[Smallframe] Polini oder Parmakit oder M1

[keuk]

Hello,

I'm working on a new engine for a daily scooter.

The idea is to use the engine casing without weelding it.

Here are the parts I already have.

Short 4th DRT

Clutch DRT 8 springs

Koso 28

Polini reedvalve manifold with a fitted 28mm intake

2,86 with repair kit

Mazzu anticipated

ET3 ignition with 1,8kg Sip flywheel

PM40 exhaust or maybe Sip Road

I would like to use a cylinder without touching it too much, maybe the exhaust port but that's all.

So I think I could use:

- Polini 133 Iron

- Parmakit Aluminium touring (not the SP09 but the one with small transferts)

- M1

I saw on another M1 post that the timings of the M1 are lower than on a Polini... but i think i remember than the PM40 need 185° to work well at the exhaust port.... so what's the best choice for a punchy scooter ?

The thing is that I have already ordered the M1 on Sip, and I'm a bit disapointed now that I have seen the other post...

What do you think ?

Thanx

Antoine

Bearbeitet 7. Dezember 2011 von keuk

[heizer]

why not the new aluminium polini EVO?

send the m1 back

Bearbeitet 7. Dezember 2011 von heizer

[Brosi]

the new aluminium polini EVO?

Only raise the Exhaust port to 30° Blowdown and there you go.

Bearbeitet 7. Dezember 2011 von Brosi

[keuk]

why not the new aluminium polini EVO?

send the m1 back

Because the transfert ports are too big on the Polini EVO and i don't want to weld the engine casings.

Bearbeitet 7. Dezember 2011 von keuk

[Brosi]

Afaik there´s no need to weld.

[keuk]

Really ? Ooooh damned !! that's why they made this little edge inside the transfert port !! I thought the transferts were like a modified Quattrini but in fact their are more tight ?

Bearbeitet 7. Dezember 2011 von keuk

[keuk]

So it would fit like that ? (That's a Photoshop)

[wheelspin]

the evo kit would be my 1st choice for an engine like you want it.

if you don't open the transfers, you don't have to weld the casing

[wheelspin]

So it would fit like that ? (That's a Photoshop)

maybe the transfers a little smaller, but yes, it will look like this.

[Brosi]

Right. But you have to remove the "noideawhatitscalled". Just take a look at the official manual: http://www.gsf-shop....44534821536.pdf

Bearbeitet 7. Dezember 2011 von Brosi

[keuk]

Thanks for the advises guys ! So it will be a Polini evo to stay in the Polini family with my racer !

I will try to get rid of the M1 then...

[keuk]

One more question, I just took a look on the official manual, the Polini EVO has the same timings than the M1, 178/126, is there a big difference between both cylinders ? Of course the price, but for the performances ?

[Brosi]

Yes. The scavenge angles of the transfer ports does differ a lot. Where the M1 ist "designed" for high RPM the Polini has a reasonable mid and low rpm design.

High RPM meaning 10000 plus, mid an low everything below.

[keuk]

Alles klar, danke !

Bearbeitet 8. Dezember 2011 von keuk

[keuk]

Eine neue frage: Now that I have both cylinders.... M1 and Polini EVO, is the M1 a good choice to replace my old full machined Polini iron cylinder on my racer ? I have to choose between a upper size for my GS piston or something else...so maybe the M1 should be a possibility.