See, that's what doesn't make sense. Four degrees at the crank is 4 at the crank, period. There are only 2 reference points - crank and cam, you're measuring degrees different between them. Now 4 degrees diff between crank & cam translates into roughly 2 degrees off at the IP, since it's more or less in the middle, but we're not discussing the IP timing and I'll leave that alone for the sake of simplicity at this point. I went and measured the distance between teeth on the sprocket (chain link), and it's about 9.4mm. However we'd need the distance relatlive to the circumference on the two different arcs, one at the key radius, one at the chain radius, to make the numbers in the FSM mean anything. (I was slightly confused until I realized that.
)
So, I think the only way to tell if an offset key moves 2-5 degrees (like the EPC says) or 4-10 degrees (like the FSM says), is if we can find someone who has personally done this - AND took notes to determine the difference in crank/cam offset that was obtained with which particular part number of the 4 available offset keys. Sheesh, I think I'd just change the silly chain.
On a side note, my 617 has never had the chain stretch checked. I hope to yank the cover off and find out soon. If it's enough to warrant a new chain, I might pick up one offset key to play with (they're about five bucks wholesale) and put an end to the debate. Sure would like to hear from someone who's BTDT though!
