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LM1 Clutch and Flywheel

Printed From: guzziriders.org - moto guzzi forum
Category: Technical
Forum Name: Big Block Tonti
Forum Description: Spada, Le Mans and Cali
URL: http://www.guzziriders.org/forum_posts.asp?TID=9507
Printed Date: 28 Mar 2024 at 17:59
Software Version: Web Wiz Forums 12.03 - http://www.webwizforums.com


Topic: LM1 Clutch and Flywheel
Posted By: GuzziPaul
Subject: LM1 Clutch and Flywheel
Date Posted: 02 Dec 2018 at 20:30
Anyone any idea what this clutch and flywheel is? And what special tools I'm going to need? I'm doing an end ceankshaft seal replacement. There's 8 allen bolts which I guess I unscrew. The central boss is removable and I guess I need to get onto the central flats somehow. There is a black mark at about 3 o clock on the outer ring and in the middle a white mark. I have not yet set to TDC ( on the right) which I will pop the gearbox on before doing




Replies:
Posted By: GuzziPaul
Date Posted: 02 Dec 2018 at 20:34
Overview picture. Its a Surflex clutch, thats all I can make out.



Posted By: Mike H
Date Posted: 03 Dec 2018 at 00:27
Yup that's a special lightened jobbie. But looks like attachment to crank is standard.







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"Chicken nuggets don't dance on a Tuesday."


Posted By: Mike H
Date Posted: 03 Dec 2018 at 00:28
PS: the starter ring gear teeth look very worn, or they are meant to be that shape?



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"Chicken nuggets don't dance on a Tuesday."


Posted By: dan_s
Date Posted: 03 Dec 2018 at 07:50
Use new bolts for the crank, 10.8 tensile strength or more. Also new spring or schnor washers.
You can realign the clutch with the transmission sprocket with gearbox in hand for reassembly but it would be easier if you had a separate sprocket for that.
Ring gear teeth will usually do even if they look worn. I guess removing burrs from the teeth won't do harm.


Posted By: Brian UK
Date Posted: 03 Dec 2018 at 08:01
The ring gear teeth usually have an odd lead in profile when new. Something to do with helping the pinion mesh more easily and quietly.


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Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: Gianni
Date Posted: 03 Dec 2018 at 10:00
Originally posted by dan_s dan_s wrote:

Use new bolts for the crank, 10.8 tensile strength or more. Also new spring or schnor washers.
This.
 
This is the most important advice here. Everything else might underperform or fail awkwardly. The flywheel coming loose will fail catastrophically.


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Le Mans 1, Spada, Cali 1, T3 Mongrel, Le Mans V, Quota x 2, Stelvio TT


Posted By: Kidneb
Date Posted: 03 Dec 2018 at 16:37
The correct bolts for the flywheel is grade 10.9   
https://hmb-guzzi.de/Screw-flywheel_1" rel="nofollow - https://hmb-guzzi.de/Screw-flywheel_1
https://www.quora.com/Which-is-stronger-12-9-or-10-9-steel" rel="nofollow - https://www.quora.com/Which-is-stronger-12-9-or-10-9-steel




Posted By: dan_s
Date Posted: 03 Dec 2018 at 17:12
Originally posted by Kidneb Kidneb wrote:

The correct bolts for the flywheel is grade 10.9  
You are correct


Posted By: GuzziPaul
Date Posted: 03 Dec 2018 at 22:13
The flywheel bolts are going to be replaced definetly. On the first Le Mans I had when I did the clutch on that back in 1983, I used bolts thread right up to the head. They sheared off on the M11 near junction 8 on the way to France from East Yorkshire. AA relayed back home overnight. Got home at 0600, engine out, took it into work to the fitters on a sack barrow (no car). Bolts extracted, new bolts turned up with shoulders and locked wired in and set off again at 1600 the same day.
Forgot to put a split pin in the footbrake pivot which I didn't find out till braking into a roundabout on the A1 near Peterborough, but a cable tie  held it all the way to St Tropez and back.


Posted By: sardineone
Date Posted: 04 Dec 2018 at 00:24
Have you verified that a porous engine casting didn't oil your clutch plates??  Happened to my Lemans IV not long after new.  As for tools a pressure plate compression tool makes installing the new plates without accidently warping the plates on assembly much less likely.  I made my own with a large bolt that threads right into the end of the crank with a nut and washers to compress the pressure plate while putting the clutch plates in.
Also a stuck crankcase breather valve (a large ball bearing in a housing like a PCV valve) can stick when moisture blends with oil at this valve showing a milky brown goo around the ball.  Result can be a belching of oil on the clutch plates from over pressure of the crankcase.


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George

One owner 86' Lemans 1000 (member of the family) / BMW R1200ST (current work horse)

You are what you have ridden!


Posted By: GuzziPaul
Date Posted: 04 Dec 2018 at 20:38
Clutch is off and plates are oily. Don't think the oil is coming from the crankshaft oil seal, it's either the gasket of the breather to the top right, the returns at the top or the aluminiuminium washers at the bottom.




Posted By: jpc
Date Posted: 04 Dec 2018 at 21:12
Don't overlook the bearing carrier gasket, the two bottom bolts that communicate with the crankcase and should be loctited, and the camshaft blanking off plate that's been known to leak (it's only pressed in and sometimes requires a bead of sealant).
The bolts normally have tab washers, torque is 3 mkg.


Posted By: Gianni
Date Posted: 05 Dec 2018 at 15:00
I've had a leak past the Jubilee clip at the bottom of the big breather connection to the LM breather box. It dribbled down into the clutch housing and appeared at the bottom of the gearbox through the lever window. Looks terrible, five minute fix after three hours diagnosis of course. Had to remove the breather box to find out. The oil on the inside of the upper part of the breather pipe was the clue - and the split loose pipe. Cry

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Le Mans 1, Spada, Cali 1, T3 Mongrel, Le Mans V, Quota x 2, Stelvio TT


Posted By: Mike H
Date Posted: 05 Dec 2018 at 15:25
I've had this too.



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"Chicken nuggets don't dance on a Tuesday."


Posted By: Kidneb
Date Posted: 05 Dec 2018 at 16:19
Plenty of good advice and suggestions here, but there's one thing I don't see mentioned;
Plates are oily you say, that could very well indicate leaking clutch pushrod seals. That would allow gearbox oil to migrate right into the heart of the clutch.
You could of course be experiencing multiple leaks on the old girl !
Why did you take it apart, slipping clutch,- dripping oil ?



Posted By: Mike H
Date Posted: 06 Dec 2018 at 12:02
He says (in OP) to replace crankshaft seal. Normally not easy for oil to get into the plates from there, but this is a fancy lightened clutch, so who knows; even so you still may have a point.





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"Chicken nuggets don't dance on a Tuesday."


Posted By: GuzziPaul
Date Posted: 06 Dec 2018 at 13:01
Originally posted by Gianni Gianni wrote:

I've had a leak past the Jubilee clip at the bottom of the big breather connection to the LM breather box. It dribbled down into the clutch housing and appeared at the bottom of the gearbox through the lever window. Looks terrible, five minute fix after three hours diagnosis of course. Had to remove the breather box to find out. The oil on the inside of the upper part of the breather pipe was the clue - and the split loose pipe. Cry

Yes, I think that may be it, it does look a bit oily round there and the bottom jubilee clip was loose. I've ordered an o-ring to slip in there as well as a new gasket for the breather which I also think is leaking.


Posted By: GuzziPaul
Date Posted: 06 Dec 2018 at 13:11
Originally posted by Kidneb Kidneb wrote:

Plenty of good advice and suggestions here, but there's one thing I don't see mentioned;
Plates are oily you say, that could very well indicate leaking clutch pushrod seals. That would allow gearbox oil to migrate right into the heart of the clutch.
You could of course be experiencing multiple leaks on the old girl !
Why did you take it apart, slipping clutch,- dripping oil ?

 The central bearing carrier area is dry and clean so I don't think it's coming from the crankshaft seal. The central area of the clutch is also dry so don't think its coming from the gearbox.

The clutch wasn't slipping,  it was (mostly) the oil at the back of the engine, on the stand etc. I've also identified that the UJ boot was split and that "may" have explained some of the oil in the area outside but not at the bottom and right of the bellhouse.

I cleaned it up last night and I'll give it another long hard look tonight.


Posted By: swede
Date Posted: 06 Dec 2018 at 15:32
I had mine like that and it turned out to be melting waxoyl, that I had sprayed on the engine (for an Elephant rally) finding it's way down, into the clutch housing, from up between the V. Presumably, an oil leak would do similar?  When you put it back, I cut 2 pieces of hardboard, the length to fit across the centre plate splined holes in the middle, and made them interlock by cutting a slot half way across their centres so the two interlocking pieces made a cross which fitted though the splined centres of the two plates and kept the plates lined up. Hope that makes sense!                                                                     Use longer bolts to start pulling the ring gear plate in untill the original screws reach.                               Note the painted mark on the flywheel and crank centre or your timing marks will be wrong on the rim.
   There is a mark, also (indent, not paint) on the plain centre plate teeth to flywheel inner splines.  
   My flywheel centre screws have been ok not replaced but toque them correctly and loc-tite them (154000 miles so far)
   I super glued the springs into the recesses in the back of the plain centre plate as the springs can not locate into them and it makes getting the plates and things back together easier with only 2 hands.
   I use a smear of high content moly-grease on the moving parts. ( get it on ebay)
   I hope that all helps, I've done it a few times so it's what I've evolved by trial and error and by being a mechanic for over half a century.    


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swede in the shed


Posted By: simonnorthroad
Date Posted: 06 Dec 2018 at 15:39
Yes Ill second putting sealant or better JB-Weld round the circular camshaft-tunnel 'coreplug' rim, at the top of your picture.

Mine popped-out of place in Normandy en-route to Dijon under routine crankcase pressure and belched all its oil everywhere = game over 


Posted By: swede
Date Posted: 06 Dec 2018 at 16:35
I don't think clutch push rod seai an option. it will leak into that centre piece that the push rod pushes forward and, on your picture, that looks dusty dry.

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swede in the shed


Posted By: Kidneb
Date Posted: 06 Dec 2018 at 19:04
Originally posted by swede swede wrote:

I don't think clutch push rod seai an option. it will leak into that centre piece that the push rod pushes forward and, on your picture, that looks dusty dry.

Yes- you're right of course. I just had the oily plates in mind and forgot to look at the picture.


Posted By: GuzziPaul
Date Posted: 10 Dec 2018 at 20:42
Think the leak is a combination of the opening for the top of the two breathers and the brether feed, so ordered a new gasket.
Going to use the clutch hub centre to line the plates up, managed to find the centre bolt from the last "special tool" I made 34 years ago for my first Le Mans.
Had to make my own special tools to get the centre nut off. Is the hub centre threaded on because I'm have no look getting it off )I have removed the washer.



Posted By: Mike H
Date Posted: 10 Dec 2018 at 20:57
Originally posted by GuzziPaul GuzziPaul wrote:

Think the leak is a combination of the opening for the top of the two breathers and the brether feed, so ordered a new gasket.

If you can/have ascertained it is engine oil. I just remembered, in the factory workshop manual it says, bearing in mind it is translated from Italian,  "if the oil smells bad then it is from the gearbox"

Big smile






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"Chicken nuggets don't dance on a Tuesday."


Posted By: GuzziPaul
Date Posted: 15 Dec 2018 at 09:51
Trying to find the torque settings for the 6 flywheel/crank bolts. I've got this  http://www.thisoldtractor.com/mg_manuals/torque_specs.pdf " rel="nofollow - http://www.thisoldtractor.com/mg_manuals/torque_specs.pdf  ;  but can't identify the appropriate component bolt.  I've got my Loctite ready, new HT bots and a choice of three torque wrenches. Just no idea how much "grunt" to give them.


Posted By: Chris950s
Date Posted: 15 Dec 2018 at 10:51
My workshop manual (which covers G5. Le Mans II, 1000 SP and T3) gives "Bolt, flywheel to crankshaft 4,2 kgm (30 ft/lb)" 

I hope this helps


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Chris and Karen - Essex
2011 Stelvio NTX, 1974 950S (750S replica nearly rebuilt!), 1966 Triumph T100SS 58 years young this year!


Posted By: GuzziPaul
Date Posted: 15 Dec 2018 at 13:45
Found it eventually. Only to realise the new HT bolts I ordered from my usual place are the wrong pitch 1.0 rather than 1.25. So that this weekends plan out the window.


Posted By: GuzziPaul
Date Posted: 24 Dec 2018 at 16:04
What pitch is the internal thread at the end of the crank so I can pre-compress the clutch? It's M12 but not !.25 pitch


Posted By: sardineone
Date Posted: 24 Dec 2018 at 16:35
The pitch on my 86' Lemans is 1.5 and I'd be surprised if yours is different.  I made my own pressure plate compression tool with a M12 1.5 pitch bolt.
 


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George

One owner 86' Lemans 1000 (member of the family) / BMW R1200ST (current work horse)

You are what you have ridden!


Posted By: jpc
Date Posted: 24 Dec 2018 at 16:35
You can pre-compress the clutch by temporarily fitting 4 longer bolts around the periphery.

(and use crankshaft thread only for centering and aligning the splines) 



Posted By: sardineone
Date Posted: 24 Dec 2018 at 16:56
I have a left over inner carrier from when I switched from original to a deep spline clutch and my tool fits inside it.  I had compressed the springs with the plates in place in the past and that's the tricky part not to catch an clutch plate edge or unbalance the pressure ( I inadvertently warped plates that gave me an on-off character clutch).  Using my cheap easy tool insures a as new clutch operation when assembled.

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George

One owner 86' Lemans 1000 (member of the family) / BMW R1200ST (current work horse)

You are what you have ridden!


Posted By: ReggieV
Date Posted: 24 Dec 2018 at 17:48
Originally posted by sardineone sardineone wrote:

The pitch on my 86' Lemans is 1.5 and I'd be surprised if yours is different.  I made my own pressure plate compression tool with a M12 1.5 pitch bolt.
 
 
As sardineone said, I can confirm that the pitch is M12 x 1.5 for the flywheel centre hole.
 


Posted By: GuzziPaul
Date Posted: 25 Dec 2018 at 17:48
Thanks all.





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