speed engine,

[pink floydTopic starterBerichten: 45]

Hello everyone I need some help,i’m running a 46.5mm Malossi cylinder on my Bravo, but the original crankcases I had bored to 50mm are not in good shape. I would like to buy a Polini speed engine, but would the ports match the Malossi cylinder, or do I need to buy a new 46mm polini cylinder as well?

[LeonM93BijdragerBerichten: 154]

The ports are mainly always on the same places, but if want to tune ur cilinder by also making the boosterports match with ur engine, u will have to use a dremel anyways.
But the prefabricated ports in a speed engine will match the cilinder’s ports.

[ArvidWDonateurBerichten: 6258]

No, the porths won’t match. 46.5malossi uses triangular main transfer porth channels and polini uses more a rectangular shape with radius in the corners.

You’ll have to mill the crankcase and cilinder in such a way that they match.

Buying a polini 80 won’t solve the problem, even these transferporth channels do not match the speedengine perfectly.

AW50-4t | 13.13 | Gianelli Citypower | 3.2Nm@6000rpm | 3.0pk@6700rpm
Home made engine dyno

[EdjuhBijdragerBerichten: 6956]

They don’t match but it’ll run nice though, there’s the auxiliary ports in the piston to help get the juice from A to B.

And as said before you can always grind your way to perfection.

[pink floydTopic starterBerichten: 45]

Thanks guys, I had been looking at pictures of the speed engine and I could see the port openings in the Polini crankcase were alot different to the ones in the bottom of my Malossi64.5.
I don’t mind doing some milling, I had to do loads of work to my standard crankcase to make the Malossi ports match up good,
but this crankcase is in a poor state and I would like to start again with a new speed engine.
So you think it will be posible to match the Malossi to the Polini, I didn’t want to get one sent over to the U.K. and it didn’t work, shipping cost’s are high!!

[Gebruiker]

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