Exhaust interchangeability

Here's the scoop for you guys bending and denting out there.

I have an 00 - 426.

I hate the POS headpipe because it is a bad design to have to fuss with it just to change oil - oil that requires changing often.

Both the 2000 and 2001 have different headpipe part numbers as we know.

But why the different muffler part number??? I asked. Maybe the true termination point of the headpipe to the muffer are not exactly the same????

I managed to get a complete 2001 system. I put on the 2001 headpipe, and it does mate with my 2000 muffler. So, to anyone out there (me) wanting also to retain a heat shield on the head pipe, you can mate up the 01 hedder with the 00 muffler.

So now, why then, the different muffler part number? Well, maybe someone who knows exhaust design and dyno affects can speculate on that. My guess is the the slight re-routing of the 01 hedder caused Yanmaha to alter the interior of the muffler slightly in order the maintain the same power curves.

Thinking this is possible, I put on the 01 muffler, so I plan not to discover how the bike runs with the 01 hedder and the 00 muffler.

I'll report back on how a 2000 runs with a 2001 exhaust.



I can only think of one thing. Didn't Yamaha increase the size of the rear brake disc from '00 to '01? If so, maybe the "dent" in the muffler is a different size :)



Pretty fly for a fat guy!

Thumper - you are right about the disk - I did not look that close at the indentation in the can.


I have been thinking the same way.

I have a '99wr with a '99 YZ muffler.

I was thinking about getting the newer header as well, but was not sure if it would fit exactly.

Then I looked at the Supertrapp page and noticed they list the same part number slip on muffler for the YZ for all years. This made me think that although the newer header has a different curve, it must finish in the same place as the earlier models.

Anyone got any opinions?

Hey guys, great to be back... :)

Here is the deal. 98-00 exhaust are all basically the same. O1 has a slightly wider head pipe, and it's out of the way of the oil filter. The 01 silencer has a noticably larger diameter pipe and core. I put an 01 complete system on my 99 WR and WOW. I love it, it revs out much quicker and made a notice jump in power throughout the power band.

Interesting note:

I really wanted a YZ exhaust but I was conserned about the fact that the YZ silencer had now spark arrestor. So... I went and rounded up a 99 and 01 silencer. I drilled out the rivets holding on the end cap to try and figure something out. I looked and looked for a spark arrestor screen that would fit and be semi legal. After months of looking I came up with a screen that is currently going the through governmental testing to become legal. I managed to get a screen and fanagled it in. WORKS GREAT! I realize that the silencer still says "only for close course use", but thats why they make sand paper! :D The company that I got the spark arrestor screen from is seriously concidering my idea of making a whole end cap assembly for the YZ's, and get this it should have a removable screen!

I'll keep you posted!


99 WR - WR timing, EKN #3, 01 YZ exhaust, Clarke YZ tank, YZ rear fender, IMS YZ seat base, Factory Effex YZ seat foam, Factory Effex graphics and seat cover, Decal works pre-printed numbers, Scotts stabilizer, Scotts upper triple clamp, Pro Taper CR Hi's, Trail Tech Panoram computer, Terry Cable hot start, DSP Carbon Fiber upper fork guards, Fastline Steel braided front brake line, Renthal grips, Cycra Pro-bend hand guards, GYTR triple clamp mounts for hand guards, Moose skid plate, GYTR front disk guard, GYTR plastic frame guards with 3M grip tape, Michelin S-12's, Renthal Groovelite sprokets, DID 520 X-ring chain, TM Designs chain slider, 5.6 Racetech rear shock spring

I have a '98 Yzf. Stock exhaust and have no problem changing the filter. Just loosen up the silencer clamp and the 2 manifold bolts, no need to rempve them. Then just rotate the pipe up and out of the way. Takes an extra 5 min at most.

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