Modern Vespa

I bought a Pinasco 225 Supersport kit and a 60mm crank by the same manufacturer to fit on my P2 when the kit came out 4 years ago. The idea was to run a slighly more powerful but still reliable cylinder on my daily bike. Although the "adapting" was a bitch (cylinder exhaust stud too thick for any of my exhaust pipes, seals blowing because compression too high, spark plugs loose because thread in head a bit off, slots in crank too narrow for most woodruff keys, etc.), once sorted out, it was a nice and torquey kit with the benefit of keeping an SI type carb, rotary induction, and autolube.
But at little under 2500 miles, with no warning signs, the bottom half of the piston broke (under the pin).
I should mention that the kit was in no way abused during its short life: just zipping around town and half-hour freeway runs mostly.





I would have cast this off as an annoying but freak incident, had it not been that a friend in the neighborhood broke the same piston in the same manner twice in the same period:





I've been running Polini and Malossi kits on both T5s and P2s for years, with the occasional predictable heat seize, but never have I experienced a newish piston breaking under no stress at all. Most Pinasco veterans had told me these kits (well, the previous ones actually) were made to be thrashed all day.

So I was wondering: has anyone else experienced this kind of trouble with pistons from the 225 kit breaking in this unexpected way? Just wondering if there's a pattern....

Who makes the piston?

I don't know anyone running one of those but it used to be a fairly common occurance with the Polini 207 using the single ring Asso piston.

Asso, like every other (durable) kit I've owned.
I've cleaned up the engine and barrel (there was little piston shrapnel everywhere) and ordered a new piston, and noticed they have made changes to the rings and the shape of the pin clips; there's no indication that other changes have been made...

How close is the piston skirt to the casing at bdc?

The crank is a Pinasco long stroke (60mm), which means the clearance compared to the regular 57 should be asumed to be sufficient. I couldn't quantify the clearance exactly, but during installation I did check that it wasn't too close to the crankcase as a natter of routine (it wasn't)

Ok, cool - I know with the wideframe Pinasco kits the piston skirt needs shortening when fitting a longstroke crank to clear the casings.

Maybe double check the clearance - there's a certain about of conrod "stretch" at high rpm too and there's a minimum clearance measurement to allow for this (sorry I can't remember what it is off the top of my head).

In all likelihood it's not this but at least you can rule it out.

Thanks,
Rog

Are you surprised? I am not,.. Pinasco makes garbage. I had a pinasco 210 kit on my P200E and it seized half a dozen times until one time I was just riding at 50 mph and the whole kit crumble like blue cheese. "nickasil" cylinder liner crap.

I threw the kit on the trash and I swear I would never buy pinasco ever again. I had malossi and polini and they are far better, never had any issues and I ran the scooters hard.

That's a very one sided view. My Pinasco SuperSport 225 has been all over the place, often at high speed, often with a pillion, sometimes with luggage, in scorching heat and up gruelling hills since I installed it in 2013. It's had a new set of rings and probably needs another set soon, but it's been absolutely rock solid.

The OP was probably unlucky with that piston. When I rebuilt my motor last autumn, the piston looked almost brand new, after at least 6000 miles of touring, commuting and spirited local use.

Unlucky but sounds like you got away with it. These big window pistons never were the strongest but this wasn't just a failure.
Issue can only be one of these three.
The piston windows have not been chamfered at all (should be done inside and out).
Might not be enough skirt to crank web clearance for a 60mm crank (the Malossi Asso needed 2mm cut off the skirt to clear).
May have been cracked before installing.

Was running rich by the looks of it, so little chance of a seize up. Wonder what the piston crown looked like.

Yes! Not me but one I put together for a mate. Did around 20,000 km as a daily rider until this happened. I put it down to a CDI without an earth. (I had had several minor seizes and finally a shattered cylinder skirt on my old Polini 208. I had tried to work out what was going on until finally put a timing gun on it, and after about 4000 the timing would swing as much as 20 degrees either way.)
Anyway maybe I was wrong about that bit? Would love to know the real reason.

I just came across these pics on an Italian FB page. They said "Revision 162 pinasco in +o-1600 km we opened to edit the 4TH AND SURPRISE 2 fissure on the piston". It's from a T5 kit. The guy says this is the third! piston it has happened to. I know it's not the 225, and the piston design is different, but it may say something about Pinasco.
There were a number of comments about Pinasco denying any problem... my favourite "If you talk to them maybe they answer you that the continuing to work with two important cracks, is a symptom of extreme reliability and quality of materials."

https://www.facebook.com/groups/151068948953942/permalink/308299473230888/

Saw that too. Don't know what to think anymore. Problems with their cases, cracked pistons, wrongly machined crank webs. Maybe FMP has a reason why he doesn't like them...

I'll say this about that FMP fella -- I've met him a couple times in Vienna, and he's the real deal. He wades through all the bunk and mythology of various 3rd party parts suppliers by way of measuring things and gathering data. And when he gets things wrong, he admits it. Also notable is how he doesn't pan all stuff from any particular manufacturer, based on little evidence -- he'll cheerfully say that product A from a supplier is excellent, whereas their product B is crap. But maybe product B was better from production years x till y, before they moved to -- yadda yadda yadda, you get the idea.

Anyway, we need more nerds like that guy. Listen to him!

Thanks for chiming in Sean! Not sure about in the flesh, but all the emails I've had with him back and forth... he's as stubborn as he is knowledgable!

Pinasco's rotary T5 kit has to be the stupidest thing I've seen in recent memory.

hi frank. condolences. bad story! but the asso piston is known for breaking.
with the new pistons for the t9 225, vespone etc. its even worse, they break even faster.


Question:
Can i pls use the picture of the broken asso piston on my FMP fb page?


there is one simple rule: never do pinasco (samesame for bgm btw)
this saves money, time and nerves. They do lack a basic common technical sense. (or they just dont give a sh...)

of course all complaints are answered with: assembling mistake by costumer!
Also with the engine cases s where bearings and bolts can get loose within 2000km, the guess here is that the cast iron is of low quality, once it gets hot stuff gets loose.


the asso piston is a very old piston from the 80ies, when the 200cc vespa was new they copied the original 1 port cylinder into alu with 213cc, also only 1 real port. since 2012 there is the alu polini. So they just renamed it to "SUPER SPORT" aha. sure it is!! race cylinder dont need real ports


Sport (2014) as best touring kit currently vs pinasco 213 (1979) "super sport" otuned so that you can see the port sizes
same price sadly or pinasco even more expensive
one definitely state of the art, the other one clearlly NOT


polini and pinasco use the old 80ies asso piston
even polini did NOT update the 210 aluminium propperly
its a 1:1 copy of the cast iron 207 sadly

= both, polini and pinasco are outdated.
avoid both.

seems like you havent seen the new t9 piston, voila:

https://www.lambretta-teile.de/media/image/product/44996/lg/zylinderkit-225ccm-pinasco-60mm-hub-vespa-160-gs-180-ss~5.jpg

&this kit costs 679,-


interesting how you can you can order and sell such a piston
(asian piston it is)

these 2 tiny cross beams will definitely crack

interestingly they also sell the new t9 with the old asso piston
https://www.lambretta-teile.de/Zylinderkit-225ccm-Pinasco-Race-9TX-60mm-Vespa-PX200

so 2 type of pistons
both weak.



have a look at that tiny thin cross beam, isnt it cute
http://www.pinasco.com/racing/it/vespa-rally-200-ducati/2057-kit-diam-690-957-rr-master-corsa-57.html?search_query=&results=173

but wait its even worse
on the other side the pin eye is also not connected to the skirt



http://www.pinasco.com/racing/it/vespa-rally-200-ducati/2128-pistone-completo-vespa-215-pinasco-9t-o-69-2-segmenti.html?search_query=&results=173


polini asso piston does have smaller windows
https://www.sip-scootershop.com/wwimages/bf283a8c-0e6d-457e-b434-bc35012ee4cc.jpg

pinasco made all windows bigger = the piston even weaker
https://www.sip-scootershop.com/wwimages/508aa37a-ac58-4963-ae42-d4f3fdc12a3e.jpg
https://www.lambretta-teile.de/media/image/product/40426/lg/zylinderkit-215ccm-r69mm-pinasco-race-9ts-8p-57mm-hub-alluminium-vespa-px200~4.jpg

I have to be honest, I haven't really looked too hard at the various pistons they use until now.

What I was really referring to was the lack of fins on the barrel and that bloody stupid stopper plate. WTF are they thinking? It's not like they couldn't do a properly cooled and finned rotary version as I was a big fan of the version they had out in the mid 80's to early 90's

guess there is a simple explanation:
they dont have engineers, cause there is obiously a lot of common technical sense missing.

they just have marketing and sales guys
the use what comes cheap and makes profit
but this time with a lot of cylinder kits with breaking pistons
aprox 5 kits, of course very expensive

they overdid it and it will damage the brand.



Frank
could you take 1,2, more pictures for me?
1 from the cylinder area if side ports with that wide edge
1 from the broken skirt or the part which ran exactly in this position


i have a theory why it broke:
it is the supersport with the widened fake transferport isnt it?
so there is a wide edge the bottom piston skirt always bumps in
the asso pisto skirt edge is pretty

as the piston is weak in general
and weaker cause the silly ones did make the windows bigger
it might be the cause that it broke

Hey FreakMP - I appreciate the info you've put together on the different performance cylinders and pistons!

If I hear you correctly, Malossi is much better designed and built (cylinder and piston) than Polini, Pinasco and BGM, correct? I'm not the sharpest tool in the shed...

Hi everybody, sorry I was away, but I wasn't getting notifications for new posts, so I thought the topic had died down on its own volition.

@FMP: be my guest to any images posted here (by me, in any case); if it can help raise awareness and maybe get Pinasco to get off their asses and look into their engineering, it'll really be worth it.

I'll have to look into the few pics I took when disassembling the engine, but be aware that most of the skirt was turned to pebbles when it crumbled. I'll probably take some more pics when I go back to check on the piston. I can't say I'm totally confident. I'm still running in the new setup (new piston, cleaned up cylinder, new bearings and seals as a matter of principle), with a projected running in time of 1000km before I actually think about twisting the throttle full blast on the freeway. Right now it seems comfortable at around 100kph, but I never keep it full throttle at that speed.

hi frank, thx for allowing me to use the pictures, yes it is my goal to raise awareness. made 2 videos the last days to help with the breaking piston problem.

starting with this, showing 28 different pistons:
https://www.youtube.com/watch?v=37lFfkSiPSA
weak asso piston:
https://www.youtube.com/watch?v=02OM88achRY

2come
asso piston trick, rounding edges:
pinasco piston history and weakness:


i do have a "sorry BUT" for you regarding your new piston:

rings: running it with coated aluminium cylinders is 20km long and should be done very HARD
piston: going slow for 1000km will NOT prevent the new piston from breaking. thats just a guess, based on my experience. why?
1) its the same piston and its very weak. its the worst 200cc piston
2) its still the same cylinder...

so if both parts are the same, would will most likely happen?
the same.

3) i dont know cracking pistons. never cracked one of these asso pistons.
why is that? i round cylinder port edges and the piston skirt edge.
this pinasco 213 ist 14 years old from 2004:
https://www.youtube.com/watch?v=U4vxifGOyyk

my recommendations:

a) take the piston out, rework the skirt edge and the transfer port edge

or
b)
you should take a GS 69mm piston, then you are good
but the super sport 1port (sry, its just a 1port) is not worth it
its a very old cylinder, only pinasco marketing made a "super sport" out of it
but its clearlly NOT


but the BEST option:
c) get rid of the kit, its outdated for many years.
you will always find a pinasco fan, trust me

buy a malossi sport 210, its even cheaper and definitely the best cylinder for touring with the best piston. malossi piston never break. and no u you dont even need to adjust the engine case. simple pnp with a standard box = 17hp at the wheel

malossi state of the art 2018 vs 1980ies pinasco 213 with only 1 real port
just a small difference, isnt it
but the pinasco is often more expensive
https://youtu.be/qMpMdMkkxYQ


malossi sport vs the also outdated polini 210 which uses the same weak asso piston (but with smaller windows, where the inner brackets still exists)
https://www.youtube.com/watch?v=qHReowAnB7M

Hi, thanks for your detailed comments.

I took it very easy while running in the kit the first time around because the tolerances were VERY tight, and a guy I know who races these in France had advised me to take an extra long time with this particular kit. As mentioned, the exhaust stud had to be reworked to fit into my SIP road (the original Piaggio pipes were just as tight so it wasn't the Sip), and the cylinder had to be raised to clear the ports, even though the rod was aleady a 60mm!! I'm running in the new piston for the sake of the ball bearings, and also because it doesn't feel at ease yet at high revs.

Concerning the ports in the cylinder, they were chamfered the first time around, and I insisted on the new piston as well. Really hoping that does the trick.

I forgot to mention that the cylinder skirt had cracked in the process as well:





So I tore down the bridge and rounded off the edges:

What was left of the piston:







The rod either got really hot, or the tanned by the blowdown?

The new replacement piston:

I had a crack on my Polini 208 cylinder skirt as well, and also cut it down like you did. It seized shortly afterwards. The guy that did the cylinder boring said that the skirt would have 'sprung' after cutting it... so basically at the bottom end it was out of round. Not too late to check that is it?

The Polini 208 is cast iron; the Pinasco alloy. Hopefully that will give me a different outcome A guy I know had a similar crack on the bridge of the skirt of his Pinasco 177, and he opened it up likewise - no issues yet, and it's his daily driver. I'll knock on wood (and pull it apart soon to check for clearances and the general state). If it does seize however, this will have been my first and last Pinasco...

Hope you're right and it holds out. Might be worth checking clearances though?

I assume you chamfered the new piston on the inside of the port windows too? This gives it the best chance of not cracking.

Cut cylinder skirt should be ok. You'll know as soon as it starts.

Setting the base packer to line up the port window bottom edges at BDC is not the most important. Where the top edge is sets the open duration and this the critical measurement.

Good luck. I think you got away with it.

"and the cylinder had to be raised to clear the ports, even though the rod was aleady a 60mm!! "

consider:
a) this kit is very old, its just a copy of the original piaggio 198cc kit
therefore only 1 real port
b) for setting timings pls measure them in details
just raising the cylinder is not the best way, as u lower the blowdown
which costs

thats the explanation behind why 57mm stroke setups do run better than expensive 60mm longstroke, cause the timings get rubbish with 60mm if u just raise the cylinder.

running in a coated cylinder = just a few kilometers
and HARD
read more about it from the motoman, a real proffessional
http://www.mototuneusa.com/break_in_secrets.htm

how you do it with a vespa, i showed here:
https://www.youtube.com/watch?v=Us9uLea7VSE


cylinder foot skirt broken
as it is just a small part its fine
just cut it out

my old vertex had the same problem, mom, i showed it somewhere..
here it is:https://youtu.be/qMpMdMkkxYQ?t=309

shart port edges, see your 2nd picture, this edge is also way too sharp,



"The Polini 208 is cast iron; the Pinasco alloy. Hopefully that will give me a different outcome"

not regarding the breaking piston problem
the material is not really interesting here
the port edges are


big differences between
pinasco 213, pinasco 213 L, polini 208/210

polini: the cylinderfoot window is U shaped at the very bottom
pinasco 213: just one real port, and small ports in general
pinasco 213L: in the middle of the runnig surface there
is an extremly wide edge on boths sided, piston downwards movement rushes into the weak sharp edged piston shirt, which most probably
slowly kills the weak piston

"I assume you chamfered the new piston on the inside of the port windows too? This gives it the best chance of not cracking."

1) round the piston skirt
2) massively round that silly wide port edge
sandpaper roll and flapwheel

so, i will now try upload pictures here to show you what i mean

as said, asso is the worst of all 200cc pistons, a beam is missing and pinasco knew better, they weakened it even more as they made the windows bigger and due to that the interrupted the inner window beams
here: https://youtu.be/02OM88achRY?t=84





(how do you directly post the uploaded pictures?)


thats a otuned 213 without the L shaped extension, u see how small the port is, the edge in the cylinderfoot (not visible on this pic) is not wide



now a bit coloured:



green is the area with the normal pinasco 213, that hits
the cylinder foot window edge, so a pretty small area

red is the new L shape towards the boost port

blue is the WAY BIGGER area the weak piston skirt now hits a sharp edge


red cross and arrow: piston skirts always hits the whole edge
red circle: ususally ports openings are interruped to protect the piston rings






now think of a piston ring, what would happen
my guess is that similiar things happen to the piston skirt
it always hits the edge a bit


now see where the piston hits the looong edge without a beam as transferports selfexplaining ususally have (i think i mixed one side up, but doesnt matter)




and if we look at your broken piston skirt frank
these marks might be what i was looking for
weak skirt hits the stupid wide port edge till skirt breaks



my recommendations for the pinasco 213 L shaped fake port in combination with the weak asso piston:

1) round the whole piston skirt edge



2) round all edges of the stupid wide fake transfer ports



and then hope the piston will last...

everybody else: please buy a proper piston the 69mm GS
u see: it has 4 beams as needed, the pin eye is not "unattached" to the piston skirt on one side (asso piston problem)

https://www.grand-sport.de/Kolben-GRAND-SPORT-MALOSSI-210-685mm-und-6900mm



but better simply dont use the very old piansco 213
its not state of the art
(sry frank!)


why is polini 207/210/221 not affected by this problem?
a) the piston is a bit stronger, the inner window beams still work
(as the windows were not extended)
https://youtu.be/02OM88achRY?t=84

b) cylinder foot window edge is U shaped
https://youtu.be/LRUv0ckoP54?t=143

c) port windows to have an "interruption" a beam in the middle
(otherwise the rings would break, or as said.. the piston skirt of a weak piston)







btw, your brown piston skirt is proof that you
were breaking it the soft way
if u do it the hard way, there is no brown piston skirt
as the rings tigthen perfectly

btw no L piston ring finally!
BUT it doesnt help that the piston itself is still rubbish....

=========================================

SORRY for double pictures, i dont know how i can add them into the post directly after uploading...

That makes a lot of sense that the extra wide transfers would be an issue. I have to say that I dismissed the reservation, thinking that Pinasco had likely considered the issue, and engineered the danger out somehow. Apparently not. The good news is that the rings don't actually hit the wide edges as their travel stops short of that zone (the largest being the exhaust port); but the piston skirt does.

The reason I raised the barrel was that even though the kit was supposedly made for 60mm crankshafts, the piston failed to clear the transfers when at BDC:



Today I opened up the top end to check clearances and do a bit more chamfering, which I knew had been done lightly the first time around.
So I chamfered both the piston skirt AND the bottom edge of the L ports, and ran the piston slowly past the ports while pressing on either side without the rings on, to check if there was any catching on the edges, but with some extra chamfering, there was none. I get that once the engine heats up the play will be enhanced, but then the rings will somewhat take up that extra play. I didn't go all the way to actually "rounding" the edges, but the sharpness is gone, and everything is now smooth and blunt.

This is what I saw as I did apart the top end:

Rather sticky combustion chamber (the black matter outside of the sealing zone isn"t leakage: it's just stretches of Reinzosil sealing compound which happens to be black):



Strange carbon deposits, with actual bare metal zones:





No excessive scores on piston or cylinder walls.

What the rings have to deal with:

[img]https://i.imgur.com/NN4Dr8t.jpg [/img]

What the piston skirt has to deal with:



As mentioned, the bottom part of the L shaped port and the piston bottom edge were particularly paid attention to, and I'm somewhat confident (hopeful) that they won't be banging into each other. Whether the piston falls apart on its own is a different story. In any case, I tried to make all edges as smooth as possible inside & out without actually removing too much material...

Oh, and I should mention the clearance at the bottom between piston and crankcase: I could see there was some space, but it was hard to quantify. So I took some 2mm soldering tin, and placed it in a way the piston would have to crush it slightly it it came that close. In fact, there's only 1 raised portion in the crankcase to really concentrate on (the shiny part on the right):



As hoped, there was no contact between the tin and the piston, which implies the clearance there is at least 2mm. I'll try to check if both old and new pistons are the same height, but I doubt the issue that destroyed my piston was with the piston banging against the crankcase...

Like I his on this post and over the years, Pinasco is a scam. They can't get their metallurgic together. Another thing that needs to stop is the "touring" reference.
There is no "touring", that is an invented word. Touring means nothing. You can "tour" on anything, the cylinder kit is not going to determine any touring.

You can just cruise at similar speeds and all the kits will do just fine but pinasco just happens to be the weakest...

My definition of a good tourer is the ability to maintain 60+ MPH over long distances, with a pillion and/or luggage, at reasonably low RPM, and without using tons of fuel or blowing up. This means lots of torque, higher gearing (24/63 on a P2 for example) and good heat dissipation. Nothing worse than a touring scooter that slows right down with the slightest incline or head wind. In theory you can achieve this with the stock P2 top end, but a well set up kit removes some of the variables and the 'black art' of O tuning. A Pinasco 225 achieves these objectives with ease. If you want something more or something different, I'll be the first to agree that there are better alternatives.

???
That's great on paper, but useless if you're stranded out in the countryside with a dead piston.

That can happen with any modified motor. Had a buddy just twist a crank on a Malossi 210, people hole pistons on good kits etc.

I had my Pinasco kit ported by HRS. Al's recommendation was 1,000 mile break in for the Pinasco. He also stated "Break it in like a dog and it will run like a dog, break it in right and it will run beautifully!"


I have been seeing that reference to hard break in for many years, It is the only article I have seen suggesting it, it has no references or hard data to back it up but people have been swearing by it for years. But if it's on the internet then it MUST be true.

Strangely I have never heard accolades regarding motoman's top 1,000 (+) music videos as being the definitive list. I mean...he put it on the same page so that must be true too!

Yeah you may break a race motor in that way but you're gonna open that one up at the end of the day anyway.

One may want to consider that hard break contrary to manufacture's recommendations may contribute to failures.

I don't know what THE correct method is, but the hard break in makes sense to me (despite the website and music videos).
Vader urged me to use it - albeit with cooling down between runs - and I haven't seized any motors since then. He said he did every motor like that and had never seized.

On another topic a friend bought a Pinasco direct '9 port' cylinder and there was no cross-hatching on the bore whatsover, just what he said looked like a chrome surface. He got a reassurances from a few sources to say it was ok, but he still remains a bit skeptical.