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View Full Version : 400ex/ 450r exhaust on 350x



Doppler
11-25-2010, 01:45 AM
Well I ended up getting a 400ex header and a stock 09 trx450r muffler off ebay. Actually got the header from the 450r also that I cut up and used to make the custom midpipe. It's a pretty straight foward swap. You have to cut a little off the end of the 400ex headpipe to make it fit as it is much longer than the stock one and will not fit with the frame in the way. After that it bolts right up to the head. Then you bolt on the muffler and then make a midpipe to connect the two. Just a little mocking up and fab work. I used the stock connector/ gasket for the front of the midpipe and the stock 450r connector/ gasket for the rear of the midpipe. I did this so I can use gaskets instead of silicone and clamps also. I had to cut off the end of the stock headpipe and weld it on the new one, and also cut off the front flanged part of the stock muffler and weld it on the front of the midpipe. Then for the rear of the midpipe I cut off the end of the 450r headpipe and welded it on so that it would slip right into the muffler.
This setup gives a nice power increase over stock and sounds better also, but it is very quiet. That can be a good thing but I wanted options and a little louder so I just bought a LEXX MXe muffler off ebay this past week. RockyMountainATV is the normal supplier for them, it's a high quality muffler. Only downside to this over the stock 450r muffler is it's length, it is about even with the grab bar. The stock 450r is much shorter. Oh well it looks good and sounds great!

mrtwidster1
11-25-2010, 08:22 AM
Great work!
I have had the 400ex header and a FMF MegaMax muffler on my X for 2 years. I really like the looks of the lexx muffler and will have to look into one of those. Thanks for the write up and the pics.

bigbadktm
11-26-2010, 08:51 PM
i like the look of that muffler as well, i think if I had an x, that would be the way i would lean

Dirtcrasher
11-26-2010, 09:18 PM
Whats the hop with the 400EX headpipe? I'm told it's the same inside diameter as the stock 350X, so just it being newer is why people use them?

Yours does look great, I just don't know why everyone wants one. Either my source is wrong or both ID's of the headers are the same...........

jason85atc250r
11-26-2010, 09:23 PM
I second what Dirtcrasher said.