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Old 08-31-2011, 07:20 PM   #31 (permalink)
Stick your neck out...
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Join Date: Jun 2011
Location: Essex UK
Posts: 135
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Thanked 67 Times in 37 Posts
Patrick - that would be a neat idea, a twin range gearbox! I had no idea it even existed, do you have any info or images?
I know I'm short on ratios - the standard gearbox is three speed, and I realise that acceleration will always be the weak point but here is what I planned.
The stock C90 is ridiculously low-geared, I often found it better to get off the line in 2nd, and at no time have I ever been more than 10mph in first. I did all the gear calcs and found that my 1st gear gives 2.2mph per 1000rpm and 2nd gear gives 3.8mph per 1000 rpm.
The new system (jackshaft & Z750 rear-end) gives 3.1mph per 1000 rpm (first gear) and 8.3mph per 1000rpm in top. This means I'm comfortable getting off the line (as its no worse than I'm used to) and the top speed goal can be reached with a slight increase in max revs from 10500 to 12100. I'm confident the rebuilt engine will manage this with ease.
Thanks for links to engine parts - if you see any more let me know

jkv357 = it's a tough challenge alright, and I didn't expect to be popping any wheelies. but I ran the numbers through the calculator tool provided on the forum and it confirmed the possiblity. The link is Cd=.19&FrontalArea=.7&FrontalAreaUnits=m^2&FuelWh= 33557&IceEfficiency=.21&DrivetrainEfficiency=.90&P arasiticOverhead=0&rho=1.22&FromToStep=5-200-5

Thanks again - all thoughts welcomed

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