An alternative supplier in the US is WebCams. Their website can be reached by clicking here.

Yamaha XS 650 Twin (68-85) 4v
.395/.395 280°/280° 240°/240° 59 80-070 regrind only
Broad power range for street and touring.

.395/.395 290°/290° 252°/252° 59a 80-080 regrind only
Good mid and upper end performance for hot street. Requires Performance Valve Spring Kit.

.475/.475 302°/302° 266°/266° 84 N/A 80-101 hard weld
Strong mid and upper end performance for racing engines. Requires Performance Valve Spring Kit.

Valve Spring Kit With Aluminium Retainers Fits 1972-1985 VC-Y65
Kit includes performance dual springs Aluminium retainers, and bottom cups. Fits 1972-1985.

Valve Spring Kit With Aluminium Retainers VC-Y64
Kit includes performance dual springs and Aluminium retainers. Fits 1971 and down. OK to .450 valve lift.

Valve Spring Kit With Titanium Retainers VC-Y19
Kit includes performance dual springs and Titanium retainers. Must use shortened valve guides for high lift cams with this spring kit. Fits 1975-1983. OK to .515 valve lift. Price Per Set (4).
Valves, Stainless Intake Standard Size IV-Y19
Standard size 41 mm.

Valves, Stainless Exhaust Standard Size EV-Y19
Standard size 35 mm.

They also has available profiles for the a 270° and 277° cranks.