speedo MPH compared to GPS MPH ,15/40 .520 - Honda RC51 Forum : RC51 Motorcycle Forums
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post #1 of 6 (permalink) Old 11-26-2011, 05:10 PM Thread Starter
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speedo MPH compared to GPS MPH ,15/40 .520


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Last edited by rc51anthony; 03-21-2012 at 08:12 PM.
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post #2 of 6 (permalink) Old 11-26-2011, 06:18 PM
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I got 3 bikes ..and all 3 of them ...the speedo is of by 7 -10 miles
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post #3 of 6 (permalink) Old 11-26-2011, 07:04 PM
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Originally Posted by rc51anthony View Post
SO I HAVE A 520 CONVERSION , with stock gears 15/40 ,,, at 4500rpm the speedo shows 88 mph . but my gps shows 78 mph , , so even that the gears are stock number , with the 520 the unsprung weight is that much less , that the speedo is 10 mph off ,, ??? i hope you understand what im saying here ,
I believe stock gearing is *16*/40 so that's one reason your indicated MPH is too high. When I swapped from 16/40 to 15/41 I had to adjust my speedo by 17% to make it accurate. With stock gearing the speedo was off by about 7%...
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post #4 of 6 (permalink) Old 11-26-2011, 07:40 PM
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Yep, stock is 16/40. I went with 15/41 and had to adjust my calibrator too.

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post #5 of 6 (permalink) Old 11-26-2011, 08:02 PM
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post #6 of 6 (permalink) Old 03-22-2012, 04:29 PM
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you could grab a speedohealer....mine came in yesterday and changing down by 14.2% mine reads perfect speed now...and it has a cool mountable button that shows you your top speed you've hit
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