Re: Moto 7 released from its shackles

Aaron Summers Effler /
This single post is part of a larger thread. Start from the top or view this post in context.

there are four different stock exhausts from motobecane. the two piece is not very restrictive, but it was only put on AV88's and AV89's, out of the ones imported into the US. it is designed differently, but performs similarly to the least restrictive "cashew" style exhaust made for the imported 40's, 50L's and 50v's in the early 70's. they had a "40" stamped on them (between two motobecane symbols), and only one crimped rib perpendicular to their length (like the one in that ebay auction you linked). these are the pipes that people like stephen keller likely have, they will run up to nearly 40mph on a ported stock 50V. i've also seen them going 45+ on a parma kitted 50V.

in the latter part of the 70's motobecane started replacing the cashew exhausts with the newer, quieter model. they are stamped "40 - 85" between motobecane symbols, and have two crimped ribs instead of one (running perpendicular to the length of the pipe). if you swap one of these onto your 50v that previously had a two-piece or fast cashew on it, you'll loose 5-9mph instantly. unfortunately the design of this pipe was very similar to the design of the 7's pipe. both were meant to run quieter, and meet environmental restrictions in some countries.

so, you've got a couple options. 1: modify a fast cashew or two-piece to work with the angle of the seven's motor. 2: modify your 7's stock exhaust to open it up a bit, and see if that helps (see my post, above). 3: buy an after-market motobecane exhaust, which would likely have to be modified to work with the 7's mounting geometry (like the homoet in this post). 4: buy one of these and modify it (if it's needed). this pipe came on the most recent MBK's and the AV-10 model 51's sold in europe and imported into canada. it's not restricted the way the slow cashew is, and it may just bolt right up to the seven (but you might need to make a bracket, or re-shape the header). 5: put a VLX pipe on it, but you'll want to derestrict it first, and modify the mounting hardware a little. it performs similarly to the 7's stock pipe. i have one i'd part with, if you're interested, and it's already setup for a model 7.

good luck, and post pics when you're done!

This single post is part of a larger thread. Start from the top or view this post in context.

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account