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Join Date: Jan 2019
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2009 CBR 600 suddenly died, power to fuel pump yet no prime
Alright first of all let me say this forum is a wealth of knowledge. I have read the stickied thread, I have read pretty much every thread I could find on the forum concerning a fuel pump not priming. I wouldn't post unless I thought my situation was unique, and I also want to put this down in case anyone else runs into this problem.
I have a 2009 CBR 600 race bike that has 1.5 seasons on a pretty freshened up motor. Last year at the final round, during the second practice session coming out of a slow corner my bike started bogging down and loosing power until it completely died. Thinking I may have dropped a valve or something I pulled in the clutch and waited for the crash truck to come around at lunch time. Once I finally got my bike back, I tried to start it and it fired up like normal, sounded good but died within a few seconds like it wasn't getting fuel. I looked in my owners manual and tested the power source to the fuel pump. It was getting power for the first few seconds after turning the key on yet the pump wasn't priming. Manual says to replace the fuel pump. I can't find one in time for that race weekend so I park it and hang out.
I've went to the bike a few times over the winter and turned the key on yet the pump would never prime and of course my bike would just turn over and not start. Yesterday I finally got around to digging into it some more. I tested the power going to the fuel pump again and again it showed 12v for a few seconds after turning the key on. So then I hooked up a 12v battery directly to the fuel pump and nothing happens, seemingly confirming my fuel pump is bad. At this time I notice that the breather lines from the two tubes under the tank are not there. Not sure how long they have been gone as I've been riding this bike for a while with zero issues.
Now I figured might as well pull the fuel pump out and see if a wire inside is disconnected or something obvious is wrong with it. Once I pull it out, I see all the wires appear to be fine. I start pulling it apart, and first I test the continuity in the wires from the connector to the motor. It says there is continuity, weird I think. Motor must be shot. So I continue to pull it apart until I get the motor out. Figure why not just test the motor and see what happens. When I hook the motor of the fuel pump directly up to a 12v battery it immediately starts spinning! Really weird, so I hook up the connection that goes from the outside of the tank to the motor and test with a 12v battery. Still spins. I test the actual connector, it shows continuity. So I put the whole fuel pump back together and again test it with a 12v battery and the fuel pump motor spins like it should. Went ahead and hooked up the fuel pump to the connectors on my bike and turned the key. It primes the pump just like it should. When I put the fuel pump back into the tank and put fuel to it, my bike started right up just like it always has. It was about 10pm last night, but today when I get off work I'm going to run it some more and see what my bike does.
I dunno if there was a loose connection somewhere in there? Maybe the motor is failing and still will stop working at some point. Do those breather lines serve a major function that would off the sudden stop the bike from working as it should? Obviously they will be replaced, and I'm going to pick up a used fuel pump to have on hand just in case this one shits out on me in the future. Of all the reading I've done on this I haven't seen a pump that had power going to it, but wouldn't prime. Yet would prime out of the bike and hooked up to a 12v power source, and once again after putting back into the tank everything worked normal. The only other thing that happened was my fuel gauge flashed at me after restarting it telling me there is now an open connection inside the sensor that gives it a reading. Maybe I hooked it up wrong or pulled a wire out, I'm gonna pull that back apart tonight and look into it as well. Wanted to give as much info as I could and hopefully as I continue to diagnose this problem I will get a firm answer.