OFF THE WIRE,
Current federal regulations require all new on-highway motorcycles sold in
the U.S. to emit no more than 80 dB(A) as measured at 50 feet during a
pass-by test of the motorcycle under very specific acceleration parameters.
The regulations also require the motorcycle exhaust system to carry a
permanent stamp that identifies the exhaust system as compliant with federal
regulations for the specific year, make and model motorcycle on which it is
installed. You can find these regulations in 40CFR205 subparts D & E,
copies of which I have attached to this message.
In practice, as written the federal regulations require OEM (original
equipment manufacturer) replacement parts on virtually all on-highway
motorcycles built since model year 1983, as only two after-market
manufacturers (BUB Enterprises and Vance & Hines) build labeled exhaust
systems for certain late-model Harley-Davidsons. Is it fair to require an
owner to scrap his or her motorcycle because they can't obtain a
factory-replacement exhaust system? We don't think so.
After all, the issue is excessive noise, not a label on the exhaust system.
That's where the SAE J2825 comes into play.
The J2825 recommended practice recommends two testing procedures. The
first, an idle test, establishes a maximum sound level of 92 dB(A) for an
on-highway stationary motorcycle at idle, regardless of the number of engine
cylinders. A 2 dB(A) 'bonus' (max level of 94 dB(A)) is established for
motorcycles with U.S. EPA compliant (i.e., labeled) exhaust systems. The
second, called a set RPM test procedure, establishes a maximum sound level
of 100 dB(A) at 5,000 RPM for 3 or 4 cylinder engines and 96 dB(A) at 2,000
RPM for all other engine configurations. Alternately, if a motorcycle
cannot maintain a constant 2,000 or 5,000 RPM reading, a swept test
procedure (gradual increase to specified RPM level) is permitted.
We support the SAE J2825 recommended practice because it's practical,
reliable, and follows the lead established by the SAE for measuring
off-highway vehicle sound using the J1287 recommended practice.
Again, if the issue is excessive sound, we can't think of a better way to
establish a test procedure that's fair to all concerned (i.e., motorcycle
owner, law enforcement, courts, etc.) than this one.
Question/Comment: Why would changing the current fed law regarding the
measurement of decibels to J8825, be beneficial to motorcylists? It appears
this would only benefit law enforcement
