Cosa ll clutch

[vespasco]

Finally something gave in on my pinasco motor.
Ive been trying my hardest to break it every time i ride it.
But luckily i was almost outside my home

A few weeks back i was coming home and changing up to 4th it then clunked into gear as if there were no clutch.
There was barely any tension on the cable.
But then when i had to change down again it was ok.

It did sound a bit odd too. A little rattly maybe?

I finally got round to inspecting it tonight
Heres what i found...

Ah. I cant post pics from my phone

Ill post them later

Keep you in suspense


*Edit: pics added
Of all the things to break its a tiny little rivet holding the clutch together

Attachments:

[sime66]

Diagnosis is pretty clear.
What you gonna do with it? Repair or replace? did you still have some questions?

After I'd looked into it before, I got:
16 rivets and springs, strengthened basket and reinforced circlip.

There's links to the basket, circlip AND just the rivets on the second page of previous thread here:

vespa.proboards.com/thread/4070/cosa-clutch-fine-adjustment?page=2

[vespasco]

Well, im hoping to repair. But that will depend on how good my rivetting skills are! Im not sure if im gonna need a bench press or if a larger hammer n block will suffice as yet. Anyone here actually re rivetted a cosa clutch??

Initial inspection shows very little/if any damage to the basket itself.
Its a nice hard one (fnarr!fnarr!) which makes me want to keep n repair it.
If the basket was soft n burred then id just by a new one.
The previous pic shows the only burr/wear on the basket and thats minimal.
The plates themselves are burred, as expected, but thankfully not the basket.
Comparing this basket to some of the other horrors ive seen i think mine is actually ok!

I may buy a few extra rivets and acommodate those too.
If i change them all one by one it should be ok
Maybe borrow a welder too?

Is there a reason these are rivetted and not welded to begin with? Or Is it the high carbon / different material that makes them virtually un weldable?

Im also wondering if i forgot to refill with gear oil when i serviced a few weeks back, as the clutch looks drier than expected. Which may explain why all this happened in the first place. Ill look tomorrow. It wouldnt suprise me.
Short term memory loss and all that

Its so tempting to strip it all down but i really want to carry on with my experiment and see which parts wear/break first.
In this case, after nearly 5000 miles of thrashing it hard, lots of long WOT riding, it was a clutch rivet that was the first thing to go. (Probably due to lack of oil, causing excessive friction etc etc)
Im confident that if the clutch was on a stock motor (with lots of oil)! It would still be fine.

I still want to find out how long my bearings n seals , cruxiform etc last so will not plan on changing those
until they break/wear or its too late.

Thanks for the links/tips
I knew youd be the guy to ask sime!!

[sime66]

Rivets do seem to be the weak link – Joey had rivets go, and I had that manky basket with loose rivets too. (Hence choice of 16).
I did notice on the pics that it looked very dry inside your clutch though.
I thought that the basket looked a bit spread too (from the circlip* in 2nd pic, which looks nearly out)
Henri described the method of riveting before (in his own colourful style):
“with the rivets ,the peg end is hardened by a magical/secret process i cant tell you coz i'd then hav to kill ya, nah not really,cant be bothered to type that much,an the rivet end is still "malleable" (soft) iron, an the peg is supported in a former,basically a bar with the right sized hole drilled up its axis , not a***x ,you rude-boys ,rivet end is given fast/feirce heat til tip is reddish,stuck through basket an hot end flattened over with a rivet-punch,a tool-steel punch with a shallow dip in end the shape ya want head to be ,all done faster than ya can read it an def faster than my 1 fat finger can type,then quickly quenched so heat doesnt take too much temper/hardness out of peg, bet ya wish ya hadnt asked now eh,”
My précis: [Fast/fierce heat – former – rounded rivet-punch – quench - repeat]
Then tag weld for extra grunt. (Not in my field of experience – yet)
Link for just the rivets (SIP, but if you find elsewhere, I’d like to know ‘cos still got one to repair too):
www.sip-scootershop.com/en/products/rivet+clutch+basket+186x3mm+_23736500
Must also recommend the *reinforced circlip (SIP again, but seen them about elsewhere):
www.sip-scootershop.com/en/products/clutch+basket+circlip+sip+_93182000
If you’ve never had one in your hands before, it has a reassuring stiffness to it. (fnarr fnarr back at ya!)

I cannot imagine why you’d want to break it deliberately – what I’d give for just a few weeks of riding mine and it not breaking! (Actually it is good now; what I’m doing now is just maintenance/MOT prep)

[vespasco]

yes its well dry in there
i checked my fuel level, no oil!! wtf!?
i thought id changed the oil not so long ago but looks like i forgot to refill??!! oh fk
User error
Im sure if there was enough oil that clutch would still be ok. 


Im going to trying the rivet repair method
Im going to get a few spares too.
Im only going to rivet it because the assembly is not loose. I think i caught it just in time before any major damage was caused.,
So, drill the rivets out, make a suitable block to help whack them in one x one, dull red tip, quench in OIL (not water)
and order some 3mm cobalt drills!

if thats how they make these rivets then its gonna be the weak link for sure

maybe those old style clutches are not so bad after all!

ive cleaned it all up. Just a few slight marks where the clutch plate tongs have been whacking the basket. No other noticeable damage


the basket has not spread, its just the picture makes it appear that way. I had to look twice! the large circlip looks as if its spun around at some point. I also notice how soft the circlip is by the imprints of the clutch plate almost moulding itself to the softer circlip.
i will defo get one of those reinforced circlip.


as for breaking it deliberately, its an experiment,....
how long can a pinasco (my 225) be ridden @ WOT, everywhere (where possible)! accelerate hard in every gear (wherever possible)!?
Ive found the weakest link - ME
If had put oil in it it would still be ok!
So,
sadly,
in conclusion,
My vespa is more reliable than I am !

I'll keep you posted on the rivets when they arrive... 

do you want me to order extra sime?

[sime66]

No oil eh, I’m saying nothing.
I think the pegs are riveted to keep the basket from the heating/cooling/…… of welding, aren't they? (Which is why I decided against banding). But it’s definitely a weak point anyway.
If I started from scratch again, I’d probably be inclined to use a Mk1 clutch with the Cosa nut conversion.
Having said that my Cosa is yet to disappoint; it’s just that I don’t feel like whacking it like I did before my clutch aggro, - which was a Mk1, so I may yet revise that opinion.
If you’re buying from SIP I don’t think I’ll get any rivets at the moment – best part of £20 for something I might not use is not sensible; I’ll hang on in the hope of a cheaper source.
Thanks for offer though.

I’m off out to try to get cables through my forks; happy days………

[vespasco]

Yes no oil. I figured out how that happened. A few weeks ago i went to change the oil as part of routine maintenance. Drained it. Had a cup of tea. Realised i didnt have any gear oil. Got distracted. Left it. Went out on it a week or so later and totally forgot to add some more oil!
Doh!!

So now ive ordered a BGM superstrong clutch, a bit more than the sip. ££££ Gulp. But figure that should be good for life!!?

blog.scooter-center.com/en/bgm-pro-clutch-for-vespa-px/

I will fit another rivet/maybe more rivets to the otherwise ok cosa basket and keep as spare, depending on how confident i am of a good repair. Im quietly confident it will be fine as Ive studied and worked as a welder/engineer. So long as its used with oil in the gearbox it will be fine!!!!?

I saw a welded Beedspeed clutch with the band just tacked on. Im not sure which was worse, too little or too much weld!!?

BGM will be (hopefully) fitted at the weekend.



Have you got any tips Henri? On riveting the clutch?

[vespaskin86]

hi vespasco have you got the bgm clutch installed yet and how have you been finding it? also did you have to modify the clutch cover as suggested if so was it easy? sorry for the lots of questions its just ive been looking at these for a while

[vespasco]

The clutch cover is a very easy mod. to do.
I think the instructions are on the link above.
I actually used a 4" grinder with a worn disc (so it was small enough to fit in the cover) but a dremel would be.perfect. Its very easy.

But heres what happened.....
I installed the clutch, re filled with oil! Everything looked normal inside the engine.
Tried it without the motor running. It was definitely a little stiffer (with the supplier 'L' rated springs) but that was expected.
Started it. Ok. Then I heard a pop. I turned it off quickly. Scratched my head.
Looked at it. Nothing.obvious. Dared to start it again.
Again same thing. A big 'Pffffffff'.
Decided to strip the fecker down to have a closer look.
My crank was floating in oil. Both seals were blown. And the Pfffffff was coming from the head!!
Maybe I did actually.fill.up with oil but the cylinder just drank it all?'?!?


The clutch is fine and it really is a lovely piece of well designed and made kit.
Ive.not.had any miles on as yet though!


I also discovered ive done over 6000miles on this motor. I forgot to add on the miles when the old speedo was fitted!
So actually im pretty happy with how its been upto now.

Sip delivered my parcel of bearings seals crux etc today so tomorrow Im hoping to get it all back together during/for the bank holiday!?!?

The bgm was a tight fit too! And comes with new nut, o ring and woodruff key. Plug n play!? Maybe a simple clutch cover adjustment required?!

[vespasco]

Update:

Ive got the engine back together over the past few nights. It started 2nd kick!! TFFT!! I took it out for a ride , first up and down the road where i live, then around town, close to home using the clutch lots.
Well, the new BGM clutch. Wow. Maybe its because my old cosa ll was on its way out but the BGM is really ultra smooth. A little harder than a stock cosa ll clutch but thats because the springs are stronger (rated at 'L') and theres 10 of 'em! Not 8! . Its a real joy to use. I barely gave it any throttle and released the clutch slowly and it was perfect! Then lots of throttle and released clutch slowly, again perfect!! I imagined this is how a big modern bike must feel!?
Its a little deeper than a stock clutch and as such there is not so much play on the clutch arm as before. Its not a problem but i guess thats why you need to trim out the stiffeners inside the clutch cover as per BGMs instructions. Thats all you need to do. Real easy tho'.

It was pulling at a constant 24mph in 4th gear with no 4 stroking! Very smooth!( But later it did! at around 30mph in 4th!)!
Rode it for an hour. Going no faster than 50mph (approx 1/4 throttle). It still needs a fine tune but it was getting cold in just a T shirt n flip flops! (Yes and trousers and helmet)!
Scoot is parked up now so Ill check the floor for any leaks tomorrow. Re torque a few nuts. Then warm it up, fine tune it, and ride it for a couple of hours /100 miles , slowly taking it up to top speed. Plug chop. Adjust as necessary. Then we'll really see if its 'in tune' So long as it still does 70mph without pre igniting i'll be happy. Ill find that out at 3/4 throttle in 3rd. If it doesnt pink there, then i know im safe!
Im gonna be taking my AA card with me!!

Heres what i've been upto:
I spent most of my time cleaning all the crap/dirt/grease off the bolts and gasket surfaces etc more than anything else!
I fitted all new bearings and seals, piston rings, and even treated myself to a new spark plug (B8 EVX - iridium)

The amount of wear after 6000 miles of me give it a damn good n hard thrashing. (Actually i bought the kit off ebay, with apparently no more than 1000km on it so almost 7000miles);
The bottom ring gap was 0.58mm.
The top one 0.28mm
Im not sure of Pinascos tolerances but for comparison the ali T5 cylinder is 0.20 - 0.4mm (lower ring) and
0.2 - 0.35 (upper Dykes ring)
and the stock cast iron 200 is 0.25 -0.40.
My new Pinasco rings are: upper - 0.20,
Lower 0.23 so i made no adjustments.
For comparison, my stock px200 engine had a ring gap of 0.6mm! after 10,000 miles.

I also lapped the carb base, cylinder and head.
Welded the crack in the cases, cleaned carb,
Covered most screws bolts n nuts in copper grease, especially the exhaust bolt and the long engine case bolt underneath the cylinder. I find these 2 bolts are always the worst 2 to get out. Grease is the word.
Re shimmed the gears. They were 0.15mm when i first built the engine. 6000miles later -0.35mm. Now 0.25mm as i didnt have any other shims to make it 0.15mm
Cruciform was still in good usable condition so i turned it round and reused it.
The gears and shaft and selector were also in excellent condition so were reused.
Whats interesting is that ive discovered my drive gear is actually made by and stamped 'TDH' , which is an Indian manufacturer. I have to say the quality is excellent. Id even say the TDH cruciform is actually harder wearing than an original Piaggio! Thats why i reused the TDH one and not the brand new spare Piaggio one i have.
I also noticed my sip road (mkl) has a tiny dent (or a hot spot, i could not tell because of the rust)! So that may need replacing / welding soon. If i have a good spell of work this month i may just treat myself to a mkll and the extra hp it gives out.

Now the real test is racing National Express buses down a motorway!! Maybe at the weekend?!

Ill let you know how i get on.

[sime66]

Good job, well done. Made a good educational read too.

[vespaskin86]

might treat my self to early birthday/christmas pressi

[vespasco]

Sept 2, 2014 21:26:10 GMT vespaskin86 said:

might treat my self to early birthday/c*******s pressi

Thats better.

Time will tell. It sounded so sweet when the main jet stack kicked in at just after 1/4 throttle. But not as responsive as i seem to remember it was. Hopefully, re torquing, then fine tuning the timing and mix screw will sort that out. If not, then im gonna be tinkering!

[vespaskin86]

oh dear i'd be out of my depth there i was hoping a little dremil work slot the clutch in and play lol my stock clutch isn't ideal for my engine set up and the way i like to ride. i dont know nowt about timing or retorquing but the mix screw i do so much to learn about scooters and engines

[henri]

vespaco, you mention welding ya sip exhaust , always a fun job , 1 theres packing/sound absorbing stuff in sip roads unless its the chrome 1's ,its fire resistant/proof but the carbon n 2stroke oil its soaked isnt ,so ya might have to drown it in water an dry it out afterwards ,good excuse to caustic soda it an get it unchoked at same time,but some packing will be lost so noise will be louder/tinnyer
2 , fumes from welding exhausts are 3-4 times more deadly than usual fumes from welding, cancerous hydro-carbons,liberated sulphuric acid from exhaust deposits, chromiun fumes if chromed ,zinc ague (like flu but worse) if its zinc plated/painted. an much much more .
3, exhausts rot from inside,sulphur in oil makes acid with water from combustion, so what looks like a pinhole from outside will prob be a 1p/2p size inside , ive managed to save really rare n rotten unreplaceable exhausts before by re-skinning with thin st/steel baking trays from my favourite 99p store, an ya have to weld em by joined up spot/tag welds ,takes a lot longer as youve to wait for it to cool but on really thin/rotten metal it will give penetration an a continous leak free weld with a lot less distortion , a reactive mask is well handy as a flip up 1 will give ya whiplash/achey neck .
i'm not saying dont try it ,just well ventilated for you,shielded from draughts for the work an slowly , an afterwards you be able to weld wet kleenex to cast iron , simples , H

[vespasco]

Thanks henri. Thats jogged my memory!
I dont weld now, although it was my job for many a year, i gave it up after studying it for 3 years, the more i learnt the more i thought.... 'F this and all the deadly fumes im breathing in' and quit. Glad i did too!
But I cant remember half the stuff i learnt now!
My old SS180 exhaust was virtually all weld at one point!!