Honda’s new patent to revive under the seat exhausts

Honda has still not forgotten the awful underseat exhaust trend on sportsbikes and that is reiterated once again if you manage to see the newly released patent drawings that has been submitted by the Japanese giant.

But that’s not all. If you look at the patent drawings closely, you will see the presence of two exhaust banks; one ending with a muffler on the right side while the other with a convoluted one that ends abruptly within the rear fearing.


Underseat exhausts first started showing up on bikes in the 1970s, with the aim of allowing engineers to extend the exhaust pipe without having to curl it here and there. Engineers back then felt this was a good idea for the same reason Honda’s engineers do now; as the patent filings claim: “It is desirable that the tail pipe be formed as long as possible to increase flow velocity of exhaust air in the final stage.”

The trend caught up once again in the late 90’s and early 2000’s when the underseat exhausts hit the market again. Even bikes with no sporty intentions started featuring underseat exhaust. No study has proved that the underseat exhaust manages to provide any performance benefit. The only intended reason could be the cosmetic one which many people thought looked cool.


However, it certainly did not feel cool as the underseat piping had becomes notorious for frying the asses out of the bike riders, especially the passengers. The trend anyways started to die about a decade ago and it seems Honda is very interested to bring the idea back from the dead.

Honda’s new design hides all the emission business in the rear cowl of the bike. Designed to work with a V4, the hot exhaust from the engine’s rear runs through a twisted maze of metal into a bedpan shaped muffler which then exits from a single pipe. Meanwhile other gases coming from the front of the V4 take the more traditional route through the side exhaust.

How and where Honda is going to put this system under use and what benefit is derived out of that is not known and might lead to interesting speculations.

You can view the patent drawings here:

Honda Patent

[Source: Rideapart]