In this study, exhaust emission measurement was carried out in a fleet of twelve
two-stroke motorcycles of different capacities, model years and manufacturers and
four units of four-stroke motorcycles of capacity size ranging 98–110 cc. The test
motorcycles were from Yamaha, Kawasaki, Suzuki and Honda manufacturers and
classified into two groups. The first group is new motorcycles which have a mileage
of 1000–20 000 km and the second group is old motorcycles which have a mileage
of more than 20 000 km. The engine and oil tank of the two-stroke motorcycle
were cleaned to remove old fuel, auto-lube oil and any deposits and refilled with
super unleaded gasoline and low smoke lube oil. Each motorcycle was triplicately
sampled for exhaust emissions. An initial sampling began at the start of the program
and followed by duplicate test after the motorcycle had driven to an addition
of 1000 and 2000 km, respectively. The following two sampling methods are used
in this study: