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Discussion Starter #1
I have a CBR900RRP, some times it seems to flood. Ive noticed that when its running ok the fuel pump just pumps now and again. When it seems to flood the fuel pump is racing at tick over. Anyone no what the fuel pressure should be or what the fault is?

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maybe check the fuel pressure regulator, may have or starting to go bad, check your oil for smell of petrol.....
 

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Discussion Starter #3
As far as I know the pressure reg is integral with the fuel pump. This model has carbs.

Will check oil and let you know.

Cheers
 

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I have a CBR900RRP, some times it seems to flood. Ive noticed that when its running ok the fuel pump just pumps now and again. When it seems to flood the fuel pump is racing at tick over. Anyone no what the fuel pressure should be or what the fault is?

Cheers
Check the diaphram in the fuel tap.
 

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The regulator is not integral with the pump, it is under the seat. You might also have something in your carbs that is preventing the float bowl valve(s) from seating properly. That happened to mine not even 3 weeks ago. Fuel was coming out of the overflow tube, and the engine was running on 2 cylinders. Cleaned the carbs thoroughly and fixed the problem.
 

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Discussion Starter #6
Under the seat ! Fuel pressure regulator would have to be in the fuel line somewhere, so cant see it being under the seat. The voltage regulator is under the seat . Is that what you mean ????

Ive checked the oil no smell of gas but it was changed a few days ago. So probably wouldnt be any just now in any case.

The fuel tap is just a on-off tap....no diaphragm.

The bikes run fine today....but the pump is pumping at normal speed.

I did notice that when i turned the fuel tap off when it was flooding it cleared. But came back when i turned it on again. But the pump was racing then.
 

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Under the seat ! Fuel pressure regulator would have to be in the fuel line somewhere, so cant see it being under the seat. The voltage regulator is under the seat . Is that what you mean ????

Ive checked the oil no smell of gas but it was changed a few days ago. So probably wouldnt be any just now in any case.

The fuel tap is just a on-off tap....no diaphragm.

The bikes run fine today....but the pump is pumping at normal speed.

I did notice that when i turned the fuel tap off when it was flooding it cleared. But came back when i turned it on again. But the pump was racing then.
It definately sounds like the fuel pump is not pressurising so maybe the pump is on the way out.
It doesn't explain the flooding though as the fuel flow should be stopped by the needle valves in the float bowls. I'd start with replacing the needles and seats since they're probably worn anyway.
 

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Discussion Starter #8
Well my thoughts were with the pump racing it was over pressurising, which made the fuel leak passed the float valves. I know carbs cant take more than 5 psi or so or it gets passed the valve.

I just wanted to no what the fuel pressure should be, im guessing at 2 to 3 psi would be normal. But its hard to read the pressure when the problem occurs as im usually riding it. Then it goes away.
 

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Well my thoughts were with the pump racing it was over pressurising, which made the fuel leak passed the float valves. I know carbs cant take more than 5 psi or so or it gets passed the valve.

I just wanted to no what the fuel pressure should be, im guessing at 2 to 3 psi would be normal. But its hard to read the pressure when the problem occurs as im usually riding it. Then it goes away.
It may be possible but it would still indicate a problem internally in the pump as it must have built-in pressure regulation.
I don't know how much pressure the needle valve can withstand but I would expect worn needles to withstand significantly less pressure than good ones. On a fifteen year old bike I'd recommend replacing them anyway. If the problem still exists then I'd have to suggest having the pump pressure tested somehow. It'd also be worth cleanign the float bowls out as there may just be crud in there keeping the needles from sealing fully sometimes.
 

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Discussion Starter #10
Ive already put new float needle valves in along with new needles and jets etc. And i must admit its not as bad as it was before i put the new float needle valves in.
 

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Ive already put new float needle valves in along with new needles and jets etc. And i must admit its not as bad as it was before i put the new float needle valves in.
Then I guess the next thing is to have the pump tested.
Unfortunately, I don't have a manual to give you the specs for it.
I checked the F2 manual but that's got bugger all info as well.
Being a sporadic problem though it could be hard to find it by testing. At that age it's probably worthwhile replacing it anyway though.
 

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Under the seat ! Fuel pressure regulator would have to be in the fuel line somewhere, so cant see it being under the seat. The voltage regulator is under the seat . Is that what you mean ????

Ive checked the oil no smell of gas but it was changed a few days ago. So probably wouldnt be any just now in any case.

The fuel tap is just a on-off tap....no diaphragm.

The bikes run fine today....but the pump is pumping at normal speed.

I did notice that when i turned the fuel tap off when it was flooding it cleared. But came back when i turned it on again. But the pump was racing then.
Sorry, you're right. I was thinking of the fuel cut relay. It could be that.
 

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Oh yes. Does that cut the pump in an accident? Its been runnin fine for the last few times ive been on it.
I think it cuts power to the pump whenever the engine stops running.
 

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Discussion Starter #16
Oh yes ok. That makes sense. Because fuel may trickle into the cylinders if the fuel is still being pumped when its not runnin. Its amazing how many faults come up on a old bike. You wouldnt get these on a new one, guess thats why the agents havent a clue.

I did notice it was jumpin out of 2 nd gear the last time i rode it.
 
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