1975 Harley-Davidson SS-250 | HowStuffWorks One of a quartet of new mid-size two-stroke singles based on a Yamaha design and introduced by Harley-Davidson in the mid-1970s, the SS-250 appeared in 1975 and was the largest street version offered. On/off-road models carried the SX prefix, and both bikes were eventually available in 175- and 250 Author: The Auto Editors of Consumer Guide 1975 harley ss250 | eBay Find great deals on eBay for 1975 harley ss250. Shop with confidence. Skip to main content. eBay Logo: VTG 1975-78 HARLEY DAVIDSON AMF SX SS 250 Engine MOTOR Carburetor AERMACCHI . Pre-Owned. $475. or Best Offer. Free Shipping. NOS Harley Aermacchi 1975-1978 SS 250 Saddlebag Mounting Kit 90950-76 See more like this.