Yamaha XS 650
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The Yamaha XS 650 was produced from 1970 into the 1980s for the worldwide motorcycle market. In the United States, the last model year was 1984.
The XS 650 is powered by an upright, parallel twin four-cycle motor firing every 360° of crank rotation.
The 1970 model was designated the XS-1. Subsequent models were XS-1B (1971), XS-2 (1972), then they changed the model designation from XS to TX. It went TX (1973), TX-A (1974), then they changed it back to XS but went on with the alphabetical suffix. XS-B (1975), XS-C(1976), XS-D(1977), XS-E (1978), XS-F (1979). 1979 was the last year of the so-called "Standards" (owner's term meaning opposite to Special) The Es and Fs also came in Special form; XS-SE (S for Special) and XS-SF. From then on it was Specials only to XS-SJ.
All wheels (chrome rim wire, aluminum rim wire, seven-spoke cast aluminum) swap on all years.
Except that:
- Drum fronts on early models are on their own.
- Pre '77 & post '77 fronts have different (offset) brake disks, the wheels swap but not the disks.
- Drum rear wheel into rear disk frame needs the rear drum frame swingarm too.
- Disk rear wheel into rear drum frame needs the rear disk frame swingarm and also needs brake master-cylinder lugs welded to the frame.
Handling differences on swapping rear wheels:-
- Standard rear tire is 110/90-18. Special rear tire is 130/90-16. Because the Standard tire is narrower it corners quicker. Because the Special tire is wider it's steadier in a straight line. Overall gearing will not change as the two tires are essentially the same outside diameter.
- Left-side front disk brake (omitted on North American models only) can be added by bolting another disk to the left side of the wheel (the bolt holes are there) and the left-side caliper from an SR500, XS750, XS850 or XS11 (the fork lugs are there) and adding the other brake line & a double-length banjo bolt. XS650 stock master cylinder still works. The system needs very careful bleeding, stainless steel wire braid hoses improve the feel.
Standard (large) and Special (small)gas tanks interchange but must keep their own gas caps because they are different.
Mid-'77 the front forks had a major redesign, fork tube diameter increased from 34 to 35 mm and internals were changed (although this also holds true for various years of the same tube size). The entire fork assembly (with triple tree) will swap either way but fork parts are not equivalent. Also the brake caliper changed from a 48mm dual piston cast iron design for the 34mm fork to a 40mm aluminum single piston floating caliper for the 35mm forks. The brake caliper mounting lugs on the fork sliders are of different spacing for the 34mm and 35mm forks so the calipers can't be swapped.
