Exhaust / Uitilaat Advice??

[NerdspeedTopic starterBerichten: 9]

Hey everyone-

Like Terrydean, I’m going to be racing in the Polini Cup in Atwater california. I’ve been frantically trying to decipher the descriptions of the exhausts in the tuning section. I need a pipe for the race bike, and soon. Unfortunately the Calibratas are not currently available in the US. What other pipes would you recommend?

My priorities are as such:
1.Durability
2.side-to-side ground clearance (for turning)
3.Mid-range to top end power
4.Cost

The bike has a progressive cylinder, 25mm carb, case-inducted 4 petal reed, polini variator with upgraded clutch spring and a lightened flywheel

The pipes that have caught my eye are the Homoet, polini, simonini
http://www.treatland.tv/vespa-piaggio-moped-simonini-performance-pipe-p/vespa-simonini-crazy-pipe.htm
https://www.1977mopeds.com/product/474/Piaggio-Polini-Mod-SP-Exhaust/
Let me know what you think!

bedankt!

[hansiebModeratorBerichten: 10922]

Perhaps you can look into this: http://www.vespa-ciao.nl/forums.php?m=posts&q=15157

We tested a few exhausts, here you can find how much KW -> KM is ( http://www.scooter-power.nl/boetenlabel4ve.jpg )

[Piet30DonateurBerichten: 1082]

the Simonini is a great exhaust but has very little ground clearance.

I think the Polini is not that good.

[MartijnvanheerdeDonateurBerichten: 2225]

Off: Nice oldtimer Piet! I like that style:bier

[EdjuhBijdragerBerichten: 6956]

I’d say polini top one since you ‘sport’ the 43mm kit.

What’s up with that 25mm btw.? Did you redesign your barrel so drastically that it needs a big carb like that or was it a convenience choice? I’d go for 16 – 19mm. Do you have a custom inlet manifold? Malossi engine or side-inlet?

Any pics of your racer?

[TimoO_DonateurBerichten: 3971]

I know exactly what you need. A Yasuni R or Yasuni C16 modified for your cylinder. I bet you tuned your Polini to a great transfer and exhaust timing. No original Vespa exhaust is build for this kind of cylinders.

[NerdspeedTopic starterBerichten: 9]

Thanks for all the useful information everyone.

Piet30- Does the simonini have clearance during turns? I’m not that concerned with riding over bumps since this will be mostly a track bike, but hitting the ground while turning would be a deal-breaker.

The reason for the big carbuetor (Tillotson HL360) is because ultimately I would like to build an even more aggressive engine, either out of a vespa or Honda Camino. TerryDean and I’s teammate has built a Camino engine with a LC Malossi MHR cylinder for a Aprilia Scooter rated around 18hp. The racing in California has heated up the ‘arms race’ in building fast mopeds for the hardcore guys out here. We will have bikes on par with the fast dutch guys probably within another year or two.

My blog: http://team-nerdspeed.blogspot.com details all the development, but here’s a pic or two:

Intake, under construction


Port Map

Exhaust – 186.30°
Mains – 128.6°
Boost – 131.4°

Paint Job, under construction

TimoO_ I will definitely look at the yasuni pipes, but because I don’t have much time left, I’d prefer an exhaust ready made for the Vespa.

[TimoO_DonateurBerichten: 3971]

Well, if you buy an Yasuni for minarelli horizontal it’s not difficult to make it fit on a Vespa. Looking at your timing, i allmost assure you a scooter exhaust will be the right choice Especially if you modified you’re cluch in a good way!

[Piet30DonateurBerichten: 1082]

Nerdspeed, I just checked the clearance to the side if you drive turns. My kick pedal arms would touch the ground first and then there is still enough clearance from exhaust side.

[ivovanzonBijdragerBerichten: 175]

Yasuni are really fast, but you can also order a calibratas in the netherlands and let them send it to your home..

[Gebruiker]

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