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Okay this is weird. I was easing onto the throttle today, and then I decided to pin the throttle open. The RPM's climbed steadily to 9k, and then stopped! It wouldn't go higher than 9k with the throttle pinned wide open.

Then I eased off maybe a quarter turn, and the RPMs slowly began to climb again. What is this? Normal? I hadn't noticed it before.

Maybe a fuel pump problem...
 

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Sounds like you're in need of a cable adjustment, idk. :confused1
 
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If you have a PC or Bazzaz, an issue with the map, or a fuel pump/fuel line issue.
 

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these forums were a lot nicer when an 18yr old kid wasn't giving sub-par advice in every thread.

Here's an idea: Look at the smaller picture before dropping money on an expensive part that may not be the issue.
 
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Here's an idea: Look at the smaller picture before dropping money on an expensive part that may not be the issue.
And what would the smaller picture be?

Fuel pump relay obviously works.
Secondary injectors are not the issue as they kick in at 4400-5000 RPM.
Main fuel injectors are not the issue, as even if they were clogged, the secondary injectors would still supply enough fuel to reach redline.
The air filter obviously isn't an issue, since it would not cause RPM's to peak at 9000RPM throughout different gears, as more air would be forced through at higher speeds.
Injector duration/operation wouldn't cause the bike to run fine then stall out at a specific RPM all the time. The odds of that happening are near impossible.

So, that leaves 3 possible causes.
1) A clog or pinch in the fuel line. However, again, for the bike to stall out at a specific RPM with no issues prior to that RPM, not likely.
2) Fuel pressure regulator is bad. Too bad this is a part of the fuel pump unit.
3) Fuel pump is bad.

Timing is advanced by the position of the TPS and CKP, and as there is no O2 sensor on US bikes (aside from CA models) to adjust the ST and LT fuel ratio (a DTC would be set and the MIL would flash if this was a CA bike with an O2 sensor as the LT fuel ratio would have to stay adjusted for too long of a period to correct the ST ratio). With a lower fuel pressure then what the engine needs, enough fuel will not make it's way into the combustion chamber to produce the power needed to continue to accelerate under a load. Incorrect fuel pressure will also stay constant, so that would give the engine a chance of reaching a peak RPM all the time.
Now what happens when the throttle is slightly closed, the ECU retards the ignition timing to accommodate the decrease in air flow. Since the ignition retards, that gives a better chance of complete combustion that produces power with the limited fuel supplied.

There is also the chance that both the TPS and CKP are bad and causing timing to advance too much, but then the knock sensor would detect detonation and would retard the ignition timing while setting a DTC and the MIL turning on.

If I missed anything, I apologise. I don't have a service manual for the 03-06 model to go off of. It really does come in handy at times to be certified by Honda in fuel and emissions system diagnosis/repair.

Edit: It could also be the ICM is damaged, which would mean the ECU needs to be replaced. If the bike will rev up to redline in neutral or with the clutch pulled in, this wont be the issue.
A faulty knock sensor would also cause a problem, but would set a DTC.
Incorrect valve timing (CMP sensor issue) or worn valve springs too could cause a similar issue, but that would just be overall poor performance and not the bike stalling out at 9000RPM. Again, a DTC would be set and the MIL would light.
A faulty speed sensor would cause a problem throughout the entire RPM range.

A stuck open PAIR control valve could be pumping too much exhaust gasses back into the airbox. I'm not sure if this could cause the engine to stall out at a certain RPM, but I highly doubt it.

I think that's everything covered. I hope that is in-depth enough for you and not "sub par". To be honest, what need is there really to explain everything that it could not be when I can just tell the OP what is wrong?
 

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Discussion Starter #18 (Edited)
If I missed anything, I apologise. I don't have a service manual for the 03-06 model to go off of. It really does come in handy at times to be certified by Honda in fuel and emissions system diagnosis/repair.
hahahahaha Pwned. Thanks for the reenforcement Demented. The fuel pump what my first guess anyways, just from a basic understanding of the bike.

EDIT: Would it be okay to rev it to 11 - 12k in Neutral just to check the ICM?
 
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hahahahaha Pwned. Thanks for the reenforcement Demented. The fuel pump what my first guess anyways, just from a basic understanding of the bike.
No prob. There's also some other threads in the troubleshooting section with the same 9000RPM issue, and all were solved by replacing the fuel pump just for more "proof".

Edit: No harm will come from revving it in neutral to check.
 

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Not that I would ever doubt the great Demented (who is probably spot-on BTW), but I've seen a similar issue caused by tank venting problems. The tank could "seep" enough air to idle and run but with time or fuel demand would hesitate.
 
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