Ricketty Rocketty Golden Flashback
  • Wise & Enlightened
  • *
  • Join Date: Oct 2011
  • Posts: 4423
  • Karma: 40
Re: total pressure plate lift
« Reply #6 on: 19.06. 2019 08:19 »

 
Quote
  Two.

 Shiney one outside the cable hooks too and the stubby one inside with an adjuster mounted to it.

 Àaah yeah- copy and paste that, I was thinking outside the box- way too far out....
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 7890
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: total pressure plate lift
« Reply #7 on: 19.06. 2019 08:28 »
G'day Lee.
With everything as per book I get 80 thou" (2mm) lift.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Online orabanda

  • Resident Legend
  • *****
  • Join Date: Nov 2008
  • Posts: 950
  • Karma: 20
Re: total pressure plate lift
« Reply #8 on: 19.06. 2019 08:38 »
Hi Lee,
What type of clutch do you have?
Richard

Online coater87

  • Wise & Enlightened
  • *
  • Join Date: Jul 2008
  • Posts: 1166
  • Karma: 6
Re: total pressure plate lift
« Reply #9 on: 19.06. 2019 10:55 »
 Thanks guys,

 Musky, so i only need to find .010 or so more. I just dont know where yet. The cable is really moving up on the suspect list.

 Richard,
 This is the suzuki clutch, but I am thinking "lift is lift" and type of clutch shouldnt matter?  *conf*
  I really want to get this clutch working correctly. As I have sorted out the bike the shifting has taken a back seat to everything else, but now its top of the list.

I bought new plates and springs from barnett, and new cork based frictions from EBC. Once I find a little more lift I am hoping everything gets much better.

 Lee
Central Wisconsin in the U.S.

Online muskrat

  • Global Moderator
  • Wise & Enlightened
  • **
  • Join Date: Jul 2009
  • Posts: 7890
  • Karma: 106
  • Lake Conjola NSW Oz
    • Shoalhaven Classic Motorcycle Club Inc
Re: total pressure plate lift
« Reply #10 on: 19.06. 2019 20:45 »
G'day Lee.
I'm wondering if with all the new plates, the total stack height is a bit high and the springs are getting coil bound.
I would have thought your 70 thou" lift to be ample for the plates to separate.
Another thought. The steel plates are pressed out of sheet. So one edge is rounded the other is square (sometimes with a slight burr. They should all be inserted in the same direction with the rounded side in.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Online chaterlea25

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 3065
  • Karma: 45
Re: total pressure plate lift
« Reply #11 on: 19.06. 2019 22:37 »
Hi Lee,
To get maximum lift on clutch the the lever on the top of the gearbox and the lever inside the inspection cover must operate as near as possible to 90 degrees to the cable and pushrod  to get the maximum lift
The inner lever is fitted on a fine spline for adjustment

Any wear on the gearbox cover where the mechanism goes through loses lift as will wear on the handlebar lever pivot
Next what center distance is the clutch lever? after market levers can cause problems

Any sharp bends on the clutch cable will cause further lost motion

John
1961 Super Rocket
1963 RGS (ongoing)

Online orabanda

  • Resident Legend
  • *****
  • Join Date: Nov 2008
  • Posts: 950
  • Karma: 20
Re: total pressure plate lift
« Reply #12 on: 20.06. 2019 01:53 »
Hi Lee,
Crunchy gear changing indicates failure of clutch to fully disengage.

With handlebar lever pulled in, the inner hub should rotate easily; negligible drag. I can turn the inner hub by using fingers in the recesses for the springs (in the outer pressure plate).

If you cannot easily rotate inner hub by hand, further investigation required. You have nearly 2mm of lift. Perhaps the surfaces are not parallel? Remove plates and check that back face of inner hub is concentric (runs true when gearbox shaft rotates).

John makes a good point about possible  excessive wear in the outer case (hole for clutch arm); check for side play.

Richard

Online coater87

  • Wise & Enlightened
  • *
  • Join Date: Jul 2008
  • Posts: 1166
  • Karma: 6
Re: total pressure plate lift
« Reply #13 on: 22.06. 2019 00:54 »
 I have gone through everything we have discussed here.

 I have not been able to take the bike out for a long ride, I have 3 days of work left.

 But the things I did find:

 My friction plates may have been getting pinched as the clutch warmed up.

 My original springs were pretty beat, they say the new springs are 10% stiffer- we will see how that works for me. I am not a gorilla by any stretch of the imagination.

 The new plates and frictions were well de burred by me. The basket also got a going over with a smooth file. The original plates were sharp and installed willy-nilly.

 I was getting barely any lift. I found where the cable goes into the adjuster at the gearbox- adjuster not drilled deep enough for the ferrule so the cable sat at a funny kink. Cut that apart and soldered the cable with a different adjuster.

 There is no slop where my clutch arm enters the gearbox- I had turned a bronze bush for this when I originally built the gearbox.

 But, the pivot point on my clutch hand control has enough slop for everyone. I have to do something about that, I may have to try and bush the lever or just replace.
 These seemed pretty good levers made by emgo at the time, maybe I need to buy better.

 I have between .070 and .077 lift now, I believe I could get to .080+ with better levers.

 I changed out the 80/90 gear lube and replaced with straight 30 weight. Might be straw clutching, but the wind is blowing pretty hard on this gearbox.

 We will see what happens, and I will report back.

 Lee
Central Wisconsin in the U.S.

Online coater87

  • Wise & Enlightened
  • *
  • Join Date: Jul 2008
  • Posts: 1166
  • Karma: 6
Re: total pressure plate lift
« Reply #14 on: 28.06. 2019 13:05 »
 I am going to say the gearbox is 80% better.

 It snicks into first, I can find neutral very easily still.

 I think the cable was quite a bit of the problem. I think changing the plates helped a lot also.

 I think changing from 80/90 gear oil to straight 30 just made the box leak a little.

 Here is a couple of new problems.

When warmed up, 2nd gear tends to disappear when upshifting. When shifting from first, neutral is now a gear stop. so I shift from first to neutral, than shift from neutral to 2nd. Before it would go 1st straight to 2nd.

 2nd is gone when coming from 3rd and the box is warm. There is no "funny" feeling in the shift, 2nd and neutral just get skipped over when coming from 3rd, the gear change wants to go straight to first, and thats pretty crunchy. I dont feel 2nd or neutral with my foot at all.

 I have adjusted the detente both out and in, and there seems little difference.

 I might have to put together another gearbox just to see the 3rd to 2nd change and try and figure this out unless someone has had this happen.

 Lee

 
Central Wisconsin in the U.S.