Flapper and Pair valve Mod ? - Honda RC51 Forum : RC51 Motorcycle Forums
 
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post #1 of 6 (permalink) Old 07-16-2009, 09:21 AM Thread Starter
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Flapper and Pair valve Mod ?

If I do these mods, will I have to remap?
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post #2 of 6 (permalink) Old 07-16-2009, 09:30 AM
 
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I have done these mods. Not had to remap.
I would rec though.
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post #3 of 6 (permalink) Old 07-16-2009, 10:36 AM
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The flapper is nice, and it smooths out the dip in power that is seen when the flapper actuates, but I have not seen any proof that the PAIR mod does anything to help the bike, other than it cuts down on backfiring.

People claim the pipes are cooler and that there is "better exhaust scavenging", but those 2 statements are contradictory. Hot exhaust gases flow faster due to the expanded nature of the molecules. If exhaust gas goes from a hot environment (the combustion chamber) to a hotter environment (the pipe), the gas will expand and flow. If the pipe is cooler, the gas will condense and tend to pack up.

So, if the pipe runs cooler, then the plus for PAIR is a cooler running bike with less power. If the pipe runs hotter, then the plus for PAIR is just more power through better scavenging.

Which is it? SubSailor? If anybody knows, you do.

Eric
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post #4 of 6 (permalink) Old 07-16-2009, 01:16 PM Thread Starter
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I've done the pair valve mod on my VTX when I had it. It did nothing for power. Just basically cleaned the motor area up. I (assume) the same applies for the RC51. The flapper mod sounds like the one I'd like to do first. But if I'm gonna order plates to block it off, then I'll just order plates for the pair mod too and do it all at once.

Is there a site where I can down load a map? The one i have in there now is a custom map.
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post #5 of 6 (permalink) Old 07-18-2009, 07:13 PM
 
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Not that I know of. If you take the pair and flapper out you will loose about 2.25lbs from the bike. I put my on a scale b4 and after the mods. I also removed all the foam from around the air box.
A ? I have is how much better would a PC do to a stock rc? I have a prob with the bike sputter when around 120 deg when I take off from a stop.
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post #6 of 6 (permalink) Old 07-18-2009, 07:48 PM
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The main advantages of removing the PAIR system is less weight and tendency to pop on deceleration.
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