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Gear ratios
andyd - 15/2/03 at 05:46 PM

Ok so we've got our 'blade engine and we are looking to find a company nearby to make up a suitable prop and we also have a nice new haynes manual but we know nowt about how a bike g/box works.

Well ok that's not strictly true 'cause we ain't dummies but the question that we have is...

If the 6th gear ratio is 1.167 : 1, does this mean that for one engine revolution the sprocket revolves 1.167 times? The reason for our confusion on this is that my CBR600 manual talks of a primary reduction ratio and a final reduction ratio. What the dickens are they and how do they affect the situation?

We are trying to ascertain the top speed revs etc based on particular wheel/tyre combos.

[Edited on 15/2/2003 by andyd]

Macca - 15/2/03 at 06:16 PM

Check your U2U

Col

andyd - 15/2/03 at 06:21 PM

Col,

Check your U2U

Macca - 15/2/03 at 06:29 PM

Andy,
Check your email
Col

Rorty - 16/2/03 at 01:47 AM

I'm not sure if you love birds have resolved the issue through U2U.
The following rant may shed a little light anyway.
With bike motors, the clutch/gearbox is gear driven from the crankshaft (the primary drive). So, your 6th gear ratio of 1.167:1 is multiplied by your primary ratio (which should be specified in the manual too), to arrive at the "real world" gear ratio (engine revs to output shaft revs).

andyd - 16/2/03 at 10:38 AM

quote:
Originally posted by Rorty
I'm not sure if you love birds have resolved the issue through U2U.


Thanks Rorty, all sorted.

Unfortunately, the Haynes manual doesn't actually specify the primary reduction ratio but I've seen 1.52:1 quoted on someone else's website for a '97 engine and the one that we have is '96 (same spec) so I'm going with that.

Thanks again guys.

Jon Ison - 16/2/03 at 11:06 AM

may be of help, may make it like mud, but..............

i run a 893cc blade,

3.89 diff
15" 50 profile tyres
good for 130mph in top............