CBR 600F3 1995 - 1998 CBR 600F3 Forum

No fuel?

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Old Feb 1, 2023 | 09:06 AM
  #1  
Dutchnoskillz's Avatar
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Default No fuel?

Since I have my bike it always had starting issues (1 year) However it did start after long cranking. Recently my stator, rectifier and battery died before winter. I fixed it drove once and stored it for 3 months. Trying to crank it and wont start, I can see there is no fuel going to the carbs because the transparant fuel filter seems empty. I remember like 8 months ago the bike didnt start, gave a few taps on the fuel cut relay and it started instantly. (Cf318)
I removed the CF318 and jumped the blueblack and blue white wire and i hear the fuel pump clicking. If i put the fuel on Off the clicking goes slowly away but still no fuel. What is going wrong?
 
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Old Feb 1, 2023 | 09:43 AM
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If relay is running pump, but no petrol shows up:

1. is petrol leaving tank? petcock flows?
2. hose between tank pump not clogged?
3. hose before & after filtre not clogged?

Basically disconnect fuel hose at each junction and verify you have petrol flowing.
 
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Old Feb 1, 2023 | 08:37 PM
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Originally Posted by dannoxyz
If relay is running pump, but no petrol shows up:

1. is petrol leaving tank? petcock flows?
2. hose between tank pump not clogged?
3. hose before & after filtre not clogged?

Basically disconnect fuel hose at each junction and verify you have petrol flowing.
Thanks for your comment! will check soon, driving season hasn't started yet and no time/bad weather. I will start checking if the fuel does flow from begin till end.

What I wonder is when i jump the wires i hear the pump clicking but when trying to start i hear no clicking.
 
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Old Feb 2, 2023 | 12:31 AM
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Fuel pump isn't run by relay unless engine is spinning. Relay is pulsed by ignition-triggers from ICM to #2-3 ignition coil. This is an ingenious solution to variable volume from pump to keep carb-bowls filled. Lower number of pulses at idle results in little fuel flow. At higher-RPMs, there's more pulses/sec to pump more fuel to keep up with demands of higher revs. Extremely clever!!!

Ok, let's verify you don't have some sort of electrical problem.

1. pull headlight fuse
2. measure voltage at battery with everything OFF. Volts = ???
3. key ON
4. measure voltage on blk/wht wire at fuel-cut relay. Volts = ???
5. measure voltage on blk wire at ICM. Volts = ???
6. measure voltage at battery during cranking. volts = ???
7. check for sparks on #2 & #3 cylinders when cranking
 

Last edited by dannoxyz; Feb 2, 2023 at 12:33 AM.
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Old Feb 3, 2023 | 10:47 AM
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For testing that it is related to the Fuel Pump, you can bypass the pump and just run gravity feed to the carburetors. This is ok for low RPM and fuel flow. You'd want to verify that fuel is actually coming out of the petcock though naturally.
 
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Old Feb 11, 2023 | 07:22 AM
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Originally Posted by dannoxyz
If relay is running pump, but no petrol shows up:

1. is petrol leaving tank? petcock flows?
2. hose between tank pump not clogged?
3. hose before & after filtre not clogged?

Basically disconnect fuel hose at each junction and verify you have petrol flowing.
Originally Posted by IDoDirt
For testing that it is related to the Fuel Pump, you can bypass the pump and just run gravity feed to the carburetors. This is ok for low RPM and fuel flow. You'd want to verify that fuel is actually coming out of the petcock though naturally.
see this short wich I made

The petrol is leaving the petcock, i discovered the fuel filter clogged with rust, bought a new filter and I cleaned the fuel tank with Elektrolysis, I assembled everything and i see fuel going through the filter but at at very slow rate, I also feel the pump clicking every 1~1.5 sec. is that normal or is my fuel pump dead?
 

Last edited by Dutchnoskillz; Feb 11, 2023 at 07:52 AM.
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Old Feb 11, 2023 | 01:54 PM
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Is this with pump relay jumpered for full-power? Pump stops based upon back-pressure of fuel-line. If carbs are full, pump slows down and stops. Drain float-bowls and measure volume. If bowls are full, then pump is working fine.
 
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Old Feb 12, 2023 | 06:20 PM
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Originally Posted by dannoxyz
Is this with pump relay jumpered for full-power? Pump stops based upon back-pressure of fuel-line. If carbs are full, pump slows down and stops. Drain float-bowls and measure volume. If bowls are full, then pump is working fine.
This is indeed with the fuel system full, i did remove the fuel pump and drove but the it started sputtering and then died, vacuum hose from tank was kinked, after that drove fine until it died again on the main road. restarted and no issues, When i give full throttle in 6th gear while driving 80kmh it does not really like it idk why
 
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Old Feb 13, 2023 | 03:55 PM
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Originally Posted by Dutchnoskillz
When i give full throttle in 6th gear while driving 80kmh it does not really like it idk why
The bike needs the fuel pump in order to perform properly at higher speeds. Gravity feed doesn't supply enough fuel pressure to overcome the added air pressure from the DAI system.
 
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