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Quietest silencer/spark arrestor for CRF450?

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I don't want to ignite a flame here. I have:

02 CRF450

FMF powerbomb header

FMF Ti-4 silencer/spark arrestor combo.

It passes the California 96 dbA sound test, just barely. I've repacked the silencer and sealed all gaps with hi-temp silicone sealant, but the bike is still way too LOUD for me at higher RPM and lots of throttle.

A ranger at Hollister Hills CA told me that in his opinion the White Bros E2 is the quietest one around, so I may buy one - but I figured I would ask this group's experience first :thumbsup:

Has anyone here recently tested different silencer/arrestor combos on the CRF450? If you have, pls. post here!

Thanks,

+sean

California, USA

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A lot of us run the stock exhaust and just add the PMB spark arrestor endcap plus the Silent Insert. I don't think anybody has failed the sound test with that setup, plus it's pretty cheap. Click on the PMB advertisement on the TT Advertiser's page for more info. :thumbsup:

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PMB... Fresh packing puts out 93/94dB on the sound tests in Oregon.

I 1st tried a FMF Q - I really did not like the mounting strap crap, and how far it stuck out the back of the bike (04). Plus I felt, it robbed too much power.

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hey zombie! I am running the same set up as you so i bought the fmf silent core insert! It quieted the bike down but took away to much snap so i pulled it back out and cut almost half of the length of it off and put it back in. I am pretty happy with it now, not to loud but still great performance. cost $25.00 give it a shot!

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Hey guys - thanks for the opinions.

vtec - Thanks! In fact I do have the quiet core... wonder if the previous owner cut it down already because it's loud. I'll look tonight.

I found this listing from the CA OHV division - it lists actual measurements taken at parks over the last year or so:

http://ohv.parks.ca.gov/default.asp?page_id=23038

I learned three things by reading it:

1) Sure enough, the CRF450s with stock silencers and Pro Moto Billet tips typically measured 92-96db - rather toward the low end of the scale.

2)I've been griping about how loud modern competition 4-stroke bikes are - but I see here that the CR500s I2-strokes I used to ride were just as loud.

3) My 02 KTM 125SX with FMF Q-series is indeed quiet. Those bikes came in at 89-91db.

+sean

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vtec, datasponge, and the others -

What kind of packing do you use, that makes it so quiet?

Do you pack it in tightly or sort of loosely?

+sean

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I have:

02 CRF450

FMF powerbomb header

FMF Ti-4 silencer/spark arrestor combo.

It passes the California 96 dbA sound test, just barely. I've repacked the silencer and sealed all gaps with hi-temp silicone sealant, but the bike is still way too LOUD for me at higher RPM and lots of throttle.

I thought I'd report back on the progress I made:

I made it quieter when I repacked it this time! Previously it measured at about 96db when I packed it not very tightly. This time I tried something different.

I noticed that around the perforated tube core there is a wrapping of two layers of stainless mesh screen that hold a layer of stainless steel wool inbetween them. This screen wrapping was pretty loose and was puffed out away from the core in many places.

I cinched it down tightly to the core by wrapping safety wire around it at 1 inch (2.5cm) intervals. Then I wrapped the fiberglass packing tightly around it and wrapped that with masking tape. I sealed all the joints with a TINY bit of hi-temp silicone sealant.

Result: the bike is A LOT quieter - it's nice to ride now!

And it measured at 94.3 db at Metcalf yesterday.

So,

was: loose screen-wrapping, lightly-packed fiberglass, 96.5db

now: v. tight screen-wrapping, tightly-packed fiberglass, 94.3 db!

Yippee!! it is pleasant to ride now. :cry:

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I have the same set-up 2002 and went from a FMF system like yours and was too loud for a local track (which I respect), so I searched a way to quiet it down and ended up with a White Brothers E2 slip on, and I have to say the thing is so easy to change into a race system, and when i get to the track that sound tests, I slip in the sparkarrestor/silencer end cap and test in the 92-94 range. No noticeable change in power, the only thing different is the delivery just slows down a little. When I had the FMF Ti-4 I put in the "quiet core insert" and the bike nearly choked to death. . .

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