'00 SP1 'flat spot' - Honda RC51 Forum : RC51 Motorcycle Forums
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post #1 of 11 (permalink) Old 05-29-2014, 10:30 PM Thread Starter
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'00 SP1 'flat spot'

just picked it up. previous owner said it has a 'flat spot' or hesitation around 5000. he also said he put it on a gas analyzer & it was lean around there, hence the sputter.
after a couple rides myself it seems to be more between 6000-6500.
i just installed a Dobeck Techlusion TFI unit & set it to the recommended settings as well as played with it a little & it only got worse, not better. it crisped up my throttle response but there is still that hesitation between 6000-6500.
bike has K&N air filters & a full Jardine system on it (2 into 1).
before i start ripping into it what would a seasoned RC51 owner/rider suggest?
i dont have cash to throw at it wildly & will most likely be doing all the work myself. i was going to start simple with tank fuel filter & go from there. once the tank is off i can check air filters & look for any vacuum leaks, loose wires, etc. it pulls as hard as hell from 7000-redline & rides as smooth as any 1000cc V-twin superbike could from idle to roughly 6000.
i'm frustrated & wont go back to the previous owner.....i still think i got a good deal at $3000.

suggestions will be much appreciated

thanks!

paulie
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post #2 of 11 (permalink) Old 05-29-2014, 10:32 PM
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Go to rc51.org and read up on the flapper valve mod.

2001 SP1 (sold)
2004 SP2 (properly stored)
2012 Ruckus (stolen)
2015 Grom (under construction)

Weyrauch pronounced (Y Rock)...Rock for short.

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post #3 of 11 (permalink) Old 05-29-2014, 11:15 PM Thread Starter
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Thank dog!

Quote:
Originally Posted by weyrauchrc51 View Post
Go to rc51.org and read up on the flapper valve mod.
You sir are the best! The problems related to the flapper valve described in that thread are excatly what i am experiencing. I will be ripping into my ride tomorrow! I'll update the thread once its done.

Thanks!!!!
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post #4 of 11 (permalink) Old 05-30-2014, 12:05 AM Thread Starter
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wtf......dont have a flapper valve

flapper valve assembly has already been completely removed from my bike. there is a nice rubber plug (from a Brembo brake master) that would almost pass as factory if i didnt already see diagrams of where the vacuum line is supposed to connect to the flapper valve.

DAMN.......back to square 1

Last edited by bcpaulie; 05-30-2014 at 12:32 AM. Reason: added pic
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post #5 of 11 (permalink) Old 05-30-2014, 08:37 AM
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The Rogue exhaust information page: '2-1 exhaust fad' could be the answer.
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post #6 of 11 (permalink) Old 05-30-2014, 09:05 AM Thread Starter
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?

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Originally Posted by theavidmoto View Post
The Rogue exhaust information page: '2-1 exhaust fad' could be the answer.
read the entire article & checked out the dynos. although it is obvious there is a dip in power, i cant see it making the bike hesitate like it does. its almost as if there is a short or it isnt getting fuel at the 6000-7000rpm range.
there has to be a culprit......just need to find it.

would having the bike dynoed 'show me' whats wrong or just show me that there is a significant 'hole' in power at that rpm range?

can the RC be hooked up to scope?
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post #7 of 11 (permalink) Old 05-30-2014, 11:46 AM
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What you need is to have the bike mapped on a dyno.
When I first bought my RC51, the prior owner had also installed a Jardine 2-1 exhaust.
However, while it had a PCIIIr installed, I doubt he ever had it dyno'd as it had such a lean spot at 5800 RPM, that it would start misfiring from being so lean.

All I did was have it dyno'd and the lean spot disappeared and the bike ran perfect up to where I replaced it with an Akrapovic full system, which I also had dyno'd with the same results.
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post #8 of 11 (permalink) Old 05-30-2014, 06:08 PM Thread Starter
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Spent the tearing the beast down. Did the PAIRS mod, cleaned the throttle bodies & put it all back together. NO DIFFERENCE.....except the FI lite comes off & on now. Maybe because i disconnected the high pressure fuel line???? Still has a bad hesitation between 6000-7000rpm. Talked with a local dyno tech & he said to spend the money on a PCIII & download the Jardine map. Great, except i just blew all my spare cash on the Dobeck. Gonna ride it & play the waiting game until my allowance allows for a PCIII.
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post #9 of 11 (permalink) Old 05-30-2014, 06:20 PM
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What code is the FI light giving you? If it's one long blink (1.3seconds) that is a 10. Baro sensor. That's the one you might have unplugged at the top front of the snorkel. Plug it back in and should make a code 10 go away.
Eventually, you should erase the stored codes from the ECM's memory.

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post #10 of 11 (permalink) Old 05-30-2014, 09:20 PM
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Sell the K&N filters on Speedzilla and buy some OEMs would be an excellent start. Sub put you on the right track with a custom dyno....it is th eony true way to fix your hesitation properly if at all with a 2-1 System



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