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Discussion Starter · #1 ·
Hello Streetfighter fans! I have a 03 636 streetfighter and I am having an issue with it not being able to pass 5k+ rpm and 55mph. I stutters if I try to push it past 5k like I'm hitting a rev limiter. So what I am doing is checking sensors, ignition and fuel pump to make sure nothing is bad. But I do have one concern interms of how the intake box is setup for you guys that have the same bike. I've heard not getting enough air in bc of how it's setup can cause this type of issue. The way I did mine is I cut the bottom of the "bowl" to allow air in. I've seen other setup like doing "Ram Air Mod" (I don't have RAM Air). On the 03 models, is there any specific way of setting up the intake box to allow enough pressure to come in? Thanks in advance.
 

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Mine was fuel pump was gunky. Bike was fine riding slow in all gears but on the track, it wouldn't Rev and was super slug and slow. Took the fuel pump out, tore it apart and cleaned everything, filter and all with contact cleaner, put it all in and got to ride the next session.
 

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Second on the fuel pump. My 03 Z1000 developed a similar problem. Initially it would only bog/cut out if you really laid on the throttle for a bit, but got worse (quickly) to the point a steady cruise at 60 was about all it could do. I replaced the fuel pump with a HighFlow Systems one off ebay, they're like $60 or something. Problem solved. Apparently this was a pretty common issue on EFI kawi's in 2003/4, there's an updated part # now though Kawi will only sell you the entire pump assembly (not just the motor cartridge) for like $650.

That replacement pump shit the bed like 2 years later, I messaged them and they sent me another one no questions asked. That one was still going fine when I sold it.
 

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Discussion Starter · #5 ·
Yeah the 03's are EFI.

Good feedback guys thanks. I agree with all 3 of you with pressure loss and fuel issues. I will be taking her apart this weekend and work on the problem. I have been riding around for the past few days before I go in and search for the problem. I can cruise, not wringing on the throttle much and could go through the RPM smoothly until like 60mph around 6k RPM and she should just start bogging. I do feel it's either a pressure loss but I am leaning more on the fuel side. I feel like around that RPM, it's not being fed enough fuel but I might be wrong. I am just going to spend the extra money to replace the fuel pump, spark plugs and spend time working on the intake bowl and try to get some more air through the intake box. I will come back and post the results.
 

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had a similar problem on the wifes 07 ZX6, guy we bought it from had it "sitting a bit" and would start it up every so often. but this is what we found in the tank/pump/filter.









took that sucker apart, let it soak in seafoam and cleaned it up real good. no more problems.
 

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Discussion Starter · #9 ·
Wow you had junk inside your fuel pump. I replace the entire fuel pump. When I connecting a 12v batt. to the old one, the prime was so much lower than the new one. Thought it was going to be my fuel pump that limited my rev but I did a DIAG for Fi code and it showed up as 1) #13 air temp sensor 2) #32 for sub throttle body malfunction. Im going to have to replace those two sensor and see where we go from there.
 

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Make sure the air temp sensor is actually connected. People forget to plug them back in a lot after removing the airbox.

The subthrottles are also kind of optional on these bikes. They're to smooth out the throttle response, disconnecting them in the full open position is a somewhat popular "mod", it makes the throttle sharper and snappier especially at higher rpm. I think it hurts driveability, but a lot of people like it. At least on my Z, you could disconnect the servo. It would turn the FI light on, but the bike still ran 100%.

I'm fairly sure these bikes do not have a "limp mode", as in reducing power to a pre-set level when there's a malfunction. The ECU falls back on a default value when one of the sensors fails which likely isn't optimal so power may be hurt a little, but it should still run more or less OK.
 
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