clutch nipple bodge?

[DaveTomo]

Just after some re-assurance I suppose , Rebuilding the clutch today -MB deep crownwheel ,ScootRS spider & at the time a standard GP clutch bell & a Readspeed 5 plate clutch.Have used the Readspeed kit before, bought a new one for this year as the other was on its last legs after some years good service.This time I decided to fit standard steels as oppose to the thin type that come with the kit to beef it up a little.Anyway to my point to get the correct clearance I needed a deeper clutch bell, the only ones I had to hand were all LI/SX/TV type one of which a Winco type (bought from AF years ago) is deeper than a standard bell.

Anyway I have a GP sidecasing - I know I could have left the brass plunger off and used it LI/SX style and kept the nipple on - but I prefer the GP type as I believe (rightly or wrongly) that it spreads the load a bit better.So! to my point, I cut the nipple off ( see picture below), the centre is still there just not the nipple, anyone else done this ? and did it work OK long term?

[HxPaul]

The only problems that I can see is,have you ground the surface perfectly flat and is the surface of the clutch bell still hardened,having said that the plunger that the GP sidecasing uses is brass,so the hardening issue shouldn't be a problem.

[Knowledge]

I have acquired from Martin Hyland a ScootsRS nippled centre with a spindle to suit my Li 150 gearbox. I intend to use a GP sidecasing.

I will grind off the Li nipple before use.

[Wack]

I've ground the pip off before when using a drilled cluster and a GP sidecase, works fine. If you can smooth the ground surface , even better.

[Warkton Tornado No.1]

My belief & experience is that the ‘clutch release thrust surface’ requires materials suitable for the load which is dynamic in terms of rotation (& vibration!) & static in the thrust, or load.

Initially, what Innocenti did was have ‘hard on hard’ with the clutch centre thimble pushed by the cam.

Later they had ‘bearing surface on hard’ with the clutch centre pad pushed by the bronze alloy pad.

As a point of reference, I doubt the change came about to improve performance but almost certainly through cost saving.

It is unlikely that the older set up (with the clutch centre having a spindle that fitted into the bored gear clusters of the day) could be bettered by the subsequent changes, other than from the perspective of cost in manufacture.

So my own, somewhat cynical belief, is that the mechanics of the clutch disengagement is best if the process avoids the inner clutch tipping in anyway relative to the outer clutch.

The bronze alloy pad utilised in the GP cover is probably the second best choice.

Back to your dilemma, the surface depicted (nipple cut off) should ideally have been a bit flatter & smoother than it appears. However, despite it only being about as hard as mild steel, it is still a harder surface than the pad, so the pad will be the item most likely to wear.

If I were you, & presuming you have since finished the rebuild, I would run it as it is but look out for a hardened centre from a motorcycle clutch that can be persuaded to fit into your inner clutch centre to give you a better surface as well as avoid the likelihood of tipping that I’ve tried to explain. Something along the lines of the item I have included photos of here. I apologise for the poor quality but I hope you get my drift in trying to help….

DSCN3559.JPG

DSCN3558.JPG

[DaveTomo]

Thank you chaps - HXPaul, Knowledge,Wack & Mr Tornado - appreciate all the feedback & advice.I'll run it as is for now and monitor it and see how it goes - I have smoothed the area a bit more since the photo was taken.Warkton Tornado No1. I like that idea about the hardened motorbike centre I'll keep my eye out for one of those thankyou.