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Discussion Starter #1
I have replaced the fuel pump. Thinking the bike wasn’t getting fuel. It starts with starting fluid. After the fuel pump replacement it still seems to not get fuel. How should I proceed. It’s a 2002 yzf r1. I bought it as a wreaked bike. It did not run when I bought it
 

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Make sure fuel line from the fuel tank is not kinked. Common problem for Yamaha motorcycles.
 

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Run the bike briefly with no airbox to see if the injectors are firing. If the issue is fuel you can start the bike with the air box removed from the throttle bodies to see if there's fuel spraying. Once you verify that's there some fuel reaching the intake, you can move forward from there.

On the older bikes without an ECU controlled sub throttle (2002 R1), there's an idle air control valve that meters the air/fuel ratio start up. When turning the key on the ECU will be reading atmospheric pressure using the intake manifold pressure sensor to determine injector duration. During warm up the ECU will be reading the temperature of the coolant. If you think the issue is the amount of fuel that is being calculated, check the Intake pressure sensor and the coolant temp sensor with a multi-meter.

If you believe the issue to be the amount of fuel being supplied to the injectors, the older bikes often use an open loop fuel pressure regulator between the injectors and fuel pump. A fuel pressure test after the pressure regulator will give you a definite answer.

There's a couple other AFR related issues it could be but I would start there for testing. Always the possibility of tight valve lash, leading to more air and thus a lean AFR on start.

I go to MMI so if we can't figure it out, I may be able to pick the brains of others around here or instructors with 30+ years of experience.
 

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Discussion Starter #4
Run the bike briefly with no airbox to see if the injectors are firing. If the issue is fuel you can start the bike with the air box removed from the throttle bodies to see if there's fuel spraying. Once you verify that's there some fuel reaching the intake, you can move forward from there.

On the older bikes without an ECU controlled sub throttle (2002 R1), there's an idle air control valve that meters the air/fuel ratio start up. When turning the key on the ECU will be reading atmospheric pressure using the intake manifold pressure sensor to determine injector duration. During warm up the ECU will be reading the temperature of the coolant. If you think the issue is the amount of fuel that is being calculated, check the Intake pressure sensor and the coolant temp sensor with a multi-meter.

If you believe the issue to be the amount of fuel being supplied to the injectors, the older bikes often use an open loop fuel pressure regulator between the injectors and fuel pump. A fuel pressure test after the pressure regulator will give you a definite answer.

There's a couple other AFR related issues it could be but I would start there for testing. Always the possibility of tight valve lash, leading to more air and thus a lean AFR on start.

I go to MMI so if we can't figure it out, I may be able to pick the brains of others around here or instructors with 30+ years of experience.
I replaced the entire throttle body assembly injectors and all. I am still having the same issue. I will start to do the list of thing you recommend. I will get back to you. Thank you so much for your advice.
 

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I had a ton of issues with my fuel pump not sealing onto the o-ring correctly within the tank... its a poorly made housing in my oppinion. I was losing alot of fuel pressure, I replaced the pump, went through the coils plugs and injectors, nothing... but it would always start right up on starting fluid. So maybe check that o-ring,... I instead of buying a new housing I just snugged it down to the housing with zipties lol...cranks in like 4 turn overs every time now.

Goodluck.
 
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