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Discussion Starter #1
Just performed the flapper mod step by step off the rc51.org website. Now when I start my bike the fuel injection light blinks slowly. Do I need to plug the sensor in the snorkel as well as the solenoid back in?

Thanks,
Bret
 

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When you do the flapper mod you can literally unplug and remove everything associated with the flapper valve and throw it away. The solenoid is not in the diagnostic loop of the ECU during start-up.

The one thing that has to be done is the one vacuum line that routes back to the throttle body ABSOLUTELY HAS to be plugged to keep air from leaking into the throttle bodies.


Now if you removed or unplugged any other sensors while doing the mod then of course those need to be reconnected and would also cause a MIL fault code to present itself.
 

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Discussion Starter #3
I think it was refers to as the BARO sensor. Does that need plugged in? I will also find a different plug for the hose maybe it's not sealing it all the way.
 

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The BARO sensor is on the snorkel, the MAP sensor is on the throttle body (same sensor type, just different use).
Both sensors must be connected for proper operation.
The BARO sensor measures inlet air pressure, while the MAP sensor measures intake manifold pressure.
Together they're used to calculate injector timing for fuel delivery.
The engine will still run, but as well as it could.
 

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When you do the flapper mod you can literally unplug and remove everything associated with the flapper valve and throw it away. The solenoid is not in the diagnostic loop of the ECU during start-up.

The one thing that has to be done is the one vacuum line that routes back to the throttle body ABSOLUTELY HAS to be plugged to keep air from leaking into the throttle bodies.


Now if you removed or unplugged any other sensors while doing the mod then of course those need to be reconnected and would also cause a MIL fault code to present itself.
Was it you that put up the How To for that flapper mod? If so, thanks! I used it early on in my RC51 rebuild. Along with tons of other info on that Mods page.
 

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Ahhhh, I thought that was you. Well, that Mods page has been refered a thousand times in the last year I've been here! Thanks for keeping it up and accessible to all. I've spent many hours there myself pouring thru all the info.
 

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I've already stopped taking new members and have intentions of shutting down the forum next March although the website itself will most likely remain up indefinitely or until global financial collapse etc :)
Maybe inquire if this site will buy the information and make it an archive...hate to see good information go into the internet abyss
 

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^ Have you physically checked to see if the vacuum hose has been plugged or not? Did you or a previous owner perform the flapper mod on the bike?

FWIW, while doing the flapper mod on my 1000rr, I remember reading that failing to plug the vacuum hose (to throttle bodies) would indeed set off a code and/or cause the engine to not run properly.

I imagine the two Honda flapper systems (RC51 and 1000rr) would be fairly similar in design and if left unplugged, would also cause a code to appear on the RC - but don't quote me on that.

Hopefully someone else can confirm that for you...
 

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I did the mod almost a year ago and cant remember if I plugged it or not. Ive been under it quite a few times and cant find a hose thats just hanging out by its self. Ive got a 10 code right now and have replaced both baro sensors and its still there. I figured it had something to do with the line for the flapper. There were no codes before that.
 

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Well I found the hose that connected the flapper assembly to the manifold. Glued a screw into it for a good seal. The FI light still flashes the 10 code. Does anyone have two good baro sensors i can borrow for testing? Id hate to buy new ones and not fix the issue. Sorry for the thread jack. I can move this if need be.
 
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