Yoshimura Machine Song GP-Magnum

[Mick In VT]

I Installed the Yoshimura exhaust yesterday. I’ve loved the low burbly sound they have on the YouTube videos, and the overall look and quality appealed. Several people reported not expecting any performance improvement, but I was still hopeful when I saw Yoshimura’s dyno chart. So once I got my hands on the new exhaust (less than 48 hours from ordering at WeBike to arrival in Vermont), the quality was everything I hoped for. Installation was easy (I had gotten a new OE exhaust gasket from Revzilla since it absolutely doesn’t come with the new exhaust). The OD on the stock exhaust pipe off the manifold is nearly 10mm narrower than the Yoshi, and the stock takes three 90 degree bends, while the Yoshi has a nice easy curve. As expected, the Yoshi sits tighter inboard on the motorcycle, almost fitting under the rear rack. Without the bulky silencer and heat guard, the odd shape of the right side cover shows the unused lower silencer mount. I’ll get used to the slightly awkward appearance. I started it up and got to hear the low burbly sound which was lovely, but as it revs up, it gets loud. One of the really nice features of the Trail is how quiet it is: not the case with the Yoshi exhaust. So how about that hoped for performance increase? My usual riding has a lot of moderately hilly terrain, and I often watch the speedo drop as I get near the top of a climb. My sense with a quick 30 mile ride was that it was much better at holding 40 on a hill, and even accelerating a bit, so while it won’t help top end, I think there is a noticeable improvement on hills. We will see how this may alter fuel economy- I get about 135 mpg these days. I’m including a couple of pics, one to show off the exhaust, and one to show the awkward look of the side cover.