DUFF NOTOR VALVE MADE IN THE USA
THE DESIGN OF MOST INDIAN ENGINES WAS INSTIGATED INTHE ROARING TWENTIES AND MOST OF THE ROAD CONDITIONS WERE PRETTY POOR RIDING ON DIRT ETC. CONSEQUENTLY THE ENGINE WAS NOT WORKED AS HARD AS PERHAPS IT IS NOWADAYS. SPEEDSOF 40-50 MPH WERE [PRETTY UNCOMMON ALTHOUGH AS WE KNOW THE INDIAN MOTOR CAN ACHIEVE THIS AND A LOT MORE. INDIAN USED A SYSTEM OF CONSTANT UPGRADES TO KEEP UP WITH NEW TRENDS DESIGNS AND NEW MATERIALS HOW EVER THE BREATHING SYSTEM DID NOT CHANGE VERY MUCH AFTER THE BIG CHIEF.
ONCE YOU START TO WORK THESE ENGINES HARD AND AT HIGHER REVS AND ROAD SPEEDS THE ENGINES CAN TEND TO BREATH HEAVILY AND THIS MANIFESTS ITSELF IN A NUMBER OF WAYS BUT IN PARTICULAR HEAVY BREATHING THROUGH THE INDIAN BREATHER VALVE, HIGHER FUEL CONSUMPTION AND LEAKS FROM AROUND THE CRANKCASE AS THE INTERNAL CRANKCASE PRESSURE IS CONSTANTLY KEPT HIGH. OF COURSE WE KNOW THAT WE NEED SOME INTERNAL CRANKCASE PRESSURE TO MAKE THE ENGINE FUNCTION BUT TOO MUCH CAN BE DETRIMENTAL. SOME ENGINES ARE PARTICULARLY BAD AND HAVE QUITE A BIG PROBLEM WITH SPOTTING OIL AFTER A HARD RUN.
THE DUFF MOTOR VALVE IS A NEW MORE MODERN DESIGN OF BREATHER VALVE. IT HAS A HIGHER FLOW THRU THE VALVE THIS WILL RELIEVE THE INTERNAL CRANKCASE PRESSURE ALLOWING BETTER FLOW OF AIR ON THE DOWNWARD STROKE RELIEVING INTERNAL CRANKCASE PRESSURE ALLOWING THE MOTOR TO REV MORE FREELY AND WORK LESS HARD.
THE BENEFITS ARE:
REDUCED SPOTTING AFTER A HARD ENGINE RUN
BETTER FUEL CONSUMPTION
BETTER PERFORMANCE.
ESSENTIALLY YOU REPLACETHE STANDARD BREATHER WITH A DUFF MOTOR VALVE YOU WILL NEED TO SOLDER SOME COPPER PIPE TO THE OUTLET AND GET SOME P CLIPS TO CLAMP THE OUTLET PIPE.
Crankcase Breathing! Duff s Moto Valve Page
Go here for updates from the testers! Updated! 10.4.99
There has been much talk about Indian engine breathing on the mailing lists. Not the breathing the engines do through carburetter, valves and exhaust pipe, but the kind that goes on below the pistons; in & out through the crankcase breather valve. (There is a good article on general engine breathing here)