04 yz450f pass sound test?

7 replies to this topic
  • fastbyfrank

Posted March 13, 2006 - 12:47 PM


hi everyone i have a question and i have done a search already.
i am thinking of entering a few poker runs and enduros this summer and i was curious if anyone knew if my 04 yz450f with factory exhaust and a dr.d spark arrestor will pass the sound tests? i have had people thank me for having a quiet 450?(a guy at tahuya thanked me for having a quiet 450, he said that alot of people were "uncorking" their exhaust and it was going to close the riding area) i do know that it is way quieter than my 426 that had a white brothers e-series exhaust but i just dont know if it will pass the sound tests or not. i have never sound tested anything ever and i dont even know how they do it.
thanks in advance for all the quick replys! :thumbsup:


Posted March 13, 2006 - 12:51 PM


I can tell you how the AMA does sound tests, but I dont kow if you're doing AMA races.

The AMA sounds tests bikes at half the rpm of peak horsepower. A YZ450F's redline is at about 13500 RPM. Peak horsepower is at around 10500 RPM. That means the sound test is done at 5500 RPM. Whatever decibel rating your bike puts out at that engine speed will determine if your bike passes or not. If people are thanking you for having a quiet bike, it will probably pass. Because there are some bikes I consider loud that pass the AMA's sound test.

  • fastbyfrank

Posted March 13, 2006 - 01:01 PM


thanks for the quick reply, i dont think any of the poker runs or enduros are ama sanctioned. i was on the drd website and i saw a quiet core insert that will work with my drd spark arrestor endcap. it is 39.99 i figure it coudnt hurt to buy it and try it, i would hate to get to the event and have my bike not pass the sound test.
does anyone have experience with the quiet core insert? does it change the power delivery? do i have to rejet? i would love to have a nice quiet bike with no horsepower loss or minimal horsepower loss.
thanks, have a nice day. :thumbsup:

  • jwcrf05

Posted March 13, 2006 - 06:05 PM


i have a dr. d and without the insert you are way too loud. you will need that quiet insert to get it to pass the 96db test. mine puts out something like 101 to 103 on an 05 450f

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  • fastbyfrank

Posted March 13, 2006 - 06:51 PM


hi, you have dr.d endcap on factory exhaust? or dr.d system?
thanks :thumbsup:

  • jwcrf05

Posted March 13, 2006 - 07:01 PM


its the full stainless system including the header. sorry didn't realize you were only running the endcap, thats probbaly totally different.

  • 133_Bradley

Posted March 14, 2006 - 04:56 AM


I have a '04 YZ420F and it has the stock exhaust. At 4500 rpms it was 103 db but I have repacked it since then and I'm not sure what it is now.

  • 133_Bradley

Posted March 14, 2006 - 05:00 AM


YZ450F I meant

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