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Plated 09' XCF 450 with EXC exhaust questions

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Asking for some advice...

I have an 09' XC-F 450 that's plated here in Georgia and I need to quiet it down and be USFS approved. I also have to meet the 96 db to ride at a lease I'm a part of in North Florida. It's currently factory exhaust reading over 100 db at mid throttle 20" out and 45 deg w/ my decibel meter before and after repacking. Thinking of a couple cheap options for used OEM exhaust to quiet her down from Ebay (or here if anyone wants to part with anything):

XCF-W/EXC OEM muffler to get just below 96 db

or

EXC Street legal exhaust that claims to be ~80 db. (is this exhaust USFS approved? I couldn't find much on it)

Both are around $100

I would love to be super quiet at the 80 db mark, but my main concern is will the street legal exhaust put too much restriction on the engine? It runs hot already and don't want to make it any worse. It's jetted w/ a JD kit, one tooth down in the front for trails (back to the factory for the track) everything else is factory. I am not worried about losing any power, there's plenty already there I'm not using on the trails. I imagine I would swap back to the XCF muffler when riding the track.

End goal for the bike is to throw an upgraded stator kit to add a fan and power my headlight. I understand that buying an EXC would pretty much solve all my problems, but I like to ride the track every once in a while and can't justifying buying a new bike.

Thanks!!!

Edited by Dave Fialkovic

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The EXC street legal exhaust is very similar to the XCF-W/XC-W OEM muffler except that it has some additional "parts" welded to the inside of the perf core of the muffler if I am not mistaken.  It will be USFS approved, just like a stock XCW silencer.

The more you choke it up, the hotter it will run.  I have modified a stock Honda 450X silencer to fit my 505 (it was the right price: free) and it makes the bike insanely quiet (around 82db) but it also runs incredibly hot if I do not change the jetting around.  I use that every now and then, but otherwise I have an FMF Q4 which always sound tests under 96 for me at races and is spark legal.

If the two exhausts you are looking at are the same price, I would start with the super quiet EXC exhaust and work from there.  You can always knock one of the internal baffles out to let it make a little more noise and not build up as much heat (well still being under 96db) easier than it would be to make a stock XCW exhaust quieter (if you needed to do that).

If all you need to hit is 96 and be spark legal, then just get the used XCW exhaust.

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I dropped my main by two sizes (185 to 180) and then effectively gave up, as that was the limit of the brass that I had on hand at the time.  I did need to drop the pilot another size, as I had the fuel screw at a half turn out.

I should point out that when I was using the super quiet setup at the time, I was riding at around 1000ft, which is a lot lower than the normal 4000-6000ft range that I regularly ride in and I am jetted for.  I would think (and again, this is pretty much a guess) that for the same riding altitude, at least a three to four size drop in the main and at least one on the pilot will be necessary as a starting point.  I can easily see going down a lot farther on the main when all is said and done with how choked up the bike will get.  Frankly, if I were to put the 450X silencer back on I would probably start out again with a 175 main, 40 pilot, and then see where it would take me.  I normally run a 185 main, 42 pilot, and adjust my fuel screw based on elevation.

I will note that I didn't see any huge decrease in the bottom end power (it was mellower), but the top end was neutered pretty significantly on my 505.  I have done a few different silencers over the years, and have come to really like the Q4.  It makes the power that I want, with an acceptable noise.  I leave it on even when I am racing MX.  I could put the stocker back on, or a Yoshimura I still have, but the Q4 works so well I don't bother.

I will give the super quiet silencer another go later this year, but right now it is on the back burner as I have a few races coming up shortly and that is what my 505 is set up for.  When it gets to mid June and I am done racing for 2 months I will probably re-visit the super quiet setup for trail riding on the KTM.  I will obviously do a little more in depth work on getting it to run right at that point in time.

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Q4 definitely sounds like what I need, but way out of budget lol. 

Looks like I'm gonna roll the dice with a 780.05.082.000 with the Krizman spark arrestor. Listed for the 09-11 250 XCF-W and 450 XC-W for $95 shipped.

Hopefully it gets me below 96...

Thanks for all your help eastreich!

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That should work great for what you need, and it should easily put you at 96 or below.

Have fun with it!

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Update on the XCF-W exhaust...

Still above 96db. Not by much , right around 97-97.5db mid throttle. Definitely quieter than the 101 I was seeing before. The new muffler is missing the screen and nut on the tailpiece that goes on the EXC's. Would adding those two pieces make that big of a difference on the noise? It's another $20 or so, don't want to waste any more than I already have... also looks like it would reduce the flow a bit more...

I have a Pro Moto Billet Spark Arrestor End Cap I was running on my factory muffler I tried to see what difference it would make. Worse... It is about a 1/2 to 1 db louder and noticeably deeper. The port is quite a bit wider, so I wasn't expecting it to be much better. They make a couple inserts for it, the "Pro Moto Billet Silent Insert" (3-5db reduction) and "Pro Moto Billet Ultra Silent Insert" (4-6db reduction) both for $44.60 ea. I don't know how much I believe it. Any experience or suggestions? Kinda leaning towards this to maintain flow and hopefully get me down a tad more...

 

Silent insert.jpeg

Ultra Silent insert.jpeg

Favtory insert.jpeg

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Ordered an PMB Ultra Silent insert off Amazon for $44.60 shipped. After swapping out end caps, it definitely breathed better with the PMB. While I think the KTM screen cap would have got it below 96, I don't want to get that head any hotter than I have to. I'll put up all my numbers after it comes in, hopefully before this weekend...

On a different topic, got my trail tech fan installed, seems to do pretty well on keeping the temp down. Set it on 175F. Don't know where it levels off yet, but sitting idling it gets over 180F with the fan running, but it just barely creeps after it kicks on.

Rode around before and after installing the new muffler, didn't seem to make much different in engine temp that I could tell.

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Got the PMB insert the other day. Fail... So much for the 3-5 db claim. Got it down from the 97.6 to right about 96.7 db. I don't know how strict the guys at the lease are with the 96 rule, the way I see it, if it's not 97, it's still 96... The only thing is they only test once a month and have to wait until then to even check.

Eastreich you were definitely right about trying to quiet down the XC-W muffler... Probably should have listened and started with the EXC super quiet and knocked stuff out as needed. I just wanted to hit 96 and be done... The bike also performed pretty similar to how you described, bottom end was all there, top end a little more mellow. Engine rev seems to linger a lot more after you let off the throttle too, not as snappy as it was before. Haven't quite had a need to use all the power at the little track I ride at, but my every once in a while last second roll on to clear a couple doubles nearly cost me yesterday :lol:

Any suggestions? If they don't give me the pass, should I try and sell everything off and get the Q4? Try the EXC route? Throw another $20-30 for the KTM factory screen and cap insert? I am at a loss and full of frustration. Thanks!!!

 

Edited by Dave Fialkovic
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