Tuesday, November 12, 2013

Putting a Vespa pipe on a Motobecane M11 the easy way... Will work on Variated Mobys and Peugeots with stock cylinder.

 So it's getting colder out and I decided to play with my Moby M11 tonight. The M11 doesnt have any direct bolt up performance parts so I've been thinking of what to do with making it a bit faster. So much like any other strapped for money mopedder, I racked my brain of parts and how they fit together, diameters, what parts I have to most of...etc. Well I have a Moby doppler pipe laying around but no mounting hardware or ball joint, so I'm not wanting to spend $40+ on that junk, plus the doppler pipe might be a little large for this stock shredder. So I have a few vespa pipes laying around and start thinking of how they fit up to bikes. Also thinking about how the Moby/Peugeot stock pipes/cylinders use a threaded header, so I need to keep the threads. Sarted measuring to find that the stock Pug pipe header was ~1mm smaller than the Vespa pipe header (22mm). Seem pretty obvious to what I should do, here are some pics. PS thx to the newest BLKBLK member Marvin Chan for the pug pipe!
 Top is the stock Peugeot pie, middle is stock Vespa pipe and bottom is the stock M11 pipe.
 Cut the stock Pug pipe around 2 1/2 inches from the header.
 Pretty easy bolt up. FYI the pug header seemed to be a bit warped so it tightened down better on one certain spot opposed to another. Gotta love that Italian seat clamp used as a pipe clamp.
 I chose a rando Polini Vespa pipe because it was small for mock up purposes.
Most of the threaded upgrades for Mobys I have seen have 90% of the time rattled loose. I'm amazed to see that aftermarket Motobecane/Peugeot pipe companies hadent adapted this technology of running a mount from the chamber to the headstud, especially on a variating engine. Oh well, check out my sweet MS paint pic. I did this slip fit header so I can try out different pipes as I please. Just gotta make a Sha intake for this bad boy and I'm off to the stock races. 


  1. Looks like it will work. This may work on other bikes that offer no performance parts. It's always good to think outside the box instead of always relying on retail-online spots to offer them.
    Thanks for sharing.


  2. I have found the main reason they rattle off is if the crush gasket is worn, or not crushed enough. I think it basically forms the seal and the friction that keeps it on there.

    Great writeup!

    1. thanks for the comment dan! i usually run 2 crush gaskets to prevent from the rattling. we had a hell of a time with one of the smaller chrome circuit pipes for mobys at the shop. we eventually ended up making a spring mount for it. i think it was mainley because other than at the threaded header, the only other point it was mounted was low and on the cases. i made sure to tighten the header tight and then made a bracket for the mount so it wasnt pulling the header in any direction. it still came loose! ahh mobys and their weird exhausts.... but hey, thats why mopeds are fun right?