Patent ID: 7681680

Claim:
A frame assembly for a motorcycle, the frame assembly comprising: a head pipe for supporting a front wheel suspension at a front end of the motorcycle, a unitary leading frame portion integrally attached to and extending rearwardly from said head pipe, said unitary leading frame portion formed as a closed rectangular tube when viewed in cross-section, and a rear frame portion for supporting a rear wheel suspension, said rear frame portion extending substantially downwardly from a rear part of said leading frame portion, the rear frame portion having recessed portions opened in leftward and rightward directions and comprising integrally formed pivot support sleeves projecting in the leftward and rightward directions, such that the rear wheel suspension is supported by the pivot support sleeves; wherein the frame assembly comprises a first component part and a second component part, said first and second component parts arranged serially in a front-to-rear direction of the motorcycle, the first and second component parts being cast from an aluminum alloy; wherein the first component part comprises the head pipe and the leading frame portion, and the second component part comprises the rear frame portion, wherein the leading frame portion comprises a small section portion which provides a part of the leading frame portion having the smallest sectional area, the small section portion disposed medially in the longitudinal direction of the leading frame portion, and wherein the first and second component parts are coupled together at a portion of said frame assembly located behind said small section portion, wherein a coupling portion is formed between the first component part and the second component part.