Kinsler Diaphragm High Speed Bypass Valve With Jet Restrictor (KIN-3904)KIN 3904 HIGH SPEED BYPASS REST JET Suit Petrol & Methanol With 6 AN Male Inlet & Outlet Part Number: KIN 3904 The advantage of this valve over the "jet can" type used in the past is that it has less internal friction on it's moving parts, and it has a much larger area from the pressure to act on for regulation, resulting in a valve that opens at the same RPM every time. Easily adjusted using a blade screwdriver and a 7 16" spanner; no parts to drop