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Discussion Starter #1
Here's the deal, I was riding my 2003 RC home from school today, I went to take off from a stop light, gave her some gas only to notice that she virtually flat-lined at 6-6.5k rpms. I figured it was just the power commander map, given that I swapped the fuel tank the other night so it can get painted. So, I reloaded the map on her and went to start her up when I noticed that the normal whine you get from the fuel pump priming the fuel system was a screech. Also, I noted that she didn't throw an FI code at me, plus she started up fine. However, when she was running, the fuel pump still kinda screeched a little. Any ideas would be greatly appreciated.
 

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This is all obvious stuff, but...
I'm assuming you only switched tanks, not the pump/filter? Did you get a good look at your pump/filter when you switched tanks. How about the inside of the original tank and your donor tank. Also, a bad ground might act like that. Do you have any way to check your fuel pressure? I'd start with that.

Does anyone know if the pump is rebuildable? I saved my old one just in case. I seem to remember about $250 for a new pump. (Dealer price) Much cheaper on ebay for a RC51 used pump/filter. $150 -200. Hope you figure it out and it doesn't cost much. :eek:
 

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did you twist the lines on install? take it all back down to wher you had it and start over. could have disconnected a wire also
 

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Discussion Starter #5
I'll give it a shot. The temp tank is kinda banged up from when I got hit 7ish months ago. But, I'll be sure to inspect the fuel pump when I remove it. Also, I'll check all connections and what not. Unfortunately, i won't be able to do that until tomorrow, but as soon as I know, I'll let ya'll know. The thing that got me was the completely lack of an FI code, though.
 

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Discussion Starter #6 (Edited)
Also, if there's anything else that it could possibly be, if ya'll could tell me now so I can look at everything tomorrow when I have time to work on her, that'd be awesome. As it is now, I'm gonna be re-removing the tank and re-inspecting the tank, inspecting the pump, and checking all connections.

Thanks
 

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Discussion Starter #7
Also, i was wondering if there was anything wrong with connecting the fuel pump back up to the bike, after I removed it from the tank, so I could listen to it spin up once I turn the bike on.
 

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Discussion Starter #8
Alright, so I drained the fuel, and out of curiosity, turned her on to let her prime...the screech was gone. I took off the tank anyway. I wiped out the inside of the tank with a clean rag, I cleaned the entire pump. The piping on the pump shows no dents or kinks, neither the pump motor, nor the fuel filter show signs of damage. The electrical connections are good. So, I put the pump back in, remount the tank, put fresh fuel in the tank. At first the sound was gone. The sound, though, eventually came back, but not nearly as loud as it was. Any thoughts?
 

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Since it is DC motor, the brushes either have contamination in them or are wearing out...I believe that is your noise.
 

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Discussion Starter #10 (Edited)
Contamination or wearing out after only 14k miles?

Anyhow, after I reassembled her, I took her for a quick spin out on the road. The problem with her power flat-lining was still there. I couldn't accelerate past 6.5-7k rpms in first, second or third gear.
 

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Discussion Starter #11
So, I put in the new fuel pump(Thanks, Ben), problem solved. Rev issue gone and noise is gone. Thanks to everyone who helped me out on this. I was baffled.
 

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Did you happen to change the fuel filter?

Yeah, a DC motor can fail in what seems like a small amount of time if contaminated or over worked.

Your bike falling on its face at higher rpm is not consistent with fuel pump operation. The pump is should have a the same pressure at idle as it does at the higher RPMs. The rubber grommets between the throttle bodies and the intake ,are they in tact?

Also, pull the ECU plugs and check for corrosion. This is a long shot but an easy and quick check point. If you have any dielectric grease, take a cotton swab and put a light coat on the ECU pins.

Wow , was I asleep at the keyboard. I am glad your issue is resolved.

So, my statement about the pressure being a constant is not correct? Please help me understand??? If it was a pressure issue, it should have had a diificult time starting and staying lit. Is the pressure variable?

FLOW...all the pressure in the world will do you no good without flow....sorry I am a bit slow at times :)
 

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Discussion Starter #13
Yup, I think it may have been a combo fuel pump/fuel filter issue, but since they are all virtually one unit, and the pump was making a weird sound when it was going, i went ahead and replaced the whole thing. Problem solved, the dielectric grease thing, though, I'm going to do that, it's just good preventative maintenance.
 
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