CHASSIS8-9EAM20119CHASSISEAM30168SELECTION OF THE SECONDARYREDUCTION RATIO (SPROCKET)reduction ratio>• It is generally said that the secondary gear ratioshould be reduced for a longer straight portionof a speed course and should be increased fora course with many corners. Actually, howev-er, as the speed depends on the ground condi-tion of the day of the race, be sure to runthrough the circuit to set the machine suitablefor the entire course.• In actuality, it is very difficult to achieve settingssuitable for the entire course and some set-tings may be sacrificed. Thus, the settingsshould be matched to the portion of the coursethat has the greatest effect on the race result.In such a case, run through the entire coursewhile making notes of lap times to find the bestbalance; then, determine the secondary reduc-tion ratio.• If a course has a long straight portion where amachine can run at maximum speed, the ma-chine is generally set such that it can developits maximum revolutions toward the end of thestraight line, with care taken to avoid the en-gine over-revving.TIPRiding technique varies from rider to rider andthe performance of a machine also vary frommachine to machine. Therefore, do not imitateother rider’s settings from the beginning butchoose your own setting according to the level ofyour riding technique.EAM30169DRIVE AND REAR WHEEL SPROCKETSSETTING PARTSEAM30170TIRE PRESSURETire pressure should be adjusted to suit the roadsurface condition of the circuit.• Under a rainy, a muddy, a sandy, or a slipperycondition, the tire pressure should be lower fora larger area of contact with the road surface.• Under a stony or a hard road condition, the tirepressure should be higher to prevent a flat tire.Secondary reduction ratio = Number ofrear wheel sprocket teeth/Number ofdrive sprocket teethSecondary reduction ratio3.846 (50/13)Part name Type Part numberDrivesprocket “1” (STD) 13T 9383B-13218Rear wheelsprocket “2”47T 17D-25447-5048T 17D-25448-5049T B2W-25449-00(STD) 50T B2W-25450-0051T B2W-25451-0052T 17D-25452-50Standard tire pressure100 kPa (1.00 kgf/cm², 15 psi)Extent of adjustment60–80 kPa (0.60–0.80 kgf/cm², 9–12 psi)Extent of adjustment100–120 kPa (1.00–1.20 kgf/cm²,15–18 psi)Part name Type Part number
