Click Here to reference Sportster VIN Information in the History section of the Sportsterpedia.

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A bend in the frame backbone on the right above the motor mount bolt is on most L1973-1976 Sportster frames and does appear to be factory induced.
It has been believed to be for easier access to the motor mount bolt but the petcock hangs down close in that area also and the petcock had a few part numbers changes from 73-76.

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