DS5-E, YDS-5, DS6 and DS7 Names
Yamaha's official collection identifies the 1967 production motorcycle as DS5-E and describes it as the successor to the YDS series, while period Yamaha material also uses the YDS-5 name. Yamaha then documents the 1969 DS6 as a distinct 250-class two-stroke twin and separately identifies DS6-C as its scrambler variation. The DS7 appears in Yamaha's 1971 material and in Yamaha USA's 1972 parts catalog. Use the full model, market designation and year rather than treating every DS or YDS spelling as interchangeable.
The current DS-tagged inventory contains a 32 x 44 x 10.5 mm fork seal listing for DS5-E/YDS-5 and DS6 applications, plus a separate 34 x 46 x 10.5 mm listing for DS7. The Suzuki DS185 tag on one shared product is unrelated to this Yamaha family and is not counted as a Yamaha DS model.