P500 Noise reduction on P520

[stobiadas]

Hi everyone.
It's been a while since I checked out this site. I've had my 520 since ,21 and I love it more everyday. Have done some mods, most of which came from this site. In pursuit of trying to make it more quiet I accidentally stumbled upon a stupid easy mod that I wanted to share.
So for the sake of discussion I have installed a rubber mat under the seats, also experimented with snorkel/intake and additional foam in various places to reduce noise. Tried putting an extra muffler behind the stock exhaust and took it off after finding it awkward and bulky. And quite honestly I was disappointed in the sound with the muffler. The "little mod" I did to exhaust actually made it quieter than the muffler. Here it is....just a little extension on the muffler tip. Yes I experimented with different lengths.

 

[Admin]

 

[futzin]

Thanks for the feedback.

I own three P5s. They all sport a (@trigger) Quick Shield to attenuate noise and heat.

The easiest decision in the history of decisions . . .

 

[pappyo]

Opened up exhaust to 2inch </> removed 2 Baffels </> drilled 8 --1/2 Holes in the 3rd Baffel.
Lowered only 2/4 Dcebel -- & changes to DEEP Mellow Tone

ADDED --18inch Tailpipe ( Vary NOTICEABLE Difference )
"" LOWERED "" </> NOISE LEVEL --10/12 Decibel -- ( depending on RPM ) -- & changes to Mellow Tone

MEASURED WITH -- Smart Sensor Digital Sound Level Meter ST9604
Without re-taking readings ( if memory is working ) 90/ 92 --) down to -- 80/ 78

Have Done On:
FYI: ( All -- gained Better Mid Range Power -- when Done with Snorkle)
P500
P520
P700

All -- have under seat rubber barrier & commercial grade rubber back carpet for insulation. ( BEFORE Exhaust changes ) never measured before under seat changes )

Moral of the Story TAILPIPE "DOES" Help Noise Reduction. & ( Does NOT-- Loose Power -- like 2 mufflers )
A little Trickey with working dumpbox. ( room restriction's )

 

[stobiadas]

Opened up exhaust to 2inch </> removed 2 Baffels </> drilled 8 --1/2 Holes in the 3rd Baffel.
Lowered only 2/4 Dcebel -- & changes to DEEP Mellow Tone

ADDED --18inch Tailpipe ( Vary NOTICEABLE Difference )
"" LOWERED "" </> NOISE LEVEL --10/12 Decibel -- ( depending on RPM ) -- & changes to Mellow Tone

MEASURED WITH -- Smart Sensor Digital Sound Level Meter ST9604
Without re-taking readings ( if memory is working ) 90/ 92 --) down to -- 80/ 78

Have Done On:
FYI: ( All -- gained Better Mid Range Power -- when Done with Snorkle)
P500
P520
P700

All -- have under seat rubber barrier & commercial grade rubber back carpet for insulation. ( BEFORE Exhaust changes ) never measured before under seat changes )

Moral of the Story TAILPIPE "DOES" Help Noise Reduction. & ( Does NOT-- Loose Power -- like 2 mufflers )
A little Trickey with working dumpbox. ( room restriction's )

How did you remove the baffle? When you say you opened up exhaust, did you cut the muffler open?

 

[pappyo]

All done from back of muffler With Out Removing.
Purchase
1-- yamaha aluminum muffle new tip -- online
( purchased at Ford Tractor Dealer. ) 1 -- vary large Flat Washerbig enough to fit new tip.

Remove Muffler Hear Shield ( will have to trim alittle when ready to put back on )
Using Saber Saw -- With GOOD metal cutting Blade
Cut 3/4 Out let pipe off muffler
Drill a hole big enough for Saw blade
Curt hole just a little SMALLER than OD of New Washer( going to weld washer here later )

For Warned Next Step is -- Royal pain in the Tush -- Wear Gloves
"Sharp" Long Chisel </> carefully </> little at a time </> trim rest of 3/4 pipe & Remove 2 baffles.

You will be at ☆ Star Burst Baffel. ☆
Need extra long drill bits. & long center punch
Start small & Drill 1/2 hole between every other point of ☆ at outer diameter

Open up the center of large Flat Washer to match ID of New Tip. ( Donot weld on at this
Align the tip on Washer mark. & Drill holes -- put bolts through back side of washer
( Align tip&bolts weld head of bolt to back of washer )

Check how your going to locate & 《 attach tailpipe if going to use one.》at Same time locate Washer & tip on the muffler
Last step depicts the Angle the New Tip Needs to be at.
Time to spot weld.
Check Fit-- Recheck -- check some more before finish welding.

FYI: Made a gasket for tip to washer
used a SS sink strainer for Spark Arestor
High Temp PAINT

Have a Excellent Memory -- But it DOES Leak

 

[DaveinWV]

stobiadas, what diameter pipe did you use and how long is it?​

 

[trigger]

@stobiadas

 

[stobiadas]

The tailpipe is made of steel tubing that came off a cheap generator cage/handle. It fit perfectly into original muffler tip. I played around with different lengths to fine tune the sound. It seems longer is better for sound, but it will be prone to damage. I compromised between length and sound. I've also been playing with the length of the intake pipe . Seems the diameter and length of snorkel is having an impact on power and sound levels. The "thump" of the single lung sends a pressure wave up the intake tube and greatly affects the overall flow. You can actually feel the power drop off at certain rpm's as the sound changed simultaneously. It's a try and repeat process and seems to be a Ballance between intake and exhaust. I'm still playing with it, so will report when I'm happy with the setup.
Thanks @trigger 😉

 

[DaveinWV]

Thank you. Dave