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Discussion Starter #1
So I have a 2016 GSXR 1000 a guy brought in and it keeps hitting this early red line at 12k RPM's only when the throttle is at 100%.

If you hold the throttle at 95% or less lets say, it clears right past the 12k limit and goes all the way to the 14k red line with no issues. It only happens when your 100% maxed out on the throttle and yes it does it in each gear only on the street. I've only got to test this in 1-5 gears at 12k rpms because 6th on the street is too fast lol. Other than that the bike rides perfectly fine no issues. There are no check engine lights.

The bike is bone stock ATM so no PC or flashed ECU or quick shifter to get into the way. These are some of the thing I have checked/fixed to try to get this issue to go away. Swapped the ECU from another bike to see if that would change anything. The kickstand switch is no longer on the bike so the circuit is soldered together. No kinks in the fuel line. Replaced the fuel pump with a Schnitz pump and new filter. Basically sure its not a fuel issue. Checked the TPS sensor and it reads the -C00 so I asume that's correct also.

At a dead end on what else it could be. The only thing I can think of that wont throw a code and ride perfectly fine is maybe the cam position sensor but to be honest I'm not too knowledgeable on that. I'm pretty sure the crank position sensor would throw a code and the bike wont start. Also even if one of these sensors were to mess up while riding the bike shouldn't it throw a code or at least flash or so showing is wrong? Any help is appreciated.
 

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No, you're not sure it's not a fuel issue. If you didn't do a fuel flow code, you have no idea what your fuel system is doing.
 

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No, you're not sure it's not a fuel issue. If you didn't do a fuel flow code, you have no idea what your fuel system is doing.
Fuel flow code?? By just testing the fuel pump and regulator with a flow/pressure gauge because yeah I did that and its good.

The bike does not fall flat when reaching the limit, its pulling hard and then instantly it feels like its a ignition cut type of deal.
 

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Early redline would imply that the motor behaves like it bounces off the limiter at 12K, but I assume you mean it tops out and stops accelerating past that. Just_Nick probably meant fuel flow test/check, but in any case note that if you just measured pressure with the engine off, or idling, and found it within spec, that doesn't say much more than that you don't have any leaks in the fuel system. If you haven't done so already, you should measure flow, as described in the service manual.

If that checks out, keep in mind that there could still be blockages at the injectors, which the test wouldn't detect. Apart from that, and speaking from experience, such a top-end power delivery issue, without any apparent problems at lower loads, could come about due to worn spark plugs.
 

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Fuel flow code?? By just testing the fuel pump and regulator with a flow/pressure gauge because yeah I did that and its good.

The bike does not fall flat when reaching the limit, its pulling hard and then instantly it feels like its a ignition cut type of deal.
It's not a pressure-based test, it's volume based. The fuel flow test (not code) measures the volume the pump outputs in a certain time, because a pump that's restricted can feel like ignition cutting. Also, the falloff is not going to be linear unless it's only a minor restriction. Which also explains the ability to reach 14,000 RPM when you're not demanding the same amount of fuel.

The test is in the manual.
 

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Discussion Starter #6
Early redline would imply that the motor behaves like it bounces off the limiter at 12K, but I assume you mean it tops out and stops accelerating past that. Just_Nick probably meant fuel flow test/check, but in any case note that if you just measured pressure with the engine off, or idling, and found it within spec, that doesn't say much more than that you don't have any leaks in the fuel system. If you haven't done so already, you should measure flow, as described in the service manual.

If that checks out, keep in mind that there could still be blockages at the injectors, which the test wouldn't detect. Apart from that, and speaking from experience, such a top-end power delivery issue, without any apparent problems at lower loads, could come about due to worn spark plugs.
Yes that is exactly what it is doing bouncing off the limiter at 12K. I do not mean it tops out and stops accelerating past that. If I part throttle it to the 14K redline it behaves identically as the redline I see at 12K at WOT.

Is there a PDF link to the service manual? Is the test were you just measure to see if the bike flows xxxx ml in 30 seconds or it meets the required fuel pressure? I was thinking of taking the injectors in to get clean/flow tested but I figured with only 5k miles could they be dirty already? Yes spark plugs were already changed with a brand new set. Did not change anything.
 

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Yes that is exactly what it is doing bouncing off the limiter at 12K. I do not mean it tops out and stops accelerating past that. If I part throttle it to the 14K redline it behaves identically as the redline I see at 12K at WOT.

Is there a PDF link to the service manual? Is the test were you just measure to see if the bike flows xxxx ml in 30 seconds or it meets the required fuel pressure? I was thinking of taking the injectors in to get clean/flow tested but I figured with only 5k miles could they be dirty already? Yes spark plugs were already changed with a brand new set. Did not change anything.
The newer bikes have a longer test, not a 30 second test. And it's not an or requirement: you need to check both flow and pressure. Don't touch fuel injectors until you've verified that the fuel system is okay and your exhaust valve isn't having issues not fully opening, too.
 

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If you hold the throttle at 95% or less lets say, it clears right past the 12k limit and goes all the way to the 14k red line with no issues. It only happens when your 100% maxed out on the throttle and yes it does it in each gear only on the street.
Yes that is exactly what it is doing bouncing off the limiter at 12K. I do not mean it tops out and stops accelerating past that. If I part throttle it to the 14K redline it behaves identically as the redline I see at 12K at WOT.
This is not what I expected and, together with your quote above, about making to to redline at 95% throttle, makes a fueling issue a less likely explanation. Assuming you're not exaggerating too much about the 95% figure above, it would have to be a very delicate restriction indeed to cause noticeable problem during the last 5-10% of throttle travel only as the fueling demands of the engine don't change too much at that stage. It would also most likely lean out and stop accelerating, instead of bouncing as if rev-limited.

Don't misunderstand me though, you should perform a flow test at least (a pressure test would be interesting too, but only if you can get a reading at higher loads, which would be dangerous to say the least, unless you have a logging setup available). It is still not unlikely that it is down to fuel, and you should get the easier tests out of the way first, to rule out as many possibilities as possible.

Checked the TPS sensor and it reads the -C00 so I asume that's correct also.
The TPS sensor, being immediately related to throttle travel is getting a more likely suspect. After the fueling tests, I would suggest that you:

a) make sure that you get "-C00" with the engine running and warmed up, because if you get it with the engine stopped, your TPS is likely set too low.

b) disconnect the TPS sensor coupler and probe the middle (P/B) and one of the outer leads (say the B/Br) with a DMM, set to resistance measurement mode. Some needles and alligator clips may come in handy. Slowly turn the throttle and look at the reading. You should make sure that you see no erratic jumps or, more importantly, any suspicious discontinuities (i.e. jumps) in reading (especially during the last 5% of travel).

Is there a PDF link to the service manual? Is the test were you just measure to see if the bike flows xxxx ml in 30 seconds or it meets the required fuel pressure? I was thinking of taking the injectors in to get clean/flow tested but I figured with only 5k miles could they be dirty already?
You'll have to search around the web for a manual. I agree with Just_Nick that you should postpone testing and cleaning the injectors (as it is a more "invasive" test) until after you've ruled out the more likely and less invasive to test eventualities.
 

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Discussion Starter #9
The newer bikes have a longer test, not a 30 second test. And it's not an or requirement: you need to check both flow and pressure. Don't touch fuel injectors until you've verified that the fuel system is okay and your exhaust valve isn't having issues not fully opening, too.
Okay I've been trolling the internet for this PDF service manual for a 2016 gsxr 1000 with not much luck at all :( Exhaust valve is disconnected, I checked into that also before.
 

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This is not what I expected and, together with your quote above, about making to to redline at 95% throttle, makes a fueling issue a less likely explanation. Assuming you're not exaggerating too much about the 95% figure above, it would have to be a very delicate restriction indeed to cause noticeable problem during the last 5-10% of throttle travel only as the fueling demands of the engine don't change too much at that stage. It would also most likely lean out and stop accelerating, instead of bouncing as if rev-limited.

Don't misunderstand me though, you should perform a flow test at least (a pressure test would be interesting too, but only if you can get a reading at higher loads, which would be dangerous to say the least, unless you have a logging setup available). It is still not unlikely that it is down to fuel, and you should get the easier tests out of the way first, to rule out as many possibilities as possible.

The TPS sensor, being immediately related to throttle travel is getting a more likely suspect. After the fueling tests, I would suggest that you:

a) make sure that you get "-C00" with the engine running and warmed up, because if you get it with the engine stopped, your TPS is likely set too low.

b) disconnect the TPS sensor coupler and probe the middle (P/B) and one of the outer leads (say the B/Br) with a DMM, set to resistance measurement mode. Some needles and alligator clips may come in handy. Slowly turn the throttle and look at the reading. You should make sure that you see no erratic jumps or, more importantly, any suspicious discontinuities (i.e. jumps) in reading (especially during the last 5% of travel).

You'll have to search around the web for a manual. I agree with Just_Nick that you should postpone testing and cleaning the injectors (as it is a more "invasive" test) until after you've ruled out the more likely and less invasive to test eventualities.
Yes I'm trying to perform this fuel test if I can find the PDF manual online but no luck so far. I only keep seeing the quicker fuel test not some long drawn out process.

To be honest I feel like it is the TPS sensor but I just didn't want to go out and jump down that route if it was okay. I will check the TPS when the bike is running and hot I think I did check it when the engine was stopped but I don't remember.

I did not check this with a meter but I have calibrated other TPS this way so I know how to check it. I can check that out in the last 5% because thats seems like the issue.

I have access to a PC5 for the bike. I wonder if there is a logging function in there I could pull up to record a pull. At this point I'm thinking of taking it to a dyno where I can open up the computer and see whats going on. I'm used to cars where I just plug up the laptop and datalog a pull but on the bike I cant hold the laptop and do some pulls.
 

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I can't locate a manual right now, but the contents in this link seem to be ripped from the manual (although it doesn't state the model clearly, as far as I could tell, but from the photos it seems to be the last pre-L7 model). If anything it seems to specify a shorter test, but in any case I wouldn't expect the numbers to differ much anyway. The engines of relatively recent models (with the exception of the last) are not that different in terms of power, so their average fuel requirements should be similar.

As an example, the service manuals for the K6/7 750, K8 750 and L1 600 I have at hand, all specify 167-168ml/10sec[*]. A manual fro the older 2000-2002 750 model specifies 1200ml/30sec, but I can only assume that's a misprint as it's substantially higher than anything else I've seen.

[*] The specifications probably add a generous margin to the maximum requirement figure for the engine. It is also likely that parts, such as the fuel pump assembly, are shared between the various models, which might explain the common specification for the 600/750 models.
 

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I know the newer ones have a 30 second test. Just don't remember the volume.
 

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Discussion Starter #13
I know the newer ones have a 30 second test. Just don't remember the volume.
Okay well at this point I have given up because this manual is impossible to find and everyone keeps saying "fuel test" but no one knows what to exactly do. Dropped the bike off at the dealership and they said they have the items to test fuel flow and fuel pressure. Both came back good and they said everything checks out 100% fine. I didn't ask them to look at anything else because I wasn't paying extra for that. They said with no codes the bike isn't going to tell anything else.

So at this point we can 100% eliminate fuel pump. It either is something electrical keeping it from reving like a sensor, tps, or maybe injectors.
 

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Discussion Starter #14
Problem fixed for anyone wondering.... Crank sensor and cam sensor were giving weak signals at 12k causing ignition cut. This did not throw a code like normal because the sensor still worked it just was tossing a weak signal saying things were a little off and to kill power.
 
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