NOISE TESTING RESULTS

NOISE TESTING RESULTS
The standard mufflers measured here are all as stock issue to the Australian Market.
Those available in other countries may differ with correspondingly different noise emission levels.

Starting 2002, all readings will be published at both MA and FIM rpm.

The MA limit is 102dBA, the FIM limit is effectively 99.9dBA

These measurements are made in accordance with Australian noise regulations which differ to those applied in the USA.
Even within the USA there is a wide variation in the test rpm that an individual model is tested at and attempting to make
any comparisons between these results and US results is pointless.

Make	Model	Exhaust		MA dBA	FIM dBA	Comments
		Readings taken at Connondale Thumper Nats July 2002
Yamaha	YZ250F	Brown Brothers	Fail	104	102
		ProCircuit T4	Fail	104	103
		FMF Titanium T4 2002 model	Pass	102	101
		as above with flat end cap	Pass	100	97
		Yoshimura	Pass	102	103	Interesting that this is louder at 5000rpm than it was at 6160rpm. We double checked to be sure, to be sure.
		Standard	Pass	97	96
		DSP Titanium Oval 2002	Fail	103	102
		DSP Stainless Round section	Fail	106
		Staintune - no end insert	Fail	104
		Staintune - smallest insert	Pass	102
		Giannelli	Pass	100	100
Yamaha	YZ426	CRD	Pass	99	99
		OVER	Fail	104	101
		DSP Titanium Oval 2002	Fail	103	102
Suzuki	DRZ470	Yoshimura	Fail	102	101
KTM	400	Acerbis	Pass	98	97
	540	Akarapovic Titanium	Pass	100	99
	520	Akarapovic Titanium	Pass	100	100
Honda	CRF450	Leo Vince L X3	Pass	102	100
		DSP Titanium	Fail	104	103
		Bills Pipes	Fail	106
		Doma	Pass	101	101
		FMF Titanium 4 - without insert	Fail	105
		FMF Titanium 4 - with insert	Pass	102
	XR250	FMF Powercore 4	Pass	99	99	This was on an older model XR250
	XR250	FMF Powercore 4	Pass	102		with spark arrestor mesh on standard header on a 2002 model bike.
	XR400	FMF Powercore 4	Pass	101		with Spark Arrestor and FMF PowerBomb Header pipes
		2001 & Earlier Readings.
Yamaha	YZ400F	Standard	Pass	101
		Std 426 muffler	Pass	101
		FMF Powercore 4	Fail	104		Freshly packed even.
		Noleen High Velocity Output (HVO)	FAIL	108		High Velocity and High Noise
	YZ426F 2001	Standard	Pass	101
		Arrow	Pass	101
		Yoshimura Slip on	Pass	102
		Yoshi RS3 Stainless	Pass	102		Freshly packed
		Yoshi RS3 Stainless	Fail	105		Old packing
		White Bros 'e' Series with tapered header, end cap & torque valve	Pass	102
		As above w/o torque valve	Pass	102
		White Bros R4 with tapered Header	Fail	106
		White Bros R4-modified Version	Fail	108
		White Bros 'e' series with 12 silencer discs	Fail	104
		R&D YZ	Pass	101
		As above with 6 discs	Pass	102
		DSP Titanium	Fail	105
		ProCircuit T4 with screen	Fail	105
		FMF Powercore 4	Fail	105
		FMF Powercore Q Series	Pass	100
	YZ250F	Standard	Pass	99
		Arrow Aluminium	Pass	101
		DEP with standard header	Pass	98
	YZ125	Standard	Pass	98
		Noleen	Pass	101
		FMF Shorty	Pass	102		Make sure you keep the packing up to this one.
		FMF Powercore 2	Pass	99
	YZ250	Standard	Pass	100
		FMF SST	Pass	102
		Noleen	Pass	102
		ProCircuit 304	Pass	100
Suzuki	DRZ400	Standard	Fail	103
		Standard	Pass	101		Remove end cap and insert muffler packing outside the spark arrestor mesh.
		Standard	Fail	104		Spark arrestor mesh removed
		Full Yoshimura system	Fail	104
		Full Yoshi RS-3 Stainless	Pass	102
		Yoshi RS3 Titanium	Fail	103
		Yoshimura muffler on a standard suzuki header.	Pass	102

KTM	400SX	ProCircuit T4	Fail	105
		Standard	Pass	96
		Standard - shortened	Pass	99
		Duma Racing	Pass	100
	520SX	Arrow Titanium	Pass	100
		Standard	Pass	95
	520EXC	ProCircuit T4, small end cap	Fail	104
	540	Arrow Special	Pass	100
	250SX	ProCircuit 304 silencer on Std Chamber	Pass	100

HONDA	CR125	ProCircuit 304 silencer on Std Chamber	Fail	104
	CR250	ProCircuit 304 silencer on Std Chamber	Pass	99
	CRF450	Standard	Pass	101
	CRF450	FMF	Fail	106
	CR500	Standard	Pass	101		Freshly packed and well tuned.
	CR500	FMF	Pass	102
	XR400	Barrett	Pass	100
	XR650	DSP Stainless Steel Fact	Pass	101
	XR650	Custom Galale Bros	Fail	104
	XR650	HRC	Fail	104
	XR650	ProCircuit T4	Pass	102
HUSABERG	550	Standard	Pass	100
	600	Standard	Pass	100

HUSQVARNA	570	Barrett	Pass	96		There are a number of slightly different
		Barrett	Pass	98.5		versions of the Barrett mufflers. All
		Barrett	Pass	99		passes well.
		Standard	Pass	94
	610TC	Barrett	Fail	103		Older model. twin horiz tail pipes.

The above tests results were obtained using the testing method described in the Manual of Motorcycle Sport 2001 edition.
In essence an exhaust cannot exceed 102dBA at 500mm (20") from the end of the muffler at 45% when the mean piston speed
is 11m/sec for 4 Strokes and 13m/sec for 2 strokes. The rev range varies according to the stroke of the engine.
A YZ400/426F is meaured at 5500rpm, a typical 2 stroke 250 is measured at 5400 to 5700 and a 125 2 stroke is measured at 7000 to 7200 rpm.

Table of Strokes and RPMS for Various Bikes

We make no recommendations as to what muffler/exhaust system you should purchase. We do however enforce the noise emissions rule and will refuse entry to a machine that fails our noise tests.

Two stroke exhausts that rely on muffler packing for their effectiveness should be regularly repacked to ensure continued compilance.

Thanks to Moorooka Yamaha and Ian Kerr for an extensive testing session on Feb 13th 2001.
If any Distributors or Retailers would like us to test their products please email.

Date last updated, 20th July 2002.