11. FUEL SYSTEM STRYKER 125/150 Remove the spring and vacuum diaphragm/ Spring piston. Vacuum Diaphragm/Piston Remove the needle holder and jet needle. Be careful not to damage the vacuum diaphragm. INSPECTION Jet Needle Inspect the needle for stepped wear. Inspect the vacuum piston for wear or damage. Inspect the diaphragm for deterioration and tears. Vacuum Diaphragm 11-8