Koso Performance Camshaft Honda Grom The Koso High Performance Camshaft enhances engine performance at high RPMs. This cam is a great compliment to the Koso Big Bore Kit, yet it also boosts the performance of engines with stock displacement. Specifications: Duration at 1mm In: 230 Ex: 230 Valve lift In: 0.8mm Ex: 7.5mm Lobe center In: 105 Ex: 105 Running clearance In: 0.08mm Ex: 0.20mm