2006-2009 Suzuki LT-R450 Service Manual, Page 213Get this manual
COOLING AND LUBRICATION SYSTEM
RADIATOR CAP INSPECTION
Remove the radiator cap CD from the radiator Fit the cap CD to the radiator cap tester (2) Build up pressure slowly by operating the testerMake sure that the pressure build-up stops at 108137 kPa (1.081.37 kgfcm2, 15.419.5 psi) and that, with the tester held standstill, the cap is capable of holding that pressure for at least 10 seconds Replace the cap if it is found not to satisfy either of these two requirements
Radiator cap valve opening pressure Standard: 108137 kPa (1.081.37 kgfcm15.419.5 psi)