Will Bolt on Mallosi 210 sieze if porting work not done?

Hi All,

What are your opinions on bolting a Malossi 210 on without porting, will the engine still run happily or will it seize in time. I have a polini 180 on my 125 at the moment and the porting has not been done and I have covered 11000 miles without any issues so what do you think?



hello Pyperb,

sorry, I don’t remember your set up, if you could write it down it will be more clear what to do to improve it .

Let put it straight: I love them all, Pinasco, Polini, Malossi, it just depend for which use I need them. It is like saying that a great trial bike it is not good for highway use.

Polini 177 is one of the most dependable kit around. Yes I know somebody here had some problem, but what can I say…
I have been reported of people doing a lot of km with this kit and I include myself among them.

With a Polini 207 don’t expect a lot more power. You just will have a better curve and torque and you will be able to use a longer gearing ratio without feeling frustated.

I personally have never had problem with the big Polini but since many peaople reported problems and broken pistons I don’t feel in the position of saying you won’t have a problem. Sure is I would not use a Polini 207 for highway touring. But I generally don’t use my vespa for highway.
But for city use no other kit come close to the Polini as if you want to go fast you can’t do better than using a Malossi 210.

In your case since you already have a good base, I would invest more to improve it at its best instead of starting all over again with a PX200 engine. You will need a good cranck a good carb, porting…
the choose of the correct head, that is not that granted…
so if in your set up there is room for improvement it is where I would put my money.
If you don’t use aoutolube you could go for a keihin PWK28 that I love, you could get a high end exhaust, porting your cases if not already done.
As I said at the opening I don’t remember your set up so…

You will have no problems it will just be slow. You must get the head reprofiled or else it will pink its nuts off. Taffys ,Readspeed, Harry out of Grand prix or any of the German shops can supply this. Malossi 210s have port timings which means that they dont make much power untill they are reving fairly high which is why you’ll do 70 in third and 60 in 4th. The polini is a much better bolt on kit in terms of power but the pistons are shit( not so bad on the 180s or small frames) Two solutions are to bore it to take a malossi piston or one of the german shops (not sure which)is bringing out their own pistons. Down side to the malossi piston option is it makes the barrel a one shoter ie there is only one size of malossi piston. In my opinion (often wrong) malossi are only any good on balls out reed motors or down geared motors.
In answer to your question it wont seize but you may fall asleep riding it.


With my Polini 180 I get 65-68 max, if I had a 200 engine with Polini208 and a good pipe what top speed could I expect or would it not be worth it since the Polini 208 is meant to seize a high speeds.




This is my setup…

PX125 Disc 2003 model
Polini 177 bolted on no porting work done
SI 26/26 Spaco Carb
Simonini exhaust… 125 main jet…timing not sure…plug Bosch W3AC

Top speed on flat 65-67mph no wind
Downhill (BIG HILL) 70 mph

I’m not greedy, I prefer to go 70mph all day rather than improve BHP acceleration but would love top speed just over 70mph.

What would I need to add in order to acheive.

Thanks and Regards,


I think Curare knows a lot about polinis but my experience of them in the 80s was that they were great around town but motorways were a bit of a lottery as to whether the pistons would hold up. If you took the time to port your 180 properly you would unleash so much more power you would think its a different bike. Its not the difficult to match the tranfers and you can increase the inlet by buying an off the shelf racing crank. Add a 24mm carb from a p2 or t5 and you have 18bhp. This is enough to make your scoot happily achieve 70 all of the time. Not only this but it will accelarate well also. My advice to you is to buy an old px engine and have a go. If you balls it up-no matter you just learn and try again. This forum seems full of great people who are free with help and info so what have you got to lose? Once you’ve had a go you’ll wonder why you didn’t try it before.

There is no point in doing a bit here and a bit there. If your gona have the engine apart just go for it. In the 80s some of my mates had taffspeed polini 180 engines with 28mm dellorto and mickeck pipes. These would *** all over most vespas including bigger cc and this was in the days when we used to try and get every paddy smith patch there was so they were very reliable. I get the impression that you dont really want to port the casings though. There is only one vespa engine where you can bolt a kit on and there is little else needed for a fast engine and thats a T5. They are expensive but a mallosi kitted T5 meets every criteria you have listed. If your going to spend money anyway buya T5 motor.

…then of course you will able to get what you are looking for.
First of all you should match your cases to the polini barrel, and doing the inlet port work opening, explained in Polini instruction. Then you should get a Mazzucchelli race crank.
At this point would be a good thing to get a 28Keihin or keihin pattern (Koso or Oko).
After all this you will be able to get what you are looking for and having some room for improvement in the future if you get a JL RH2000 or right hand.
Gearing ratio either 21/65 or 22/65.
After this if you are not satisfied you have two choices: or consider some professional help …or surrend yourself to the passion of neverending tuning… or both…


Can I do these in stages…get the porting work done…see if scoot will reach 70+ if not get the crank…see if reaches 70+ etc.

I hear the noise/sound on the Keihin is great…is this true and would the engine sound more beefy than the 26/26?


I would do both at once as it would be a lot cheaper to do the crank and porting work at the same time while the engine is out and in bits unless you are doing the work yourself and don`t want it to go too much over 70?

I’d agree with diablo to a degree there.The Polini is a far more powerful option as a bolt on but,as he said,the piston’s suck.The Malossi will be fine if jetted right but I will disagree on the reed valve opinion.A rotary valve induction will fly if ported and set up right,it just won’t be as fast and responsive as a reed valve or a Polini with the same work.

If you go with a Polini instead get the ready honed version as the tolerance’s are far too tight on an unmodified model.


I am close to diablo and JuanK answer.

You won’t have any problems, but you would not like it either. Bolt on better a Polini or Pinasco depending on which use.
For the city Polini .
You have to make the Malossi rev high to awake it. It means porting, reed, bigger carb…

Tanks to you all guys for your support during my accident.