Looking for land speed tips - Honda RC51 Forum : RC51 Motorcycle Forums
 
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post #1 of 5 (permalink) Old 10-19-2014, 09:14 PM Thread Starter
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Looking for land speed tips

Evening!

I'm currently building my 03 rc51 from the ground up and got the itch to take to to El Mirage or Bonneville next year to finally have some fun with land speed events. I have a few buddies that go every year with their knucklehead & 29 harley's.

I thought I saw someone on here that did this with their rc and was looking for any input on gearing and such.

Thanks!
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post #2 of 5 (permalink) Old 10-20-2014, 02:13 PM
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The enemy of speed is aerodynamics.
When the wind resistance balances power, you hit the wall.

Wind resistance increases with the cube of the speed, so you double your speed, you triple your wind resistance.

Even stock, the final drive ratio was too tall on the RC51.
By reducing the final drive ratio, the engine was able to operate in its optimal power band.
But that also reduces its mathematical top speed.

On the plus side, the RC51 was quite aerodynamic amongst Honda product line of the time.
Even with less HP, it was able to attain the same speed as the CBRs due to less wind resistance.
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post #3 of 5 (permalink) Old 10-20-2014, 02:23 PM Thread Starter
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Thanks for that! The I was going to run sharkskinz track fairings and windscreen to allow me to fully tuck behind it.

I'd like to earn a 150mph hat. I was just wondering what's a good gearing to start off with.
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post #4 of 5 (permalink) Old 10-20-2014, 05:32 PM
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I'm pretty even a 100% stock can do 150. Thats not much of a challenge for a modern sportbike. Gearing should not be an issue. I've done that 15/41 with 190/55, GPS corrected speedo.

But for extreme top end, get the bike dyno'd to find out where your power band is then play around with gearing until you are in that RPM range at your higher (almost top) speeds.
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post #5 of 5 (permalink) Old 10-20-2014, 09:17 PM Thread Starter
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Thanks James! That was my thought to, that a down and back above 150 shouldn't be tough. I still need to be become friends with a dyno tuner here in phoenix.

I appreciate the input!
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