speedymoto clutch spring/cap incompatibility issue

[h_bakken]

I have a 2008 S4RS and had the DP slipper clutch installed.  I also had the DP slave cylinder put on at the same time to decrease lever effort.  I later replaced the clutch springs and spring caps and bolts with a kit from Speedy Moto.  Every time I rode, the spring retainer bolts were becoming loose on their own.  I took the Speedy Moto parts off and put the old parts back in (the DP slipper uses the stock springs but replaces the caps with black anodized aluminum ones).  In doing so I noticed that the Speedy Moto caps are about 4 mm deeper than the DP caps and think this may be the source of the problem, as even with the retainer bolts fully tightened down the springs are not as compressed as with the shorter (DP) caps.  I have not yet ridden the bike since (but I have been riding with a hex-wrench in my back pocket and checking the bolts every stop).  Has anyone else noticed this or a similar problem?  My apologies if this has already been discussed.

[He Man]

i think ducati switched the caps around that year. I picked up an entire S4Rs clutch and noticed the caps are different. they are thicker around the lip as well.

[Düb Lüv]

i just did the almost the same thing as you. yoyo slipper and speedymoto caps and springs. the first thing i noticed was that the speedymoto springs are shorter than OE ducati ones. i know with some aftermarket retainers there are clearance issues with some pressure plates, but i don't think you'll run into that problem.

have you been tightening the retainers all the way down to the clutch hub studs? when the bike's not running, have you pulled the clutch lever and looked at the clutch, to see if there's any binding? are any of the bolts stripped?

i'm really curious about what's going on.

[h_bakken]

I have tightened the bolts all the way down so that the retainers are contacting the clutch hub studs and none of the bolts are stripped.  There is no binding when actuating the clutch, and other than slippage under full throttle when the bolts have managed to back themselves out thus reducing the pressure on the clutch pack, I have noticed no malfunction.  I am convinced that the thicker body of the retainer cap does not allow the spring to be tensioned properly, as the extra thickness is between the undersurface of the head of the spring retainer bolt and the clutch hub stud, so the bolt actually cannot be inserted as far, thus reducing spring tension.  I can easily see the difference now that I have put the DP caps and springs back in, because before, there were several millimeters of spring visible extending past the collars on the DP pressure plate and now there is almost none visible.  I will update after my next ride (but will continue to ride with a hex key in my back pocket as well....)

[Düb Lüv]

having you been torquing the bolts to spec? i think it's something like 8 or 9nm. i don't have a torque wrench that small so i snug them all up, then maybe an 1/8th of a turn. i know it's more than spec, but like you that's something i don't want coming loose. you could also try a drop of low strength threadloc.

[He Man]

even greasing the bolts and then apply the proper torque might help, i had clearance issues with the S4Rs caps. i just went back to the stock caps. they are rusty, but you cant see them with my clutch cover anyway.

[h_bakken]

If they come loose on my next ride I will use blue loctite.  I don't remember the actual torque spec but I do remember that neither of my torque wrenches had a low enough setting so I just tighten them down until they stop and then finger tight (fingers on the short end of the allen wrench).

[He Man]

i would use green instead. i just dont like the idea of blue locktite on those post. really just using a little bit of grease will help you properly torque them.

[h_bakken]

does anyone know the actual torque spec?  I seem to remember 8 nm (or 8 inch/lb?)  I got a new 1/4 inch drive torque wrench today which can go down to 6 n/m

[DucNaked]

5-7nm

[h_bakken]

Just an update -  Thanks for the torque spec BTW.  No more loosening as of yet but ANOTHER interesting finding.  I have the DP slave cylinder and also have small  hands (I know what you are thinking...)  Anyhow, I had the stock clutch lever adjusted to be as close to the bar as possible.  When I rode on hot days (VERY rare here in WA state) I noticed that the effort required to shift gears (foot control) seemed to get harder and more difficult during the ride.  Turns out that the combo of the short clutch lever throw combined with less clutch actuation due to the bigger area of the DP slave cylinder was making the clutch just barely disengage at 'full pull' on the hand control, and as the clutch pack heated up and expanded, it was not fully disengaging, resulting in hard shifting, and at the worst, creeping at stop lights.  So I turned the adjuster a couple of clicks and VIOLA, problem solved...  Hope I didn't damage the transmission but it seems fine.