chain sprocket ratios

[PostmanPete]

Hey guys and gals, merry xmas and happy new year. My question is what is the standard front/rear sprocket ratio on a gen 1 (04) I think mine has been changed as my speedo seems to be WAAAY out 110km highway speed indicating roughly 130-40kmh! so I figure if I change back to original at least it will be closer? I realise they are not spot on even when new 8-10% quite often. I,m not interested in having ballistic excelleration because in standard trim the Busa has that already so going back to standard is not an issue. One thing I havent done is check the current sprockets but Iam confident they are not standard. It needs a new set soon thats why the question. One last thing where does the speedo get its info from (RPM?). Cheers Bartman

Hiya Bartman,
Speed info is taken from front sprocket, if you look above and forward of your lh peg you'll see a wire with a plug bolted in to the sprocket cover. All becomes obvious when you remove this cover. As Kev said, std gearing is 17/40. I've got 18/40 gearing on mine, and it's only a bees dick out. (With a 190/50/17 tyre)

Cheers