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fnxnlab

how do you get an '03 YZF450 to pass the California noise test?

13 posts in this topic

I've got the Promotobillet silencer insert, but I tested at 96.8 dB, only 0.8 over the limit. I did a little redneck trick to make it pass, but the trick was, well, temporary. This season the officials may test bikes after the race, so I really need a permanent solution.

Anyone have, or know of, a YZF450 passing the 96dB noise test? There are several options for aftermarket silencers, but I don't want to drop $350+ unless I'm at least a little confident that it will get me to an acceptable noise level.

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I've got the Promotobillet silencer insert, but I tested at 96.8 dB, only 0.8 over the limit. I did a little redneck trick to make it pass, but the trick was, well, temporary. This season the officials may test bikes after the race, so I really need a permanent solution.

Anyone have, or know of, a YZF450 passing the 96dB noise test? There are several options for aftermarket silencers, but I don't want to drop $350+ unless I'm at least a little confident that it will get me to an acceptable noise level.

You passed the test.In a field test you are given a leeway of 1.5db so anything under 97.5 is passing. :thumbsup:

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Also make sure you have fresh packing. Get something like the silent sport packing, repack the silencer and ride for a day then have it checked (to simulate checking after a race). If you have the cash, then as said above the FMF -Q has a stellar reputation as a quiet exhaust.

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the blue one, I got robbed! Damn. I wish I had known about the tolerance on the noise test. The officials failed me and weren't going to let me race.

Thanks for the advice Sirthumpalot. I'll try the repacking trick and see how that works.

I was looking on motosportoutlet last night for an FMF Q, but they didn't have one. They sell a "Q" insert for a TI4 cannister though. Anyone have any experience with the Q insert in the TI4?

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I have the "Q" insert in my 17" Ti4 on my YZ250F and it's runnning right around 98 with the "Q" and just over 100 without it. My brother has an 04 WR450 and without the "Q" he's running arround 110. I don't see what the "Q" does on the Ti4 personally, it's built to be loud. It didn't help too much in my opinion. I put some "Q" pillow packing in my pipe last night and now on idle it's runnning 80Db and about 96 to 96Db at ~1/3 throttle but it still runs 120Db when the throttle is wacked full on for a sec. The only problem is that it's smoking pretty good because the Ti4 runs hotter than the "Q" pipe so the packing won't last as long. I'm looking for another pipe now also because I'm tired of trying to find ways to quiet my bike to pass sound tests every year for only two races (I race in Texas and NM and except for two races we don't have sound tests). I'm looking into the PMB replacement end for the Stock YZ exhaust with their quiet insert guaranteed 96Db or less.

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renegade, thanks for the lowdown. FWIW, I'm running the PMB insert, silencer, and spark arrestor and I didn't pass the 96dB test :thumbsup: Lame.

Yamadog68, I'll check out the white bros. solution. My buddy called white bros, fmf , and pro circuit today and said that nobody wanted to gurantee that their product would get you down to 96dB. Kinda sux.

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Paul Krause told me that when they ran the ISDE, they had to line the airbox and cover the top of the box because there more noise from the engine then from the pipe.

I did a DB test and confirmed it.

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Wow FactoryFairbanks, that's interesting. What did they line the airbox cover and top of the box with? What were your noise readings on the engine and out of the silencer?

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Paul Krause told me that when they ran the ISDE, they had to line the airbox and cover the top of the box because there more noise from the engine then from the pipe.

I did a DB test and confirmed it.

Good point! Many of the off-road quiet type bikes come with intake silencers (most riders promptly remove them).

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