Service Procedures: Notes
"Open" crankcase ventilation system should be serviced every 9, 000 miles. At this interval, the breather cap should be cleaned with solvent, then remove the crankcase ventilation regulator valve, exhaust tube, and connections. Clean the valve and exhaust tube in clean carburetor solvent and dry them with compressed air. Clean the rubber hose connections with a low volatility petroleum base solvent and dry them with compressed air.