Document ID: chunk:federal_register_of_legislation:F2021C00509:front:0:p53
Version: federal_register_of_legislation:F2021C00509
Segment Type: other
Provision Reference: 
Character Range: 152800–155105

exhaust gases is alternatively interrupted and restored 2,500 times by a rapid-action valve.

           1.3.2.3. The valve must open when the exhaust gas back-pressure, measured at least 100 mm downstream of the intake flange, reaches a value of between 0.35 and 0.40 bar. Should such a figure be unattainable because of the engine characteristics, the valve must open when the gas back-pressure reaches a level equivalent to 90% of the maximum that can be measured before the engine stops. It must close when this pressure does not differ by more than 10% from its stabilized value with the valve open.

           1.3.2.4. The time-delay switch must be set for the duration of exhaust gases calculated on the basis of the requirements of paragraph 1.3.2.3.

           1.3.2.5. Engine speed must be 75% of the speed (S) at which the engine develops maximum power.

           1.3.2.6. The power indicated by the dynamometer must be 50% of the full-throttle power measured at 75% of engine speed (S).

1.3.2.7. Any drainage holes must be closed off during the test.

           1.3.2.8. The entire test must be complete within 48 hours. If necessary, a cooling period must be allowed after each hour.

    1.3.2.                                        CONDITIONING ON A TEST BENCH

           1.3.3.1. The exhaust system must be fitted to an engine representative of the type fitted to the motor cycle for which the exhaust system was designed, and mounted on a test bench.

           1.3.3.2. Conditioning consists of the specific number of test bench cycles for each class of motor cycle for which the exhaust system was designed. The number of cycles for each class
           of motor cycle is:

Class of motor cycle                   Number of
according to cylinder capacity in cm3  cycles
    Class I  < 80                      6
    Class II  > 80 < 175               9
    Class III  > 175                   12

           1.3.3.3. Each test-bench cycle must be followed by a break of at least six hours in order to reproduce the effects of cooling and condensation.

           1.3.3.4. Each test-bench cycle consists of six phases. The engine conditions for and the duration of each phase are:

Phase               Conditions           Duration of phase
Engines < 175 cm3   Engines > 175 cm3