modern BOX exhausts, de-throttle your engines :D
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Enthusiast
px244gs, cosa221LX, sprint177, gilera runner 180, triumph tiger 955
Joined: 09 Sep 2013
Posts: 64
Location: vienna/austria (the other one, w/o kangaroos)
Mon Sep 07, 2020 1:28 am quote
cheers guys!

to be considered:
1) the sip road 2 #sr2, as ingenious as it was 10y ago is nowadays a throttle. a lot has changed, huge ingenious boxes wer
2) a FAT body/manifold is not needed for good power
see polinibox and slx8, they perform better as optical fat boxes like
sbox3 (horrible sound!) and siproad XL and XL viper and also compactL

checkout my #FMPboxtest 2020:
https://www.facebook.com/pg/freakmoped/photos/?tab=album&album_id=2389236811184447


polinibox and megadella slx8 are state of the art box exhausts in 2020
sr1, sr2, srXL design is from around 2010 = 10y old = outdated
(xl 2014-2015)

polinibox is made by an italian proper exhaust company, thats the reason why its THE box to beat nowadays. unbeatable: the price.

polinibox vs srXL:
https://www.facebook.com/freakmoped/photos/a.2389236811184447/3173078322800288/?type=3&theater

sr3 vs srXL:
https://www.facebook.com/freakmoped/photos/a.2389236811184447/2815513885223402/?type=3&theater

forget that an optic FAT manifold & body is needed, its not
see how the slx8 swallows the XL

https://www.facebook.com/freakmoped/photos/a.2389236811184447/3173091009465686/?type=3&theater

slx8, sr1, srXL, sr3:
https://scontent-vie1-1.xx.fbcdn.net/v/t1.0-9/118421840_3138619589579495_7259519308729696921_o.jpg?_nc_cat=100&_nc_sid=cdbe9c&_nc_ohc=yLHfs4jmWWYAX9yG8nu&_nc_ht=scontent-vie1-1.xx&oh=7a719ce11e6335fb78b0e00e9209a157&oe=5F7A96DD

polinibox vs sr3
https://www.facebook.com/freakmoped/photos/a.2389236811184447/2578308798943913

dont like the sr3 so much, only bit better in high rev (that you dont reach anymore in 3rd gear) but loss in low rev
its too similiar to the polinibox, which they tried to copy & improve
but its too close. noise a bit on the annoying side & its also hanging too low sadly...
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1653
Location: UK (South East)
Mon Sep 07, 2020 3:00 am quote
Thanks FMP. Which box exhaust do you recommend for a T5 with Malossi 172 and SI carb? The SIP XL is produced with a T5 connector, but the Polini box would need an adapter to fit a PX exhaust to the T5
Molto Verboso
2007 Stella 225
Joined: 02 Nov 2019
Posts: 1552
Location: Rochester, Minnesota
Mon Sep 07, 2020 5:21 am quote
This still makes me want to buy a Polini for low rpm touring use. The only other one seems to be a BGM big box touring.
Ossessionato
79 P200E, 62 Allstate, 2008 Stella
Joined: 11 Jan 2006
Posts: 2072
Location: Florence, OR
Mon Sep 07, 2020 9:05 am quote
Thanks for putting this together FMP! It's much appreciated!
Enthusiast
'13 LML '70 Sprint Veloce
Joined: 01 Aug 2019
Posts: 77
Location: London
Mon Sep 07, 2020 10:52 am quote
My Sip road 2 got really noisy after about 4 years so I switched to a polini. I didnít really notice any different power characteristics and itís not much quieter. Maybe I got a noisy one..
Hooked
Enough for the wife to tell me to slow down
Joined: 28 Jan 2008
Posts: 332
Location: Johannesburg
Mon Apr 12, 2021 4:25 am quote
Sip XL Viper
Hey guys and girls its bee some time since I visited this group to ask any questions as i usually just follow quite from the sideline.

also sorry to revive a 7 month old thread

I have a P2 with an old malossi 210 top end, standard gears, standard cut and flowed crank, Malossi Power exhaust and a PHBH30 carb, the bike is amazing but as per the age old issue where the 4th it runs out of torque especially on hills and headwinds,

I was suggested to try an exhaust that has a better torque which was most likly one of the new box style units.

I read an article from https://scooterlab.uk/vespa-big-box-exhaust-shootout-feature-2/

and seems the BGM BBS would be the best BUT ground clearance factored in the Viper from SIP seems to be the better option of them for this reason

can someone confirm that what I have read in the article and let me know would the Viper be a good option for my set up

I know I can change to a T5 4th gear but that wont suit me when I am on tour on the freeways and back open roads.... I do 70% cafe racing and 30% Touring
Hooked
PX 200
Joined: 25 May 2016
Posts: 260

Mon Apr 12, 2021 6:11 am quote
themod1 wrote:
Hey guys and girls its bee some time since I visited this group to ask any questions as i usually just follow quite from the sideline.

also sorry to revive a 7 month old thread

I have a P2 with an old malossi 210 top end, standard gears, standard cut and flowed crank, Malossi Power exhaust and a PHBH30 carb, the bike is amazing but as per the age old issue where the 4th it runs out of torque especially on hills and headwinds,

I was suggested to try an exhaust that has a better torque which was most likly one of the new box style units.

I read an article from https://scooterlab.uk/vespa-big-box-exhaust-shootout-feature-2/

and seems the BGM BBS would be the best BUT ground clearance factored in the Viper from SIP seems to be the better option of them for this reason

can someone confirm that what I have read in the article and let me know would the Viper be a good option for my set up

I know I can change to a T5 4th gear but that wont suit me when I am on tour on the freeways and back open roads.... I do 70% cafe racing and 30% Touring
The PHBH setup properly? 300 needle valve? Float height set? If not, youíll likely run into problems, especially in 4th because your float bowl will start running dry...
Hooked
Enough for the wife to tell me to slow down
Joined: 28 Jan 2008
Posts: 332
Location: Johannesburg
Mon Apr 12, 2021 6:19 am quote
Thank you 108 I have spent a long time on the PHBH and have been running it for at least the past year with about 10000km on the kit and carb at this point...

it took me close to 3 weeks to get the right size needle and seat, needle position and basic tune in but yes the 300 needle valve was one of the things I changed
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1653
Location: UK (South East)
Mon Apr 12, 2021 7:26 am quote
How about the SIP Road 3? The BBS, SIP XL and the Viper all fall into the 'like an expansion chamber' category, so will deliver their best shots at higher RPM. The Road 3 will give you a better spread for touring, as would the Polini box. You could also drop the clutch gear to 22 tooth as an easier alternative to the 36 tooth 4th. Easy to go back if you don't achieve your goal.

Are you up for porting the cylinder? Maybe your existing exhaust is fine, but you need to deliver more power in the right place ie. to hold 4th.
Ossessionato
Joined: 26 Oct 2015
Posts: 2949

Mon Apr 12, 2021 7:45 am quote
I'd spend the few hours it takes to install that 36T short 4th gear. If you feel as though it raises your RPMs too much while touring (30% of the time), then also install a 24T clutch. Most all of us here spend LOTS of money on our fancy cylinder kits, why not also invest just a little into our transmissions as well? Hills and headwinds can be difficult for high RPM cylinder kits. That's where gearing comes into play.
Hooked
PX 200
Joined: 25 May 2016
Posts: 260

Mon Apr 12, 2021 7:52 am quote
themod1 wrote:
Thank you 108 I have spent a long time on the PHBH and have been running it for at least the past year with about 10000km on the kit and carb at this point...

it took me close to 3 weeks to get the right size needle and seat, needle position and basic tune in but yes the 300 needle valve was one of the things I changed
3 weeks? it took me 8-9weeks...! No dyno and was jetting too lean at the bottom and too rich at the top... balanced out, but looking back, the performance was terrible...

I didnít add a 300 needle valve until mid of the life of the PHBH, so just bringing that up...
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