919 gearing !! - Wrist Twisters
 
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post #1 of 5 Old 12-08-2007, 03:01 PM Thread Starter
 
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919 gearing !!

new 919 runs at 3900rpm in top gear, like a hornet !

changed front drive sprocket 16 to17, now runs at 3850rpm, was expecting lower rpm !!

if l change rear sprok' from 43 to 44, = bigger rear, then that halves the action of the front sprok' ? defeating the purpose !
big rear = more rpm= go slower ?
sml rear = less rpm = go faster ? OR shifting 16/43 up to 17/44 keeps same ratio , but reduces the rpm ???

confused ?........l am !! any info would b great !!

thanks .... blade:

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post #2 of 5 Old 12-08-2007, 03:37 PM
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not sure what you are basing your rpm's on the speedo maybe if so it will read the same as it reads from the eng somewhere and not the front wheel like older bikes.
With the 17/43 it should be reading right as the stock set-up is off at least 10%

Have you been to 919.org yet?He has a nice spreadsheet for gearing there.Have to have execl to read it though.

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post #3 of 5 Old 12-08-2007, 03:59 PM
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To elaborate a little on tvetree's post.

Go to 919.org Select MODS. then select Gearing Spreadsheet. You can plug any # of teeth sprocket into the interactive Excel spreadsheet.

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post #4 of 5 Old 12-08-2007, 06:53 PM
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-1 up front approx = to +2.5 out back

final drive is what matters, hence the spreadsheet

honestly, the 9r has enough torque w/ any gearing setup...riders should focus on tuning the rpm's in their primary cruising range (17/43 16/44)

folks wanting to reduce 1st gear to sheer lunacy may try 15 upfront and 45 out back...crazier than this and u be stuntin'

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post #5 of 5 Old 12-09-2007, 05:21 PM
 
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Quote:
Originally Posted by BLADE RUNNER View Post
new 919 runs at 3900rpm in top gear, like a hornet !

changed front drive sprocket 16 to17, now runs at 3850rpm, was expecting lower rpm !!
Are you comparing the RPM to Speedometer relationship? This will not change regardless of gearing.

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