96db with R4 and Quiet Core II Insert?

I've got an '01 YZ426F with a White Brothers R4 muffler, and it's pretty loud....guessing over 100db's. WB makes a Quiet Core II insert that's advertised to quiet it down 5-6 decibels. Anyone try this out and pass the 96db test? If not, any other ideas to get the R4 and YZ426 to pass the 96db test, or should I just give up on the R4?

R4's was probably the loudest pipe made. I think you will have to upgrade pipes to meet a 96 db test.

I have the same issue... bought my 426 used with the R4 on it. Can you still get the quiet core insert for that model/year pipe?

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