Muffler improvement power increase
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Joined: 07 Jun 2009
Posts: 57
Location: jarrow
Wed Jun 09, 2010 11:04 am quote
is this a 4t or 2t exhaust your cutting up
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Wed Jun 09, 2010 12:33 pm quote
The photos you sent are the correct configuration of cuts and pipe
Et4 Vespa 190
Joined: 04 Sep 2016
Posts: 2
Location: London
Sat Sep 10, 2016 11:44 am quote
Hey guys I have a 2001 et4 leader with a malossi 190 , malossi variator, upgraded clutch spring , brand new shape scorpion racing exhaust , first time getting in to 4stroke as I grew up riding 2stroke and always thought 4strokes sounded dreadful and performed worse 😬 But . ( this is a big but too ) I have absoloutly fallen in love with my little Vespa !!! I removed the first baffler/muffler from the exhaust and this baby sound like a bad ass , the backfire is off the chain it is crazy crazy !! Best sounding 4stroke I have heard . Although my close friend has same bike same set up , he's got a pollini gear up kit and a pm tuning exhaust, I encouraged him to remove his silencer and wow I might be in love with his bike 😂😂 awesome bikes
Cheers guys and gals happy riding
'79 Vespa P200E Daytona
Joined: 19 Jan 2013
Posts: 86
Location: USA
Sat Jul 01, 2017 7:23 am quote
Hey, Defendo. Are you still monitoring this thread? I have a few questions for you. I'm very intrigued by your mod and the reasoning behind it.

1. You used 1.5" tubing and said up to 1.625" would work...why? The exhaust valve on the ET4 is only 21mm (.826"). Also, the long u-shaped header pipe inside the stock muffler is approximately 24mm (.94"). Consequently, replacing the tube that you replaced (stock size was aprox .75") with a 1" tube should be near perfect, as it matches the header diameter. I've got my stock muffler apart right now, and am about ready to weld in a 1" tube, which is .25" larger than the stocker. Thoughts?

2. Are you still running your modded muffler? What is your experience with it in the long-term?

Many thanks.
Vespa 150 ET4
Joined: 16 Apr 2021
Posts: 2
Location: San Francisco
Fri Apr 16, 2021 8:22 pm quote
Vespa Sprint muffler on Vespa ET4
Can it be done by closing the ie intake hole
Joined: 21 Feb 2021
Posts: 49
Location: Deep Doo Doo
Tue Apr 27, 2021 9:54 am quote
Re: Answering questions
Defendo007 wrote:
The true test is overall performance. The speedometer being at 70 is my indicator for now.
Yeah, but...I thought LX150s could do 70 mph out of the box anyway.

I put a Turbo Kit GMax pipe on my LX50 2V. At first I loved the ridiculous loop in the header. I thought it comical, and so to embellish I wrapped the pipe with header wrap to give it a little more visual irony and character.

With the baffle in, it's loud. With the baffle out, it's loud. Also it drones really bad in or out. The scooter stumbles from a stop. Torque after a stop is good, but as you go faster the pull loses steam quickly. It probably only goes 48mph or so I have no idea, speedo is broken. Need to fix it. I no longer have to jump off and push it up the hills so I guess that's something.

I also have a less restrictive air filter, the Malossi double sponge. Also have the 78cc BB kit, and the performance camshaft which lets the head breathe better.

I like the pipe but I don't really think it does much for the performance, just makes it louder. That loudness is not the same loudness as from a Ducati. A loud scooter is a sonic menace. A loud Ducati is music. I'm losing the pipe and putting the stocker back on as soon as I stop being lazy about it. Also going back to the stock air filter element.

As gasoline engines are really only air pumps you have to think about fluid dynamics and the flow of gasses, thermodynamics etc etc to get the most power out of one and it's not a straightforward thought process i.e. you won't gain by just throwing a pipe on there, by making the exit less restrictive. Entrance needs to be loosened up as well, and also the flow within the cylinder head. I've got all the mods you can get and mine does not satisfy me with the way it runs after all the work & expense. I tried to balance the pipe with the airbox and camshaft and came up short anyway. Yes yes, I tried a full compliment of Keihin branded upjets and downjets as well. Just runs like crap compared to stock. It has more power yes, but the rideability has gone to sh*t.

So I am going to have to say this to the OP and I don't mean to be rude but- dyno sheet comparing stock to modified or you are simply talking out of your butt. As a lifelong motorcyclist I say this; butt dynos are not valid in this argument. Numbers talk, BS walks.
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