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stroker101

09 YZ450F STK exhuast

27 posts in this topic

had some time to today to modify the stk muffler that was on my 450F.

i drilled out the rivets and removed the "perferated cones" from within the muffler. repacked, reassembled and resealed the muffler.

the muffler is definetly louder LOL. seems to rev a bit more freely. haven't ridden it yet to see if any low end power was obtained.

anyone have any info / experience they could share with a mod like this?

thx :excuseme:

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get a slip on instead they sell for what an endcap is worth on ebay and definately feel the difference more hp up top

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get a slip on instead they sell for what an endcap is worth on ebay and definately feel the difference more hp up top

My PMB endcap and SS Megabomb header combined are about the same cost as a slip-on. I tried a full PC system and much prefer the performance of my set-up.

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well, i just got back from the track and all i can say is this modified stock muffler is AWESOME!!! i wish i would have done this before i spent the $$$ on the LEXX Slip-on and the money used for the LEXX could have been spent on the PMB End-cap.

definetly more grunt down low. good for comimg out of tight corners, hitting the inside lines, hitting jumps right out of turns and it excellerates much faster

if ya have a stock muffler laying around and have about an hour or so to kill, try this mod. you won't be disappointed

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I also have an 09. What exactly did you remove (picture maybe) and did it make it too loud and did it hurt your top end power?

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the mod didnt make the exhaust note that loud, it is louder than stock however. it is probably as loud as any aftermarket muffler. i didn't feel any lose in the top end, still rips!

not sure how to post pics on here. maybe someone has a link to what the inside looks like.

this is how i did it...

the perferated cone thats "inside" of the perferated tube, the spot welds have to be drilled out in order for the cone to be removed.

the perferated cone attached to the end cap simply needs to be cut off. i left about 3/4" sticking out past the inside of the cap.

i used a cut-off wheel attached to a phneumatic cut-off tool

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Did mine tonight, didn't fire it up to let the silicone dry. Wished someone would have told me I didn't have to remove the part attached to the midpipe. I think I could have just removed the endcap part.

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if your going to remove the cone from inside of the main perferated tubing, then all the rivets at the bottom section that is attached to the mid-pipe need to be drilled out also. i dont see how you could get to it if the muffler body wasn't out of the way

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On mine the cone is attached to the end cap and nothing else. If I were to drill out the rivets for the end cap and just remove it, the inner cone would come out with the end cap and the outer cone would stay intact with the exhaust.

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On mine the cone is attached to the end cap and nothing else. If I were to drill out the rivets for the end cap and just remove it, the inner cone would come out with the end cap and the outer cone would stay intact with the exhaust.

He's referring to the secondary cone which is farther down in the core.

08muffler.jpg

08muffler2-1.jpg

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so looking at the photos to do the job of removing both cones,you have to drill out the rivets on both ends,and remove both ends.correct?

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so looking at the photos to do the job of removing both cones,you have to drill out the rivets on both ends,and remove both ends.correct?

si senior! and it will "BARK" afterwards lol

thx dvn for the pics

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My bad. I didn't even see the smaller cone inside the tube. Excellent pics by the way. I think I will try it with just the larger cone removed first.

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hey blaker213,how did the mod work out for you?did you repack with stock packing?whats with the plactic bag over thepacking?same question for you stroker 101.

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hey blaker213,how did the mod work out for you?did you repack with stock packing?whats with the plactic bag over thepacking?same question for you stroker 101.

plastic bag? are you reffering to how new packing is packaged? when i disassembled the stock exhaust from my 09 yz450f, the stock muffler packing didnt have a plastic outter wrap.

the DRD packing that i have is designed like a "pillow" with an fiberous outter shell.

and yes, i re-used the stock packing as it was in "like new" condition

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