Piaggio SI- new project

[rubymaxTopic starterBerichten: 73]

Hello,

I ‘ve just bought a reasembled piaggio SI.It is not in very good condition but i hope I can make it better.It has an electronic ignition- CDI, sito plus exhaust, and complete kit DR EVO 43 (cylinder, piston and original DR 43 head for SI. The inlet/intake for carburator is now 11,5 mm (original) and the carb is 12/12.The ports on the crankase is original and don’t fit the DR 43 ports and boosts. It also has the original vario 90 mm.

I want to do the port matching on the original crankases that will fit the DR EVO cilinder, make the fi 13 inlet for carb ad maybe do some work on the original crankshaft. What about the carburator 12/12? Do you guys think that I should change it with 13/13 or leave it 12/12 and buy just polini or malossi airfilter an upjetted. I also dont have an original gasket for DR EVO (block/cylinder) because it was fully damaged during reasembling.

I ‘m open for any of your suggestions

Thank’s for answers

[freddy kBijdragerBerichten: 456]

The 13/13 and 12/12 are both an good option.
Just with the 13mm you have a little bit more torque.
Gasket are cheap and can be made out of gasket paper. (you can get it at any autostore or garage).
If you drill the inlet you best mount a 13mm carb.
And the cilinder will work fine on untuned crankcases.
But modified its a beast. polini torque and malossi speed. well almost :p.
original crank is good enough but if you want to modifie it you can.
Depends on what you want to do.

[rubymaxTopic starterBerichten: 73]

I thought that when I will reasembled and renewed the whole engine it would be fine that I also enlarge the carb intake to fi 13mm, because maybe in the future I will buy a 13/13. Do you think that this is not good if I use a 12/12 carb and fi 13mm intake? What about the main jet , I think 62 or more?

I ‘ve heard that for proper case matching ports and boosts for DR EVO cylinder you should do some work with liquid metal- epoxy. What about that?

What thickness of gasket paper you recommend me for do it yourself gasket (0,5 mm or more)?

I have also intend to buy malossi vario, whic weight do you think will be appropiate for my setup?

Greetings from Slovenia:)

[freddy kBijdragerBerichten: 456]

A 12mm aint that bad.
I would recommend a jet 60 – 64 depends if you transfer the ports of your cilinder in your crank.
Then i would say a 62 – 66+.
The 6g weights deliverd with the malossi multivar and yellow pressure spring work fine in combo.
You dont need epoxy or liquid metal.
just be carefull (:
These are mine (for a tuned malossi 43mm)

If you split them you can see how far you can go.

[rubymaxTopic starterBerichten: 73]

Hello,

I have another important question. I know that on this forum were many tags about proper measurments for editing the original piaggio crankshaft. But I’ m little confused about all of them. Can anyone maybe suggest me the right/best measurments to cut off/anticipated the crankshaft – like on polini or malossi instruction 15 mm and 10 mm or 15 mm 5 mm for editing the original cranshaft for DR EVO 43 cylinder, 12/12 with power filter , sito plus and malossi multivar 90 mm?

Thanks for answers

[freddy kBijdragerBerichten: 456]

Hey,

Original crank will work fine.
You can cut off 5mm for early opening and 5 – 7mm for closing. (sort of my method on belgian engine’s)
But with an sito plus an original will work more then fine.
Cutting the crank is good for high rev engine’s.
You can tune the cilinder instead.
1mm higher exhaust port 4mm wider (2mm each side).
Torque and revs will increase a bit.
But if you cut the crank its possible it will be out of balance wich can destroy the engine from the inside out.
Also if you would tune your crank i would recommend an polini speed engine carter set.
It has a bigger inlet + possibility to mount 16mm carbs. and with the varioreducer (round spacer for between de front vario disks).
Its possible to block it from further variation so it woudln’t drive to fast etc.

Friendly regards.

[Gebruiker]

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