2008 Yz450f quiet exhaust question

13 replies to this topic
  • motomanwr250

Posted October 27, 2010 - 11:38 AM


I want to start racing hair scrambles with my 2008 yz450f i just got. The entire bike is stock except for a procircuit t4 slip on which is way too loud to pass the 96 db test.

Any suggestions on which exhaust i can get that will consistantly put out 96db or less for the test with the least loss in power.

  • YamaLink

Posted October 27, 2010 - 02:19 PM


The least loss of power. That is a tough one.
Wonder if a Pro Moto Billet SA with quiet insert would work.

  • Beatcoaster

Posted October 27, 2010 - 02:23 PM


I have an FMF Q4 on my 2010. I haven't done any db testing, but it was way quieter than stock and I didn't notice a change in power...

  • RM125rc

Posted October 28, 2010 - 05:41 AM


remember that NETRA just changed their sound requirments to 94db

  • motomanwr250

Posted October 28, 2010 - 06:11 AM


oh 94 db will be tough but a friend of mine mentioned leo vince anyone used this system? Pros? Cons?

  • twomancrew

Posted October 28, 2010 - 07:06 AM


Would repacking it help?

  • ForsheeMS

Posted October 28, 2010 - 08:03 AM


The Leo Vince is about the quietest system I've seen. The slip on comes with a spark arrestor insert and the packing lasts longer than anything else I've used.

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  • motomanwr250

Posted October 28, 2010 - 08:54 AM


sweet deal. ill have to go check out the leo vince system then

  • stroker101

Posted October 30, 2010 - 04:27 AM


LEXX MXe Slip-on...
•Fully tunable exhaust system allows the user to change from a race exhaust (46mm Race Tip) to a forest friendly silencer (Quiet Core Insert) with just three bolts.
•Engineered to improve torque and acceleration with an increase of up to 4 horsepower on some machines.
•Lightweight design saves up to 3.5 lbs over the stock exhaust.
•Included 46mm Race Tip for closed course competition.
•Includes Forest Service approved Quiet Core Spark Arrestor Insert that brings sound levels down below 96db.
•Optional tuning exhaust tips and optional screen type Spark Arrestor are available to allow user to further tune power and sound characteristics.
•Constructed of lightweight 6061 T6 aluminum and durable 304 stainless steel.
•Limited lifetime warranty.

  • FinchFan194

Posted October 30, 2010 - 01:28 PM


I have a LeoVince slip-on on my 08 and it consistently puts out 95-96db.

  • mike_dean

Posted October 30, 2010 - 03:02 PM


FMF Q4 with a power bomb header measured 94 db at the last dual sport ride on my '00 YZ426, it was 101 db with a Pro Circuit T4, it's so quiet all I hear now is engine noises. Still has great power.

  • JDLowrance

Posted October 30, 2010 - 06:20 PM


FMF powercore or powercore ti with stainless PB header and the 94dB insert is nice and quiet. All my buddies and I are running them on our 05 through 09 WRs with no issues.

Very nice power increase by the way. And, they are 20% off starting Nov. 1.

  • motomanwr250

Posted November 05, 2010 - 07:56 AM


thanks for the advice i think im going to try leovince becuase it is the cheapest.

  • usp4u

Posted November 05, 2010 - 08:30 AM


thanks for the advice i think im going to try leovince becuase it is the cheapest.

I'm running the Leo slip-on also. Never had it tested though. Pretty quiet with the spark arrestor and quiet core. Excellent build quality too.

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