Clutch explosion

Hello everybody,

My clutch basket and everything around has just explode, I have the renforced cosa clutch basket art.: 93242000, what do I have to buy with it as it doesn’t seem to have a complete kit for my PX150 on SIP.

What do I have to order as it’s not clear at all to me!!!


I say it once again, clearly and loud, for the newbies :

" This guy is the best, no way to say anything, I think the only thing that he don’t know about Vespas is the color of mine!!!"



I have the original christmas tree from the PX150 with the Malossi upgear kit.

You said some weeks ago „I would change your gear ratio to something shorter since we will get the speed with the high rpm the malossi 1666 is capable of.
I would use a renforced cosa clutch basket with 21 teeth and 65 primary drive from PX 200.“

Do I use the same art number you said?

Here is my setup :

  • PX150
  • Malossi 166cc
  • SIP Performance exhaust
  • Dell’orto PHBH30
  • Reed valves Malossi¨
  • Airfilter Ramair
  • Cylinder and the casings are ported together
  • Dell’Orto Fuel pump

Yes I guess I have everything now but it sounds like I’m gonna leave some euros there, I really don’t know what to do!

I have the week-end to think about it and order sunday night.

Any other advice welcome!!!

Max, have a nice week-end!!


Curare, I’m thinking of a thing, is the output shaft the same if I mount a PX200 christmas tree?
Do I have to change the clutch cover?

I think I’m gonna leave my PX150 clutch but with a 21 cogs and the 65 of a PX200.

So I need :

  • Clutch plate reinforced : 93220000
  • Clutch gear 21 cogs : 17800000
  • Primary 65 PX200 : 11272000
  • repair kit :1602000
  • Friction plates : 93050000


Do I have to modify something if I buy all the Cosa clutch parts or is it „plug and play, or plug and ride“, just fit the cosa clutch instead of the PX one.

Is the complete cosa clutch N°93031000?

Can I mount a 21x65 on a conventionnal PX 150 Clutch in a renforced basket (art n°93220000)?

It seems that there is no 65 for a PX150 does the 200 one fits ok without any modification?

Do you have something of these in second hand?

How is your knee?


Sorry curare/mikkke to but in!
if you orignaly had the px125/150 five spring clutch, you would have to remove some casting from the clutch cover and a small piece from the engincase,easy!
And if your not going for cosa clutch, go for the old p200/t5 clutch ‚reinforced‘ (8spring) they still break! but not as often as the 5 spring!

hello Mikkke,

I am not sure I understood it well.
Did you explode the renforced cosa clutch or the normal clutch?
Or you exploded the normal clutch and you already have a renforced cosa clutch basket that you want to install but you are missing some parts?

…if you had a normal no cosa clutch before you can’t change its basket with the cosa basket.
You will need to buy:
-renforced cosa spring art :93120000
-4 plates cosa clutch art.: 93080000

-cosa clutch primary gear (either 21 cogs or 23 cogs depends wich gear ratio you want and wich christmas three you have. If you have the PX200 christmas three you can use both if you have the one with 68 teeth you can go at the most to the 21 cogs)
here you have the art. number for both:
Cosa primary gear 21 cogs art.: 87470000
23 cogs art.: 87460000

Cosa clutch base plate incl. bushing art.: 15985400
…and should be it…

…I was forgetting the circlip for the cosa basket to firm the frictcion clutch plates

yes you could buy the complete cosa clutch already with the renforced ring art: 93031000.

When you have the complete cosa clutch it is not in your case a plug thing since you have told me you have the malossi upgear kit. This means, as I told you in my previous answer that you have changed the primary gear in your input shaft (christmas three) and now you have a malossi with 64 teeth that are straight. The cosa cluch use elicoidal teeth so you can’t mount it unless you change the primary drive of your christmas three or change directly the christmas three with a PX200 one.

Yes you can mount 21X65 on a conventional PX150 clutch in the reinforced basket (art:93220000), but you need to change your clutch gear with art:17800000 and again you have to change the malossi primary gear on your christmas three with a PX200 one.
Watever you are going to do you have to change the malossi primary gear on your christmas three or change the complete christmas three with a PX200.

In case you want to change just the primary gear in your PX150 christmas three (imput shaft), yes you can mount the PX200 but you would need to take the malossi one out and fit the PX200 with a rivetting job if you know how to do it.

It is definetly easier to change the complete imput shaft (christmas three) with a PX200 one, then yes you can fit the complete renforced cosa clutch art 93031000 and enjoy it.

tank you my knee is slowly getting better.

For the moment unfortunately I dont have any of these items that you need second hand.

Now I really think you have all the options…

if you have the malossi upgear kit you should have either the 23/64 or the 24/63, but is more probable you have the 23/64 since the 24/63 is the longest upgear available.
The problem is that you can’t use the cosa clutch even if you are going to stay with the same ratio (23/64) since the malossi primary you rivetted on you christmas three (imput shaft) has straight teeth while the cosa clutch teeth (cogs) are elicoidal.

So you have two option:

  1. forget the renforced cosa clutch basket you already have and buy a no-cosa (old PX) renforced basket that you could use with the other parts you have

  2. keep the cosa basket, buy all the things you need to complete it and either
    -buy a PX200 primary drive (art: 11272000) with the repair kit (art:16020000) to do the rivetting job to fit in your imput shaft (christmas three)
    -or easier but more expensive buy directly a complete PX200 input shaft (christmas three) art:88220000

If you choose the first option you will stay with your for me too long gear ratio.

If you choose the second option, way more expansive, buy with all the article to complete the cosa clutch the 21 cogs(which art numb. I gave you in the previous mail), so you will get the 21/65 gear ratio that I am sure will work much better with your set up.

I hope this help.


yes thank you for your answer Slidingdog.

Yes Mikkke, as Slindgdog says if you put the cosa clutch and now your engine has a 5 spring clutch, you have to take some small part of alu from the case, it is about at 2 o’clock position, you would realize wich part is since becouse when you fit the clutch and will try to turn by hand you will realize something block it in a certain position. But is a very easy job 2 min with a dremmel.
Then check also the clutch cover.

If you opt for the older style clutch listen to slidingdog suggestion. And buy with it some renforced spring too.

Your output shaft is ok with PX200 christmas three.
The cluch cover would need some minor mod. if you use the cosa clutch.

Have a nice week-end you too.

Yes that’s it : I exploded the normal clutch and I already have a renforced cosa clutch basket that I want to install but some parts are missing.