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Discussion Starter · #1 ·
I've been looking around for a fix almost everywhere. My bike sometimes lets me fully rev while in neutral, but sometimes not even past 11k.

When I ride with gears, it usually wont rev past 6-8k rpm and bogs down. Feels like it doesnt get enough fuel? I also installed SP Quickshifter + Launch Control kitbon this bike.
The bike hadn't this kind of issue before I tore it down before winter. I unplugged almost all the wirings and exhausts etc.
My previous post is below in there as name Coolant leak + white smoke. It had a minor coolant leak from the cooler and got fixed it by now.

However I have done the following in order to eliminate this issue:
  • Disassemble the launch control kit
  • Changed back the old different kind of air filter than the new one
  • Borrowed a fuel pump whichs fuel filter was cleaned
  • Checked ignition coils, looks fine
  • 2 fuel injectors were broke, replaced them
  • It also had and has C28 error due to me disassembling the 2nd throttle body (huge mistake). Took the butterfly plates off. C28 is still in there but ordered STV Eliminator kit
  • Spark plugs seemed to be fine. A mechanic said it sounds normal and it does
  • Checked for air leaks, didnt seem to find any

Any ideas?

Thanks in advance!
 

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Discussion Starter · #3 · (Edited)
Bogging down is most often a fuel pump filter issue. Check the flow rate per the service manual procedure.
I tested the bike with a fuel pump that had a filter which was cleaned. I even saw that filter by myself and that repair shop borrowed me that one, didn't fix with it.

I've been thinking about if the problem exists in the ECU? It has been flashed and I notice that when I release the throttle, it "decelerates" more aggressively than before. At least that's how it feels like.
When riding to turns and releasing the throttle, it feels really scary because the throttle won't respond quickly enough.

But yeah, I should check out the flow rate from the manual.

EDIT: However the mechanic who took care of this bike before, said that the gas tank had full of moisture. But it was strange that with another fuel pump it didn't start to work. So could the problem lay elsewhere? The fuel injectors were fine and checked.

Don't really know if it "bogs down" but kinda being like a limiter.


I had full throttle in the video.
 

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"I even saw that filter by myself"
That sounds like you saw the strainer, not the filter. It's difficult to see any part of the main filter element.

The ultimate test is to measure the fuel pressure while you're riding & bogging. But that takes a bunch of hooking things up. The flow test is much easier and is usually definitive. Fuel injector cleaner will remove injector deposits but it will take several tankfuls of gas to see results.

The second most common cause of bogging/rev limiting is a problem with the secondary throttle system, either they aren't opening fully or the secondary injectors aren't working or are clogged. Your video sounds more like that. You can watch the injectors cycle when you turn the ignition on. It's also possible to swap the primary and secondary injectors but the screws that mount the fuel rail have a habit of sticking in the throttle body. But I don't know why the secondaries would clog and not the primaries, so bad electrical connections would be more likely. However electrical issues should cause a fault code. You said that you have C28. I can see the red fault light and, barely, FI being displayed in the video. You have to get rid of that. You're operating in fail-safe mode.
 

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Discussion Starter · #6 ·
"I even saw that filter by myself"
That sounds like you saw the strainer, not the filter. It's difficult to see any part of the main filter element.

The ultimate test is to measure the fuel pressure while you're riding & bogging. But that takes a bunch of hooking things up. The flow test is much easier and is usually definitive. Fuel injector cleaner will remove injector deposits but it will take several tankfuls of gas to see results.

The second most common cause of bogging/rev limiting is a problem with the secondary throttle system, either they aren't opening fully or the secondary injectors aren't working or are clogged. Your video sounds more like that. You can watch the injectors cycle when you turn the ignition on. It's also possible to swap the primary and secondary injectors but the screws that mount the fuel rail have a habit of sticking in the throttle body. But I don't know why the secondaries would clog and not the primaries, so bad electrical connections would be more likely. However electrical issues should cause a fault code. You said that you have C28. I can see the red fault light and, barely, FI being displayed in the video. You have to get rid of that. You're operating in fail-safe mode.
Could be the strainer, he removed the bottom of it and I saw a thing that looked like a coffee filter 😅
About my secondary throttle system, do you mean the butterfly plates ain't opening? Because I removed them already.

I'm not even sure how to do the fuel flow test after checking from the manual.

But if the C28 causes me to get the fail-safe mode, then wouldn't it be able to rev to 11k to 15k rpm in neutral?
I am getting rid of it as soon as the eliminator box arrives, that eliminates the C28 fault code. Healtech also stated this: "Note: After installation, we recommend having the AFR (air-fuel ratio) of the engine checked by a dyno center and adjust if necessary."

So this should be done as well?

 

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The service manual is vague on exactly what happens, saying only "FI system is provided with fail-safe function to allow the engine to start and the motorcycle to run in a minimum performance necessary even under malfunction condition." and "But, the engine running condition is not complete, providing only emergency help (by fail-safe circuit)." That could easily mean a lower rev limit.

Unless you removed the secondary throttle shaft, you should be able to see it turning. I think it goes through a procedure on startup to determine the limits of travel. No butterflies probably screws that up.

The filter is on the top, not the bottom.
 

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Discussion Starter · #8 ·
The service manual is vague on exactly what happens, saying only "FI system is provided with fail-safe function to allow the engine to start and the motorcycle to run in a minimum performance necessary even under malfunction condition." and "But, the engine running condition is not complete, providing only emergency help (by fail-safe circuit)." That could easily mean a lower rev limit.

Unless you removed the secondary throttle shaft, you should be able to see it turning. I think it goes through a procedure on startup to determine the limits of travel. No butterflies probably screws that up.

The filter is on the top, not the bottom.
That could explain it, because it really feels more like of a rev limiter.
I didn't remove the shaft but only the butterflies. Before that, the butterflies only shook around (trying to open, but they couldn't?). Then when I put the wrong wirings in the actuator, it moved them a little bit but not completely. And this was really the incorrect cables for it, but it fit since I just have enough length to connect them.

I'll update this once I have the eliminator and if the problem still exists after that.
 

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I'm unfamiliar with the Healtech. The C28 will automatically go away if faults in the secondary throttle are corrected. So I don't see why that shouldn't also happen with the Healtech. Does it connect to both secondary connectors?
 

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Discussion Starter · #14 ·
How about in the wiring to them? Early on here you said that you were fiddling with it.
I actually know the reason. My local vendor sold me the STVE-01 version which is incompatible with my bike, it should be the STVE-10 version. They had the incorrect eliminator up for sale stating that it fits my 07 GSX-R. Have to order the correct one and return the incorrect one and wait for another 3 weeks. :rolleyes:
 
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