To secure, by a simple structure, air tightness with a piping member fitted to a tubular shaped cylindrical part for piping connection provided on a body for a scavenging valve in a carburetor for stratified scavenging.
A circumferential groove 13 is formed over the all circumference of a tubular extension 8a of the body 8 for the scavenging valve, a side wall surface 13b on its one side is formed in a slant face and a rubber boot 9 fitted to the tubular extension is installed with an inward ridge 9a of the rubber boot merged in the circumferential groove. The circumferential ridge of the elastic piping member is received in the circumferential groove formed in the outer peripheral surface of the tubular extension to form a labyrinth seal structure with respect to an air flow of air leakage. Furthermore, the circumferential ridge is pressed in the circumferential groove by fastening a fastener member, for instance a band, and as the circumferential groove is formed to be narrow toward a groove bottom, the circumferential ridge is resiliently deformable while being pressed in, so that a close contact force between the circumferential groove and the circumferential ridge in increased and the air tightness can be further enhanced.
AIHARA TAMIO
MICHIYAMA SACHIAKI
MIYAKI HIROYUKI
KAWAMURA KUNIMUNE
KIORITZ CORP
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