KLX400R Big Gun exhaust quiet core sizes

Hi All,

First time poster and lifetime rider.

I checked ThumperTalk threads before posting this issue.

I have a KLX400R 03 with a big gun exhaust, Per the rules in the NETRA series I need to be down around 96db. I contacted Big gun today to get a new quiet core insert in which they asked length, my reply 15inches, since that is the length of the muffler and I'm guessing the length of the sleeve and the diameter of the opening. Before I start thrashing the muffler apart does anyone have those measurements available to them?

Thanks, krg770

I had the old style big gun race pipe. It ran pretty good...but was probably the loudest pipe I ever heard.

I had to quiet it down for a forest ride...and so I bought a quiet core insert for it. You have to repack the muffler to put it in...and it was noticably quiet...but it also totally erased all the power gain I got from the pipe.

If your going to do this...your going to need a repack kit too.

I ended up taking it right back out...cut it in half to reduce the number of flow obstructions...then slit it length ways...so I could insert the short section inside my race core. Then after the ride I removed it to regain full performance.

They did provide testing on that ride. My bike measured 98 dcb with the cut down quiet core inside my race core.

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