Problem Clutch - What a Drag..!!

[Miti]

Getting my V1000 back on the road was great... BUT...  It's been carrying a problem in that the clutch slips occasionally...

Not now... Changing the gearing and exhausts seems to have freed up more performance and the clutch slips very frequently now...

Starts at about 4.5K rpm (depending on gear selected).

So I decided to sort it ASAP ('m off to Santander in Sept and really don't need a slipping clutch for that).

First, primary cover off:

1.   Drain the oil into a clean container (I maybe re-using this, it's only done 200 miles)
2.   Disconnect gearchange linkage from gearchange crossover shaft (allow linkage to hang down)
3.   Loosen rear footrest mounting bolt
4.   Remove front footrest mounting bolt (allow footrest/gearchange assy to hang down)
5.   Disconnect generator wiring from harness
6.   Remove all casing screws from periphery of primary cover
7.   Gently tap the casing to break the bond with the crank-case face

Note:   Relocate the drain pan prior to breaking the bond as there will be some oil that escapes from the joint as this happens.

Note:  When removing the casing, the generator stator and rotor will be magnetically attracted, causing resistance to removal.  Additionally, the gearchange crossover shaft may be tight in the seal/casing.

Then we're left with this:



Hopefully, yours will not be too dissimilar to mine...

The clutch pressure plate is held in place by the force applied by the six clutch springs.  To release the plate, the six M5 allen bolts, washers and springs must be removed.

The springs sit in steel seats (known as "spring boxes").  These "float" in the pressure plate and may also be removed with the springs.

Once the pressure plate is removed, the "stack" of clutch plain and friction plates may be removed, giving you this:



At this point, it's time to dig out the manual and search for specifications... Clutch friction plate thickness and spring free length are the normal measurements to check, but my bike has a pre-production motor, so I'll also be checking to ascertain just exactly what is in there...

Note: Back in the very early days, many V1000's were plagued with problems caused by the clutch plates sticking together.  This would cause serious difficulty in selecting first when the bike was cold and also cause nasty gearchanges until the oil warmed up properly...  The problem was albeit completely cured by replacing the clutch friction plates.  For reference; the original (problem) plates were black in colour, the replacement (cured) plates are red...

Mine has neither... It has a set of nine "Surflex" plates... I doubt that mine is the only V1000 with Surflex plates though... Their S1425/B kit (Ducati 900 SD and others) is known to fit the V1000.

But, I have a set of NOS red Hesketh plates in my stash of bits and pieces... So I've compared the Surflex ones with the Hesketh ones...  They're all 3.65mm thick, which exceeds the Hesketh manual min thickness (min thickness 2.75 mm).. So it doesn't appear to be the friction plates...

I checked all the plain steel plates - fitted and NOS plates are all 1.5mm thick and there is not sign of warping or blueing, so, onto the springs...

The V1000 Workshop manual states a spring free length of 36mm (change @ 35mm).  Well, mine are all 42.25 - 42.65 mm, so something isn't right there... 

I spoke to some folks from the Ducati forums... They were very helpful and one member passed on some information regarding the Surflex clutch and its' fitment in Laverda motorcycles... They have a min free length of 30mm and it turns out that they have different spring boxes... 

Aha...!!  I turned my attention to the spring boxes... They're like a tin top hat:  25 mm wide rim, 16 mm OD on the "box" and 41 mm long... When cleaning these, I noted polished areas, both inside and out, that gave the boxes a very "well-worn" appearance...  I also noticed that one of them had light showing through it ... Whoops..!!

So, before progressing further, I gave Colin Evans (HOC Tech Guru) a call... Colin recollected the early clutch issues (his own bike had suffered pretty badly with the problem), but none concerning clutch slip...

Colin offered to take a look-see for NOS Hesketh spring boxes and as if by magic, they appeared in the post today... 

GREAT..!! (ish)   When I unwrapped the parcel, it was immediately apparent that the NOS Hesketh parts were different from the ones that came out of my bike...



The NOS Hesketh items are on the right...

The rim is the same at 25 mm, the height is the same at 41 mm, the hole in the bottom is also the same at 9 mm... There the similarties end...

The NOS Hesketh parts are made from a much heavier gauge metal (about 1.5 times as thick) and the OD of the box is 16 mm on the old items and 20 mm on the NOS items...

So, where to now..?  The new spring boxes don't fit into my pressure plate... 

Do I try to find a Hesketh pressure plate..? 

Do I have the existing plate modified to fit the NOS boxes..?   

Decisions, decisions... It'll all depend on availabilty of spares, of course...

More, as things develop...

Jeff

[Miti]

Ain't t'interweb a wonderful thing..??

I found this VERY useful spring rate calculator on a manufacturer's website...

Taking the dimensions from the springs I found fitted to my V1000 clutch, I get a spring rate of 57 lb/ins...  Multiplied by six gives a clamping pressure of 342 lb/ins...

Playing about with some bits and pieces from other bikes (some owned in the past, some still owned), I found that the springs from an XS1100 clutch are a very good fit in the spring boxes that Colin sent up...

Entering the dimensions from these springs into the online rate calculator (assuming that they would be fitted in the Hesketh) came out with a rate of 71 lbf/ins and a clamping pressure of 426 lbf/ins...  That would be a near 25% increase...

Hmmm... That could be interesting... 

More, as it develops...

Jeff

[Miti]

Mick B has come up with the goods... 

Here's a cropped version of the OE Clutch Spring drawing...



(I thought these bikes were supposed to be 'metric'..?)

Converting to millimetres:

Free-Length = 36.449 mm (This ties in with the figures from the V1000 manual)
OD = 17.339 mm

Aha..!!  That's the 'magic number@..!  Or at least one that unlocks this mystery...

The OE Hesketh springs would never fit into the spring boxes that came out of my bike, or the pressure plate... (boxes are 16.00 mm OD and the holes in the plate are 16.6 mm)

I spoke with that nice Mr Sleeman, who kindly sent me a photo of a pressure plate... Guess what..?  It looks to have 20 mm holes for the spring boxes...

There may be light at the end of this tunnel...

More, as it develops...

Jeff

[Miti]

Spoke to my friendly neighbourhood CNC machinist yesterday...

I've worked out (after measuring EVERYTHING twice) that the clutch springs, boxes pressure plate, et al have a PCD of 63.499 mm (or 2.499").  It's likely that the OE drawing has the PCD set at 2.5"

So he's going to open up my clutch pressure plate to suit the OE Hesketh spring cups...

Should be done by Wednesday...

Photos soon...

Jeff

[Miti]

Joe (Sprite Engineering, Lenziemill, Cumbernauld) brought my pressure plate over to the house last night... (he was after an excuse for a ride while the weather is fine).

He's modified it to accept the larger (Hesketh) spring boxes, retaining the 2.5" PCD that all the rotating clutch components share...





(as always, apologies for HUGE photos - use right/left/up/down keys to view)

I'm going with the XS1100 springs ('cos I have a set handy).

Joe says that he's seen quite a few Brit bikes with similar set-ups and agreed that the old spring-boxes appear to be too small for such a large bike...

Anyway...  I put the clutch back together last night...

• Checked and cleaned "Surflex" friction plates
• "Glazed busted" plain plates (400 grit wet/dry)
• Modified pressure plate (probably the same as all the other V1000s now...)
  
  • NOS Spring Boxes
  • XS1100 (OE) springs
  
  The new springs are wider than the ones that came out, so the retaining washers are too small in diameter to retain them properly... Looking about on t'interweb, I couldn't find suitable washers to suit both the springs and the M5 screws... So, I've gone with some M6 SS jobs and counter-bored them to accept CSK screws... I've bought some 10.9 HT CSK allen screws and the whole shebang went together very nicely...
  
  
  
  I oiled all the plates as I went along and made certain that the release bearing was well oiled too...
  
  After adjusting the push-rod/bearing clearance, it was time for the big test...
  
  The clutch works fine... In the garage...  The plates separate very well (quite a stroke on that push-rod) and there is no sign of the "alien" springs becoming coil-bound...
  
  There is a slight increase in the lever pressure required, but it's not as stiff as other bikes I've ridden...
  
  Test ride tonight, if all goes well...
  
  Jeff

[Miti]

Apologies for the delay in continuing this thread - we've been on our holly-bags and the V1000 has been sulking in the garage for a couple of weeks... Something else will have broken now, 'cos she doesn't like to be left unattended for so long...

I've modded the previous post to add photos... It occurred to me that eagle-eyed readers might spot the allen bolt sticking out of the clutch centre, so I'll explain... I assembled my (now closer to standard) clutch with the adjuster unlocked and backed off almost to the point of removal...  The parts went together without any issues - until I came to adjust the bite point... As soon as the point where pressure starts to slightly lift the pressure plate was reached, the adjuster fell neatly into two parts...

On close examination, the adjuster is hollow for about a third of its length...  The point where the locknut and centre meet is in this hollow region and the wall thickness is something about 0.5mm.  It appears that, at a previous adjusting session,  I've overtightened the adjuster to the point of fracturing this thin tube...   The allen bolt was a temporary substitute adjuster...

I've covered about 60 miles with this new clutch arrangement... Seems to be OK so far... There is a little bit of "snatch" at the point where the clutch finally bites, but overall seems to work fine...

Unless the situation deteriorates again, I'll close this topic off... Might even add the XS1100 springs to the list of alternative spares... 

Jeff

[Rob B]

just a hint if you want to sharpen up the clutch action remarkably, and get it to release properly for a far better gear selection. Throw away the original soggy, rubbery 35 year-old Brembo clutch pressure line and replace it with a nice neat black braided item from NBM Woolford or equivalent. Clutch action is transformed but take care when you first pull away ! :-)

RB