Stock 07 450 db level

[FreshDonutsCAN]

Does anyone know the exact sound level for a completely stock 07 yz450. I ask as i am probably gonna get a PMB endo for my bike as i need to make it legal for harescrambles (needs spark arrestor). Should i purchase the silent insert or is it not neccesary at all. 96db is limit. Thanks

[NorCal]

Does anyone know the exact sound level for a completely stock 07 yz450. I ask as i am probably gonna get a PMB endo for my bike as i need to make it legal for harescrambles (needs spark arrestor). Should i purchase the silent insert or is it not neccesary at all. 96db is limit. Thanks

Sound testing is different everywhere you go. I have an 06 YZ450F with a

complete 07 exhaust and the rangers out in California tested it at 99 dB (with

PMB endcap w/ Sparky). I bought a silent insert in case of a sound test at a

race. Well, last race they were doing sound tests so I threw the insert in and

it passed "just barely" according to the rangers. The limit was 96 dB, but they

were letting guys slide within 1 dB. My packing is pretty old, and I'm almost

positive I didn't pack it right, so that could contribute to why it was so loud.

IMO, the silent insert really cuts the power down and makes it feel more like a

250f. The money invested in the end cap, sparky, and silent insert makes me

wish I would have just gotten a full aftermarket exhaust that is designed to

test at 96 dB.

[FreshDonutsCAN]

IMO, the silent insert really cuts the power down and makes it feel more like a

250f. The money invested in the end cap, sparky, and silent insert makes me

wish I would have just gotten a full aftermarket exhaust that is designed to

test at 96 dB.

thats why im worried about spending almost $200 on something that may cost performance

[FreshDonutsCAN]

what about the Ultra Silent insert is it really any different from the silent insert on the PMB endos. Does it really hurt the power with the insert any opinions would be nice to hear!! Thanks ?

[Diesel_Junkie]

I have a full 08 yz exhaust on an 08 WR.... the Pipe is much more powerful than the WR stuff in any configuration(uncorked WR).

I got the PMB tip, spark arrestor, and ultimately both the quiet tips.

The Ultra quiet insert tested at 97.5 db at Hollister hills.

The quiet insert tested at 98 db with the same test equipment(but different days)

Hollister keeps the microphone at about 45 degrees from the pipe and at 18" away.

They claimed it was too loud both times, but let me pass for 96 db both times too.

i might have bad packing, I bought it used, and didnt inspect it before putting it on.

The funny thing is that Hollister tested it as too loud, but at another enduro race the testers listened and decided it was too quiet to test and just gave me the sticker. i think there is a lot of variability in testing schemes, and they are all flawed some how... i would sware this thing is not really that loud of a setup.

[KAS]

I have a stock '07 muffler on my '08. It is usually right around 98, 99dB.

[thumpyz]

i had a pmb endo on my 04 yz, and that thing shears rivets everytime i ride, with or without the spark arrester. maybe my packing is bad. me and a buddy put that same exhaust with the endo on his 426, and he shears rivets too. so my opinion is that your money is better spent somewhere else.