Great pix, GF!
About the shoulder of the 530 Honda sprocket (above) that sticks out past the end of the shaft: it appears that the offset of parallellism to the rear sprocket would be 1/2 of the extra shoulder width of one side, or about 1mm. That part, at least, is well within factory alignment specs (4mm) for a new setup. Making the retainer washer fit might be a different issue, though.
And, that will raise this issue, to watch for: most "standard" sprockets have square-cut tooth tips, per ANSI requirements. But, on these bikes (for a variety of reasons), the teeth tips MUST be tapered. Honda sprockets are always cut with tapered tips. This greatly eases the entrance and exit misalignments (and related noise and wear) that occur from the high torques this mechanical system sees. The tapered tooth guides the chain to settle into the radius, rather than just crashing it into place. This puts more torque to the rear sprocket, and affects handling less, too (a slightly different, but related, topic).
745: how is the rear sprocket different on the 77-78 bikes? Is there a longer shoulder on the sprocket hub, to space the face outward?
On the original "K" series, the back side of the rear sprocket is flat, and the front is recessed to allow for the tin "grunge guide" to fit within the rear axle's span. So, when flipping the rear sprocket (to get that last 10,000 miles out of it), a spacer plate is needed (I've used a pair of cut-down "grunge guides" for years for this purpose) to space the teeth outward, and the "grunge guide" should be removed while the sprocket is run flipped. Technically, you can still run with the "grunge guide" in place, but the pinch points for flying debris can potentially get dicey then. I've done it with no ill effects. Honda does not recommend the "sprocket flip" practice, though, for obvious reasons.
Details on Honda's own sprockets:
1. Teeth are always tapered to ease side-loads and noise, reducing wear and increasing HP at the ground.
2. The shoulders are wider (speaking of 530 sprockets here) to prevent heating of the splines. This occurs under high-torque moments, when the engine is accelerating hard in the lower gears. Just 10% wider splines will reduce the heating almost 50%, and Honda's shoulders are almost 25% wider than the sprocket teeth. This issue stems from a smaller-than-recommended (by ANSI) shaft size for a 100 HP 530 sprocket setup like this one. (A relatively minor goof on the part of the 750 engine designers, who wanted to use 450 parts as much as possible...). The original 16T/45T sprockets on the K0 did NOT have shouldered sprockets up front, and the shaft wore quickly: I think there is even a Service Bulletin about this problem. (But, this is how we Honda wrenches got to see inside the 750 for the first time!)
3. Honda's sprockets do not grip the output shaft tightly, thus allowing room for lube to get inside. This occurs when the engine accels or decels, when the sprocket tilts toward the outside in opposite directions, wicking in some oil/grease from the area. If yours is rusty or dirty, clean this interface well, even apply a little grease, when reassembling.
Finally: what does a completed conversion look like on the K7/K8? Anyone have finished pix?
