CYLINDER HEAD TO BARREL SLEEVE NUT, CLOSED

A3/156: 2 3/32" (53MM) UNDER THE HEAD, BLIND, STAINLESS  
ALSO SEE:
CHSNM: 2 3/4" (70MM) UNDER THE HEAD, THRU DRILLED, STAINLESS
CHSNL: 3 1/8" (79MM) UNDER THE HEAD, THRU DRILLED, STAINLESS
CHSNS: 2.4" (61MM) UNDER THE HEAD, THRU DRILLED, STAINLESS


PLEASE CHECK DIMENSIONS ABOVE TO ENSURE YOU ORDER THE CORRECT SIZE FOR YOUR BIKE. PLEASE NOTE ALL SLEEVE NUTS ARE THE SAME THREAD 3/8" X 26TPI

PRIOR TO 1936 THE ROCKER GEAR WAS OPEN AND THE DESIGN WAS DIFFERENT WITH THREADS AT BOTH END AND TWO HEXES LIKE THE INTERS. THE TOP THREAD HELD THE ROCKERS DOWN. WE HAVE NOT AS YET MADE THIS NUT.
FROM LATE 1936 ONWARDS PART NUMBER A3/156 ARRIVED, THIS WAS THE SHORTEST OF ALL AND THE ONLY ONE THAT WAS BLIND AND DID NOT ENGAGE WITH THE FINS IN THE CYLINDER BARREL. IN 1948 THE 500T ARRIVED WITH THE ALFIN HEAD, THIS HAD A LONGER NUT ON PART NUMBER D3T/156 THIS ENGAGED WITH THE CYLINDER BARREL AND HELPED LOCATE THE HEAD.
IN 1956 THE ROAD BIKES GOT THE ALFIN HEAD. IN 1957 THE M50 IS SHOWN AS 19842 THE ES2 AND 19 SHOWN AS C126. FROM 1959 BOTH THE ES2 AND M50 USED THE C126, IT IS QUITE CONFUSING AS MANY BIKES ARE NOT ORIGINAL AND THERE IS ALSO A CHOICE OF STUD LENGTH SO WHAT I HAVE DONE IS COLLECTED UP ALL THE OLD SLEEVE NUTS I HAVE AND MEASURED THEM WE ENDED UP WITH FOUR TYPES. AS THE ONLY PART NUMBER I AM CERTAIN OF IS A3/156 THE OTHER THREE ARE NUMBERED THUS.....
CHSNL (CYLINDER HEAD SLEEVE NUT LONG) THERE IS ALSO SHORT (CHSNS) AND MEDIUM (CHSNM)

ADDITIONALLY WE STOCK THREE DIFFERENT LENGTHS OF THROUGH STUD. THE THREADS ARE IDENTICAL ON ALL THREE STUDS AND THE LENGTH QUOTED IS APPROXIMATELY THE LENGTH LEFT PROTRUDING FROM THE CRANKCASE ONCE THE STUD IS FITTED.

19840        5 3/8" AND THE OVERALL LENGTH IS 6 5/16"
19841        5 3/4" AND THE OVERALL LENGTH IS 6 5/8"
18638        6 5/16" AND THE OVERALL LENGTH IS 7 3/16"