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K7 gsxr 1000 power loss/stuttering around 5000 rpm

+1 about the Bazzaz PDF instructions

vano said:
I believe it's stock ECU but I might be wrong too. I'll check on the weekend. What numbers would tell me that it's a Kit ECU rather than stock?
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theres prob a sticker on the ECU w/ a serial-number or two. it shouldn't be too hard to find out on Google if its a stock or Kit ECU.
 
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dowlinginchico said:
Lots of info here, and I may have missed it, but don't forget that some motos protect themselves. The ECU may be shunting power because it does not like what a random sensor is telling it. The fact it happens at the SAME exact RPM is an interesting bit of info.

Like others have said, get it as stock as possible and start testing. My first question would be is it the ECU+sensors, or is it something mechanical, but definitely get the add on stuff out of the mix.

I wish you luck, keep us posted
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+1 The consistency of the issue sounds electrical and not mechanical. As most have already said, definitely start with the aftermarket electronics.

I would then try to borrow another ECU and test that. Better yet, put your ECU on someone else's bike to prevent causing damage to the loaner ECU in case it's something on your bike causing a short.
 
I'll throw in one last thing. These issues turn out to be, time after time, so insanely simple thing, like a pin connector not firmly seated, a bad relay, and so on. It's crucial to work your way from one end of the bike to the other, and that includes the stop start switch, looking for bad connections.
 
Is it a cable or hydraulic clutch? I have seen it mentioned on hydraulic clutches that people have re-bled the clutch to get a small air bubble out of the system that caused an issue. Most mentioned they didn't need to replace the sensor, and one did take theirs to the dealer to have the computer recalibrated. I don't know if any of that would consistently occur at 5,000 rpm.
 
motorider365 said:
Is it a cable or hydraulic clutch? I have seen it mentioned on hydraulic clutches that people have re-bled the clutch to get a small air bubble out of the system that caused an issue. Most mentioned they didn't need to replace the sensor, and one did take theirs to the dealer to have the computer recalibrated. I don't know if any of that would consistently occur at 5,000 rpm.
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There is no sensor on the GSXR1000 hydraulic clutch. It's just a hydraulic clutch with a mini switch that lets the ECU know if the lever is pulled in.
 
I had a similar problem with cutting out at a specific rpm when warmed up. It was a split tube within the fuel pump assy. between two parts.

Putting a fuel pressure gauge on while riding could trouble shoot it. I have a spare fuel pump for an ‘05 that you can borrow to test.

I would first check all the electrical sources first.
 
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As it turns out I had the exact same problem today after having removed the gas tank and putting it back on. The bike ran great up till 4K rpm and whether I rolled on had or slow it dropped revs or died. I raised the tank and propped it up and it worked.

The fuel line was getting bent or pinched. I had taken the tank off a few times and raised the tank many times and never had that occur. So raise the tank check it and be careful about the fuel line and breather lines.
 
I had to pause further troubleshooting of the issue for over a year and finally got some time to look into it again.

I don't believe I have an issue with the gas line but it's possible that the pump could be faulty. I tested it out with a gas tank propped and ensuring that neither gas line nor breather line is bent.

I discovered that the power is cut off at different RPMs depending on what gear is on. On 1st gear, it cuts power at ~5k, on 2nd ~4.5k, on 3rd ~4k, on 4th ~3.5k. To me, it seems like the ECU tries to limit the speed.
I doubt it has anything to do with the speed sensor as I never had it connected to get the speed reading.

Since the issue is similar to how bike may behave when one of the Throttle Position sensors is faulty, I remeasured the voltage of both TP and STP sensors. Both sensors passed continuity check b/w sensor's coupler and the terminal sockets. Both output voltages within the spec range. Though, one observation was puzzling to me. Both sensors give 0L output when the output voltage reaches 2.0v. It's a very short drop at precisely 2.0v and then the voltage reading returns back once it passes 2.0v. At first, I observed it on the TP sensor and thought I found the culprit but then I got the same behavior with the STP sensor. While it's possible both sensors could be faulty, I find it unlikely. Also, I replaced the STP sensor when I initially started troubleshooting this issue.
Here's is an example of multimeter reading in slo-mo.

Wondering what other sensors might produce such behavior?
I thought of crankshaft sensor but that one tells ECU when to fire the spark and so far can't connect it to the power cut off. Besides, if the sparks were misfiring, the bike would sound differently with potentially small explosions due to either late or early firing.
 
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Have you tried removing the Bazzaz system yet?
 
I tried removing Bazzaz unit and ran the bike with the kit harness, but no Bazzaz connected. The issue persists. Since I've got 2 kit harnesses, I tested them both with no luck.
I'd like to make sure I've exhausted my options before I go down the route of buying a new stock harness and a new ECU unit.
 
There is an internal fuel filter in the pump in addition to the outside one. It is hell expensive, and the usual cure is to remove the pump and back flush the filter from the out put back to the input. Your symptoms sound like that. Also the other suggestion about running a fuel pressure gauge while riding would help confirm that.
 
I had the same symptom on an Aprilia and it turned out the internal fuel line in the tank would split under high pressure. AF1 has a kit for that. If you do check the internal filter, be sure to check the internal lines. I have a spare fuel pump for an ,05 if you want to try it and it fits.

Another option is to just swap tanks for a couple hours.
 
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