Modern Vespa

Just like the title says, i'm looking for box exhaust options for my all stock P200 engine that i swapped into my wideframe VB1. In the past i'm a HUGE sito+ fan. The sito has always treated my right and i really like the torque and performance. I can usually eek out just past 70mph with the Sito as well. The only reason i'm not choosing to use a Sito once again is that i'm concerned about ground clearance with 8'' tires. So i guess i'm in the market for a different box exhaust that has better ground clearance. I'd like an exhaust that offers the same exact performance characteristics as a sito though. I think my options are pretty much narrowed down to a Polini box or a SIP road 2.0? I have already done a bunch of google searching and have come up with that some people are thrilled with the polini and didn't like the sip 2.0, but at the same time, i found that other people didn't like the polini and were huge fans of the sip 2.0.

The way my scooter is set up, it's meant for 55-60mph highway cruising. Of course there's lots of hills and headwinds that i have to contend with as well. If a Sito+ could be cut, chopped, modified, and rewelded without any performance loss, i would totally do that instead.


https://www.sip-scootershop.com/en/product/racing-exhaust-sip-road-20-0232-0259-for-vespa-200-rally-p200e-px200-e-lusso-98-my-cosa-200_24165500

https://www.sip-scootershop.com/en/product/racing-exhaust-polini-2002022-for-vespa-200-rally-p200e-px200-e-lusso-98-my-cosa-200_2002022?cr=e993ab67-6807-4109-bbed-f6374ebf9f9b&gQT=2

Are you leaving the gearing stock ? Might be short on 8' ?

I have a P200 motor with stock gearing on 8"s in my VBB. SIP Road 3 fits and has no clearance issues.

The gearing feels fine, just more like a 150 than a 200.

I did switch the gearing around for the 8" conversion. When i said a "stock 200" i meant that the cylinder, piston, head, crank, and carb are all still stock.

I tried DR177 with SIP R2 and Polini.
I tried VMC Super G with Polini
I tried stock 200 with SIP R2
I tried SeriePro 200 with Polini.

The last one is just done first km after rebuilding and I not gave it WOT, but even now it feels absolutely juicy and torquey.

On VMC I think that SIP will be better as it is able to give power on higher revs where Polini is almost off.

IMHO - Stock 200 just can't revs so high to feel that punch from SIP exhaust.

I had a Sito+ on 8's for a while. Definitely scrapes without much prompting. Changing to a SIP Road reduced scraping and gave more power.

I'm a big fan of the Polini box (which apparently is slightly wider than SR with similar ground clearance). But I think Roland may be right about the SR being able to rev a little higher, one day I'll try the one I have here and see how it compares.
Also like Roland not sure the exhaust timing on the stock 200 will let you make use of any extra revs? The stock 200's I've ridden seem to top out around 60mph, so you must be doing something right.

Seen these comparisons?

https://www.scootering.com/the-vespa-big-box-exhaust-test/

https://scooterlab.uk/vespa-big-box-exhaust-shootout/

ALL my stock 200's top out just over a GPS'ed 70mph. Some are 71, some 72, and one's a true 74! All i do is flow the carb to mixer box, then mixer box to the case. Drill the heart out in the air filter. Install a Sito+. Swap in a short 36T 4th gear. Last is add a flyscreen. No additional porting, no decking of the head. Of course those speeds change drastically in a headwind or a hill.

What i like about the Sito is that i can hold the throttle tube WOT and cruise at 65~70mph without fear of catastrophic failure from over revving. The sito has a perfect rev ceiling for my particular riding style.

The sip Road 2 works well on mine i believe the road 3 is good

As an update, i did a quick last minute switch up. I ended up ordering a SIP Road 3.0. I also looked at the Road 3.1. The only difference between the 3.0 and the 3.1 is that the 3.1 has two additional bungs welding into it, and it also has an O ring type sealing flange. Other than that they're EXACTLY the same performance. I was tempted to go after the 3.1 since it's only another $20, but upon looking closer at the pictures of it, the O ring flange doesn't look like a very good design. So if i have troubles with the 3.0 leaking, then i'll just weld in a different style of O ring flange to it.

The reason i chose the 3.0 for my stock 200, is that the 2.0 (according to graphs) has a lower RPM ceiling than a Sito+. I'm getting the impression that the Sito's performance lands right about between the Road 2.0 and 3.0? That being said, seems like you can't go wrong with a 30 year old sito exhaust design (that is, if you don't need the ground clearance).

Voodoo put a SR on an Allstate and had to modify it to tuck up higher to keep from dragging while cornering.

Scruffy AllState, crappy headlight finally fixed! (Post 2149588)

I'll definitely keep that open as an option! No doubt that since i have a P200 engine stuffed under this wideframe VB1, I have a feeling that some sort of additional modifications will need to happen. If there's room for me to tuck up the muffler closer to the frame, i'll definitely take that opportunity to do so.

in my andalucia thread have illustrated the Megadella for my DN.
It pulls from 20 km/h in 4th and revs to 90 km/h in 3rd. Fits perfe and is júst that bit slimmer than the Pollini.

I'd be very surprised if you don't find it better than the Sito. A little bit happened in the last 20 or so years.

And i possibly just might like the sip box better. I'll have to post up here again with my results after i get some run time with it.

I haven't received the exhaust yet, but on an offhand chance, does anyone happen to know what the jetting might be with the SIP road 3.0 on a stock P200 engine and carb? All my other stock P200 engines have Sito+ on them, and the jet stacks are a 160/BE3/125. 55/160 idle. That jetting works perfect for me for higher speed cruising on the highways. I'm wondering if the Road 3.0 will require a richer main.

125 on stock P200 sounds like a lot to me, stock it is 116 if I remember correctly. 120/122 should be well enough if the only mod is an exhaust.

Going higher than 125 won't have much effect unless you drill the fuel bowl.

It may be rich for inner city riding, but cruising for long distances on the highway it's been treating me pretty good for the past 25 years. I did forget to mention that i have also drilled out the heart in my air filter as well.

I guess the main thing i'm wondering is if the Road 3.0 will use the same main jet as a sito. Undoubtedly it will be different, but it would be convenient to have a known jetting value as a starting point.

Don't remember what main jet is on my touring P200, but when I swapped Road 2 to Road 3, I left the jetting alone and it's been a ok. If I had to guess, it's probably in the 125 range.