Cosa clutch fine adjustment, but something else……..

[sime66]

It’s a real shame because everything else is great; starting first kick even after repeatedly stalling whilst playing with clutch cable, picking up lovely, good acceleration, ticking over smooth, no air or oil leaks; just can’t yet sort this clutch.
Three things I’m thinking about:
· Whether the radiused cut-outs need to be squarer, or deeper – some of the extra depth is wasted because of the small corner radius.
· Whether the stack of plates and corks is too deep because of swollen corks – and what the correct combined depth should be. I’ll clarify, just once more, that these corks were not left swimming in a bag of oil; I’m not sure how or why that impression was taken. The corks were soaked, the clutch assembled, and stored assembled, for a couple of weeks in the end, in a sealed bag. They were dry when I took the clutch apart yesterday, not swollen, that’s why I re-soaked them yesterday.
· Whether this very slight warping of the thick plate might be a problem; when I have the clutch out again I’ll photo and measure it properly to see what others think. I have no experience to know whether the amount of warp is insignificant, or a fundamental problem.

I know I can buy just a thick plate, or a set of plates and/or corks. But I had it in mind to buy just a banded basket sometime soon, and re-use these plates, corks, and cogs, but if some of these are knackered I’ll have to rethink. I’m not about to chuck a load more money at it until I know what the problem is.

The one thing I can do without wasting more money is take the clutch out again and make the cut-outs deeper and less rounded, and make sure the cork tangs can travel the full depth. That costs nothing, and will make certain whether or not the basket is the problem. I’ll also measure the corks, and show some detail of this thicker plate warp.

That won’t be for a couple of days at the earliest, during which time I’ll see what I can find out about cork thickness etc.

[henri]

a warped plate will give you drag ,i have heard of guys correcting very minor warpage by polishing/grinding it on a plate of glass ,but that wasnt on a vespa but a clutch that was unobtainable spares wise.if youve got any warpage replace the plate ,will check my notes/manuals for the specs on cork thickness an pm them to ya if you havent got them already ,as usual am away from home til monday so cant do it til then ,but the sip technical bit an there forum should have the info if ya cant wait,whenever ive had to ask them anything theve always got back to me in under 24 hours ,
dont lose hope mate ,your nearly there,an still with loads of summer left to ride in, Henri

[pxguru]

Agreed a warped plate will do this. Slots are deep enough already

[sime66]

Not lost hope; it's just tweaking and buggeration.
Having an afternoon away from it, that's all.
Tomorrow/Tuesday, I'll have the clutch off again.
Very much prime suspect is slight warp on thick plate, and I'll put some specific dimensions and photos of that, and cork dimensions too just to check them. (Will find data tomorrow).
If you three are in agreement, I'm pretty convinced, and you've given me something to go on, so I'll have another crack at it.
Plus side is I've learnt a good bit about clutches too.
Cheers chaps.

[vespasco]

Stick at it !!
It does seem the warped plate coupled with no oil would defo give same symptoms.
You should not really need the extra spacer now with the deeper cutouts.
Change the warped plate.
Soak the others
Double check you reassembled correctly.
Fit it. Pray. Tension the cable as it should be.
Rub ya lucky rabbits foot. Try it without the engine running first. Push it in fear etc.
if it feels good then go for it.

[sime66]

Lazy afternoon done, clutch out again; there’s still no damage to clutch, housing, or cover, so that’s all good.
The circlip had spun round a bit though, because I know I put it so the opening was not in a gap. Don’t know if that’s a problem, probably me squeezing the clutch so much, riding along and fighting the gears.
I still think my cut-outs need squaring-up at the bottom, and below is a photo, which I thinks shows the tangs fouling the radius, but I stand to be corrected. I’m waiting for the plate and some other bits now, so I’ll just spend a little while doing the corners a bit tidier and equal anyway.
As best I can I’ve shown the depth of my stack of corks and plates as 18.5mm, which ties up with SIP data, also shown below.
Trying to show such a small deflection on the plate was difficult, so I did a short film of one side lifting if I pressed the other down – a very small distortion, but significant?
I’m going to have a much more thorough check of each item for bends and burrs before I reassemble with new plate.
For now, I’ve got to clean up and get on with other jobs……

Photos (you know you love 'em)







Deflection of thick plate (it's hard to show):
s1290.photobucket.com/user/sime6954/media/P1120779_zps57236270.mp4.html











.

[vespasco]

Just a quick tip.
Those cutaways need a radius corner, not so much for the plates but for the longevity of the clutch basket.
Square corners are more likely to crack than a radiused corner. This is why you have radiused corners on many components.
Be sure to give a quick bench test before fitting.
Good luck.

[sime66]

Yep, I made them radiussed for that reason when I made them deeper, but was wondering if I'd overdone the radius and defeated the object.
I spent a lot of time on it, and I'll happily leave them alone (saves me a poxy job).
Will be bench testing and having another bash up the lane before you know it! Good news before week's out............
Cheers,

[pxguru]

How much gap can you get between the top plate and the circlip when it is compressed? More than 1mm is enough. If not is more filing but keep the radius!

If it doesnt judder when you pull away, you might as well keep the thin spacer until you get a new thick washer on your next order (there will be one).

The bottom plate is warped. Should be totally flat. And is certainly not helping.

[sime66]

Thanks,
I guess that explains it then.
I hadn't realised they had to be so precise - I've just had a really close check; none of them are totally flat.
I'm going to get a new set.
Given that they're all out, it must be sensible to assume the corks have bent with them.
Hey ho, I'll spend some cash to save more wasted time; I'll get a full set organised.
Thanks again.

[sime66]

As soon as I start looking into getting the right corks and steels, I come across this on Wasp site.
It says that the notched plate is meant to be bowed. Does that ring any bells with anyone?
Is the notched plate I have bowed because it's supposed to be?

[vespasco]

I just checked a new box of newfren plates and yes , it appears this particular plate mentioned is indeed bowed by the amount you said.
(They will also need all the sharp edges smoothed off).
When you rebuild your clutch
Recheck your big brass bushing goes on tight-ish.
And recheck you have the correct thin brass shim (cosa ll - raised external lip)
Check the main drive plate spins freely.
Check all springs are properly in the locating holes.
Check you have enough separation.
Ive found that an old rear wheel bearing is perfect to use when you compress the clutch. With this in place on top of the clutch basket you can spin the clutch whilst under compression. Checking / feeling for anything obvious.
Good luck.

[sime66]

New Newrfren set of steels, corks and springs ordered yesterday, which I’ll go over thoroughly before assembly.
The clutch was not the item to try to save a bit of expense; doing so has wasted a couple of weekends, and has cost me the extra money in the end anyway.
You learn from these experiences, no point flogging that dead horse any longer, so moving on, hopefully now with suitable kit:
1) All of what you said is clear to me, but I’m just going to check the bushes; I have a spare hour to investigate, but below is a photo of the bushes, which I think is as you describe; there is a raised edge on the shim, which faces down.
2) The springs sit on pegs. I note on upgraded clutches these are welded; I'm a bit concerned that mine are slightly loose, but probably just looking for reasons now.
3) I'm wondering if my circlip rotated because the basket is already spreading.
Will do the ‘old-rear-bearing’ test and generally be as thorough as I can, and go over everything that’s been mentioned in previous posts.
I know it’s dragging on chaps (no pun intended); but if you’ve had enough of this thread, imagine how I feel.
If it doesn't work this time, I'll live with it until I can afford a banded Cosa.

[vespasco]

Well, you have the correct shim.
The larger brass bush should not be a sloopy fit. No way of telling from a photo.

You could possibly?? borrow a known working clutch before you spend your $$
Just to eliminate other possible concerns.

Its possible that, because the clutch was too dry, that it bound itself to the circlip??! Just a thought.
Im really hoping all your probs will be solved by well a lubed clutch.

[sime66]

The other bush is a nice fit.
There’s no possibility of borrowing a clutch here; I’m very much the only boy in the village. – I know what you mean about ‘other possible concerns’ though; this is just about stopping the clutch drag, before checking everything else out. I’ve encountered and imagined all sorts of possible problems, from probably reading too many nightmare stories now.

I had a really good scour of other forums, and manufacturer’s info last night, and I won’t mind too much if the new plates and corks don’t fix it because I’m not at all happy about using a used, unbanded Cosa now I know a bit more anyway. I reckon I’m going to get a banded basket and a reinforced circlip ASAP, before I have a repeat of the damage I just had from my Mk1 clutch.
Given the tolerances we’ve been talking about with the plates, I don’t see how this much movement of the spring rivets can be acceptable:

FILM
s1290.photobucket.com/user/sime6954/media/P1120781_zps2f361cf7.mp4.html
It might even be more sensible to not put this back in at all, any opinions?

I see that a reinforced circlip seems good insurance against that problem too.

I’m going to tidy all the burrs etc., soak and bung these corks in, and if it’s still giving me agro, I’m going to hold off more mods until I’ve got something like this







Unfortunately I’m not sure, until I try it, that I made enough room in the casing for a banded Cosa, so that might be a bit of a palaver.

Anyway, this subject might be losing steam before a solution is found, and my enthusiasm for it is waning at the moment.

- Waiting for the delivery, going to have another go, and then a rethink.............

[joey]

Bloody flip...........

had you shown that from the get go we could have all shouted in unison "there's your problem!!!"

That basket is as much use as tits on a fish.

Really don't think you need to go to the extra expense of a banded one on a standard though.

I'd also be checking cush drive to see if it's that that has caused the rivets to come loose.

[sime66]

Cheers Joey,
Bought it in good faith as checked and rebuilt. Only took it apart because it was dragging, and been working through the possibilities since whilst knowing bugger all myself, and learning as I go. First time I’ve taken one apart; didn’t know what to look for at all. Bloomin’ do next time though. I mentioned the loose spring pegs yesterday, but did the film this morning because it still worried me.
The channel depths, the spacers, the bushes, cork thicknesses, the 2nd plate notch, plate thicknesses, which plates are supposed to be bowed and which ones are buggered if they’re bowed, these rivets – all new information to me, picked up a bit at a time, relying on reading whatever I can find, and the Forum………….
I only just checked my cush drive when I rebuilt the engine, this was only in the same engine for five minutes test  afterwards anyway; barely got going on it and very gently - not long enough for either of these to effect the other surely.
Not sure what you mean by a standard (standard 200?); it’s a 177 kit with a 200 carb and a Sip R2, and I’ve just ripped up a Mk1 clutch too; I’m heavy and ride pretty lively. I can tone it down a bit, but I’m not going to ride like a girl, worrying about my clutch all the time. The previous exploding clutch is the cause of the last two-month saga after all.
Anyway, thanks for confirming it; I thought that was going to be the response after last night’s reading.
There’ll be no more progress or questions for a couple of weeks, until I get a new basket, probably July - lovely.

[joey]

Still think banded is a bit of an overkill.
I know a few don't rate them but I've only had a standard cosa clutch let go once (rivets!!!!) and that was on a Malossi 210 being ridden hard.
Still use one on my Polini 207, which is a lot more torquey, and had no problems. I do however give the basket a bit of a whack every time I remove the clutch just to reduce any spread.
Just for the record the worst spread I've ever seen on a basket was a banded one purchased from Beedspeed, perhaps the welding process actually softened the basket?
Anyway, the choice is yours, but if it were up to me and I really had to have a strengthened basket I'd save up the extra pennies for this..............

SIP RACE CLUTCH BASKET

[vespasco]

As per joey.

That cush drive was always my concernn but thankfully, it looks like youve found the problem

edit. The welding/heat process could weaken the joint, not necessarily soften it. 
This is the main reason i will not buy a bandd clutch, especially a cheaply produced one. 

[sime66]

Some good news at last:
This morning I put the clutch together with the new plates, new soaked corks and even-deeper channels anyway; bunged it in just to keep the scooter whole while I have a think. Gave it a quick go and with a tweak of cable I got rid of the drag. I know I still need a new basket, but I’ve got no drag, I’ve got neutral when I need it and all gears select smoothly changing up and down. No judder, no snatching. Being very gentle 'cos of rivets, but it's all there.
I’m still not getting a new basket for a couple of weeks though, and I’ve made a big note concerning several adverse comments about cheap banded ones; undecided what more to spend on scooter, there's time to investigate and ponder.
Does anyone still think I should check my cush drive? Even without the progress this morning, I was thinking it was a big step backwards and a lot of work and expense on a hunch, especially as I reckon there’d be signs of that sort of problem on sides of channels too if it was snatching enough to loosen the pegs. Given all the other issues with the clutch, I doubt the pegs were OK to start with. I can do it, but maybe a bit of consideration of evidence first?
Anyway, thanks everyone; I'm done for a couple of weeks - I've overspent, and need a break from thinking about this all the time.

[vespasco]

Excellent
No drag! Yippee!
Im glad youve made progress.
As for your cush drive. It would have the next thing i checked/changed after the clutch itself, after your original clutch exploded
. Especially if it has been grabbing or dragging. Its a cheap relatively easy thing to do if your engine is split already.
When you get a new basket, see how it goes. If it still gives you similar problems then post back on here.
Bearing in mind what happened to the last clutch..... Im hoping your clutch basket / rivets were like that before you assembled the clutch. (I mean , i hope its not a symptom of something else (likely - primary drive))
But congrats. You now know how to rebuild a clutch
Good work
Enjoy your R n R

[joey]

Sime, I wouldn't be using that basket at all kid, if the rivets are that loose they're going to go very soon resulting in complete loss of drive and metal flying around your gearbox........ the latter being the biggy.
Not worth the risk fella.

[vespasco]

I agree with joey.

[sime66]

Me too, I’ll leave well alone now, ‘till I get a new one.
Cheers Chaps.

[henri]

hi, not read the thread for a few days ,but happy ya making progress an getting there , cant get a sense of how loose ya clutch rivets are from the thread ,but if it was me i'd probably tighten them up with a hammer an ride carefully whilst saving up for a new basket .without knowing how long theve been loose you cant know how far the rivets have been weakened,really loose ones an the basket/spring cups saw away at them where you cant see .have you thought about getting a local engineering shop to drill them out an replace them ,or even upgrade em with a tag-weld on each.am guessing that would be cheaper/quicker than saving/waiting on a sip banded/billet one .
i'm still of the opinion you shouldnt need to go banded/billet clutch unless your tuning more an riding like a hooligan , an with all the work done on that basket its a shame to waste it ,if ya cant find a local guy to do it post it to me an i will re-rivet an tag weld em aswell for the cost of the rivets an gas to get them hot ,a beer to cool me down afterwards wud be appreciated but not mandatory , henri

[sime66]

This might sound odd, but I’m actually quite happy; when it was a box of bits a couple of weeks ago I never really thought it would go again. Yesterday morning, once the clutch-drag and gear-changes were OK, before the warnings of impending rivet-redistribution doom if I kept riding as it is, I got a glimpse of it actually being all OK and fun to ride again. There are still problems and concerns, but it’s looking doable again to me, which is a good point to pause and ponder.
I’m sorry, but this is a bit long-winded, but it’s my thinking so far about this basket, so not strictly necessary to post, but I thought I’d share it; skip it if you like, but someone down-the-line might get something from it all.
I’ve got to start by coming clean; I am not actually skint, just aware that rash choices will be more wasted money, that the overall cost of this job is now a bit silly, and that I do have financial obligations other than my scooter, which is taking all my spare cash at present. I could buy a top-of-the range clutch now, but it would be foolish and unnecessary, so I’m putting it off until payday, when I’ve had time to investigate and make an informed decision. I may borrow from myself to do it sooner, but only if I’m dead sure of my decision – speed is not the prime-mover; a correct choice is.
The break from me and my flat being permanently grubby is another bonus, but I couldn’t put it out of my mind completely, so I have had a look into my options for a replacement basket. I’ve used the opinions on this forum, what I’ve read about the most common problems, my own experiences of clutch failures, and my ‘rational-head’ budget, to knock up a shortlist, and decide what I think I’m going to get; this morning I knocked up this bit of pondering/info gathering:

Cosa Clutch Basket Selection for lardy, middle-aged hooligan (say £50 - £100 budget)
Must have:
· Reinforced / Strengthened Basket Material (Can it still be filed easily though?)
· 16 Rivets
· Reinforced (wider SIP) circlip
Good to have:
· Welded rivets (8/16)
Unsure whether should have:
· Reinforcement Band
Must not have:
· Piaggio, Newfren, ?others? manufacturer.



So there’s only two links needed:

SIP (93401000)
www.sip-scootershop.com/en/products/clutch+basket+sip+standard+_93401000

SIP (93402000)
www.sip-scootershop.com/en/products/clutch+basket+sip+sport+cosa_93402000

Reasons for Selecting SIP (93401000) (Unbanded):
· Forum concern about banding – weakened/softened basket?
· Forum opinion – not needed anyway for my girly engine. (How girly is it in Hp?)
· Ease of installation – Extra width within casing possibly not allowed for when I was Dremelling anyway.
· Price
Reasons for Selecting Beedspeed (for a SIP basket):
· I’m p*shed off with SIP over last c**k-up and delay.
· Royal Mail within England, rather than UPS from Germany.
Reasons for NOT Selecting Beedspeed:
· Costs £81.99, and SIP costs £74.19 = £5.00 more (SFW)
· They haven’t replied to me today regarding stock.

Henri, you are a splendid fellow, and I reckon, given the labour of love already invested in this basket, a good repair, with new and tag welded rivets would be a much finer outcome for it than just ditching. I’ve seen the replacement rivets online, and I had thought about repair/replacing/getting a mate to weld, but I don’t know anyone who I’d trust to understand the need not to bend it up whilst welding, so I’d only really be happy with a mechanically-minded scooterist doing it. I already owe you, and others, several large, cold ones for the help already given, and I’d be delighted to cool, lubricate, remunerate you, and generally make it worth your while. I have now got my heart set on a 16 peg, hardened (not banded) basket though; purely because these do fail and twice the pegs is half the force. If you fancy a bash ‘because you can’, I’d still go for it and keep it spare, but it isn’t strictly necessary; I couldn't hand-on-heart say I'm delayed by saving-up.

Before I make a final decision, maybe this one repaired with new, welded pegs and the upgraded circlip would be a good, sufficient answer? (But that's an afterthought on this morning's choices).
I must confess, having read so much bad stuff about Cosa, I even thought about going back to a Mk1 with a Cosa conversion nut, but I think I’m over that temporary mind-aberration.

Slightly related: I might start a thread covering horsepower; I had a read-up on that this morning, and it left me slightly confused about the engine data Vs dyno graphs, but I’ll let that lie for a bit, see if I can suss more out myself first…..

Anyway, have a good weekend chaps, it’s going to be a beauty! Glad I’ve got one of those al fresco sheds!

[joey]

Have you got link for rivets........ when mine went silly I looked everywhere and couldn't find them.

[sime66]

www.sip-scootershop.com/en/products/rivet+clutch+basket+186x3mm+_23736500

If I find anything other than SIP, I'll post later.......

[henri]

good to hear ya getting the right perspective on this ,an not having "canal thoughts" again, would be happy to do ya old basket ,but postage back n forth will add up to more than you getting a local engineering shop to do it,they dont need to be scooter-friendly just competent ,sumthing i'm not often after "beer-oclock " which in "chez henri"is about now, 4-30-5,
but if funds allow i reckon a sip non-banded ,stripped n checked by you an put on right will give you more piece off mind an many happy miles hooliganizing the local villages/cows/tourists . an is also the straightest path to being back on ya scoot.will still do old 1 for ya but on the back burner as a spare for ya cuboard spares stash, just in case.
an joey the rivets are a standard metric size ,thank you piaggio gods, so you should be able to find em online by size or a local engineering/clutch/brake lining place might just have a box full sat around. as soon as sip put "vespa clutch" in front of "rivet" they magically change from £5.00 a 100 to £1.50 each , an thats tuetonic thoroughness for ya ,i havent got my little black book of "stuff i sometimes need to know" with me ,but i just measured by drill bit the hole an got 1's long enuff to trim down.
weird you having probs with sip postage,theve always been really good for me, have you been dropping buttons in the collection plate at church sime,he sees all an always gets even mate,hav a gud weekend,Henri

[sime66]

Yes, I really don’t want to be worrying about this clutch once it’s back in and set up right; reckon I’ll get the 93401000(basket) & 93182000(circlip) in time for next weekend, maybe catch some of this good weather, and think about repairing the wobbly one later if I can find rivets cheaper than £15 a set. I’ll have a better look after I’ve measured mine; do you know the hole diameter? Mine’s back in the engine, and staying there for now.
SIP are a lot cheaper for the basket, but they’ve just let me down – not sure. Don’t want to have the hump with them ‘cos they are normally excellent. I think they had a busy period, and picking, stock control and communications were all below par when I just did my engine build order. – Or maybe I did rub the vicar up the wrong way.
· Is it worth using 16 or springs?
· Just to tidy up the subject of spacers; what worked for me was my original 3mm(measured) non-autolube spacer, and a 0.8mm (SIP) spacer; this then makes up the autolube drive cog thickness of 3.8mm. That might be obvious to most, but aiming for 3.8mm, if you haven’t got autolube and can’t get your hands on a cheap cog, seemed to work. That might help anyone following later; obviously getting the channels right is crucial too.