Yoshimura RS-2 full system Review

[ThatGuyWithTheDRZSM]

In stainless steel with aluminum muffler can.




I bought this system despite hearing horrible things about Yoshimura's customer service, because despite their service staff having almost no knowledge of their own product, the engineers know the product well enough to design the system with dyno proven best horsepower results in the market. The reason for this is that the main restriction in the exhaust is the head pipe, not the muffler. Most other companies reproduce the head pipe in stainless steel, but the same diameter as the DRZ400E, which is larger than the S/SM but still not optimal. Yoshimura takes it further and makes a larger and properly tuned header, which is why few others compare.



There is one more exhaust that's better, also a Yosh, in the TRC titanium model line. It cost almost twice as much and was recently discontinued, "because it only fit the E model". (E is offroad, non street legaland not made after 2007). The difference is that the E exhaust has a different mid-pipe mount to the subframe - but what Yosh apparently hasn't figured out is that while the S/SM exhaust has a different mount on the exhaust itself - it has an extra hole in the subframe where the E mount is - so E exhausts will still fit S/SM bikes. So while they think they've discontinued an exhaust for a discontinued bike, they've actually discontinued one for a plethora of bikes still being made, with no equivalent replacement.

Fit and finish was perfect, no problems there. I had read about some people having problems with the left radiator contacting the pipe, requiring spacers being installed in the radiator mounts to move it up and off the pipe. Mine has a good 1/2" of clearance. I had also heard of it rubbing the rear shock spring, but I've got clearance there too.

The sound is spectacularly loud. Louder than most Harley's, but probably not quite as loud as some of the custom choppers you see around with a foot of header pipe and no muffler at all. It's slightly more attention grabbing though, because people are used to hearing loud V-twins - they're not used to hearing a loud 400cc thumper. It did come with a spark arrester insert that supposedly holds it to 96dB, but it also reduces the horsepower gain to almost nothing, so I took it out and don't even know what it sounds like. I'll have to put it back in if I'm on forest service roads.

The instructions, which reflects their customer service, were horrid. Their exploded diagrams were missing critical parts, and the spark arrester removal instructions were out of date by over a year. The design of the muffler changed in late 2007 to a non-removable endcap, and apparently their instructions were never updated. Fortunately I have a great resource in the DRZ400 section of thumpertalk.com, and found where several others had run into the same problems.