[Jay_G]

Hey guys,

I have come across a problem with my 95 Aus CBR900RR.

riding along and it started feeling like it was starving of fuel, like when it starts coughing before switching to reserve. then it would completely die, i would pull over to the side of the road let it sit for 20 or so seconds crank for a bit and it would fire back to life. this happened about 4-5 times in a 10 km stretch.

I assumed it would be a fuel pump problem so i started it up checked charging voltage at the battery and it was 13.8V. unplugged the pump and checked the voltage at idle and it was around 15.8 and peaked at 16 volts. Plugged it back in and probed the back of the plug and got about 9.6 volts at idle.

so i am thinking this will be causing the pump to heat up and stop working, the weather has been very warm here.

any one experienced this problem before? a couple of terminals on the reg rec look a bit burnt but i find it strange that its still?

some help would be appreciated.

 

[bladeracer]

Sounds like tank vacuum.
When it happens, pop the cap and listen for a big gulp of air indicating the tank vent is blocked.

 

[Jay_G]

I had a bit more of a tinker this arvo, not a tank problem, it completely failed in the driveway and wouldn't start even with the tank open. i think its a pump related problem, but another interesting/annoying development that i will have to look into is the 3 yellow leads going to the reg are getting very hot and the old tape that was wrapped around the terminals had burnt and become brittle the stator seems to be putting out equal voltage on all terminals and its still charging the battery at the correct volts but some of the pins in the plug to the reg/rec have been burnt and the plastic around melted., would a reg problem be causing this excessive heat?

 

[unfetteredmight]

I had a bit more of a tinker this arvo, not a tank problem, it completely failed in the driveway and wouldn't start even with the tank open. i think its a pump related problem, but another interesting/annoying development that i will have to look into is the 3 yellow leads going to the reg are getting very hot and the old tape that was wrapped around the terminals had burnt and become brittle the stator seems to be putting out equal voltage on all terminals and its still charging the battery at the correct volts but some of the pins in the plug to the reg/rec have been burnt and the plastic around melted., would a reg problem be causing this excessive heat?

Here's what keeps bugging me, you have an electric fuel pump? I didn't think a 95 used an electric fuel pump, my 96 doesn't. Or did I read that wrong in your first post?

Excessive current or excessive resistance both can melt wiring, it's your job to determine which is happening. If I knew exactly which pins were melted I could give you a hypothesis. The worst thing one can do is start swapping parts out until something is fixed, it's an expensive repair method and can lead to you replacing parts more than once.

Reminds me of replacing an old style Ford alternator with a separate voltage regulator. If the field circuit is shorted on one it can and probably will take the other out, so you can swap a bad alternator out with a good one and as soon as you apply voltage the bad regulator would take out the alternator or vice-versa. Both had to be replaced at the same time, Ford cured that problem by combining the two, but it was a real PIA if you were new and didn't know better, or just liked to swap parts out without testing.

You need to get a wiring diagram and a digital multimeter with a 10 mega ohm impedance, both investments that will pay dividends in the long run.

 

[Jay_G]

i tracked it down to a fuel pump problem, pulled it out and hooked it directly up to 12volt and it was sticking. i have bypassed it for the time being and will be tracking another down. possibility that the pump sticking was causing excessive current draw and causing wires to get hot, its also been 35-40 degrees C here.

 

[unfetteredmight]

i tracked it down to a fuel pump problem, pulled it out and hooked it directly up to 12volt and it was sticking. i have bypassed it for the time being and will be tracking another down. possibility that the pump sticking was causing excessive current draw and causing wires to get hot, its also been 35-40 degrees C here.

Quite feasible....

But an electric fuel pump on a 95? Isn't that year carbed?

 

[eye toke]

my 88 600 hurricane had a low pressure fuel pump.they dont have to be fuel injected to have a pump.

 

[unfetteredmight]

my 88 600 hurricane had a low pressure fuel pump.they dont have to be fuel injected to have a pump.

Fair enough, but I'm perplexed because my 96 doesn't use a pump.

 

[eye toke]

are you sure it does not have a low pressure fuel pump?

 

[jaraxle1zx]

95 has a fuel pump. think 95 n down

 

[unfetteredmight]

are you sure it does not have a low pressure fuel pump?

It doesn't use an electric one, that I know for sure.

 

[bladeracer]

But an electric fuel pump on a 95? Isn't that year carbed?

'92-'95 has a fuel pump. '96-'99 does not.
Fuel pumps are used when the fuel level in the tank is below the level of the float bowls - regardless of whether it's injected or carbureted.

 

[unfetteredmight]

'92-'95 has a fuel pump. '96-'99 does not.
Fuel pumps are used when the fuel level in the tank is below the level of the float bowls - regardless of whether it's injected or carbureted.

Ahh I see, makes perfect sense now. Thanks

 

[eye toke]

anybody know why they dont have a fuel pump from 96-99? is the tank always above carbs? just wanna know.thanks.

 

[bladeracer]

anybody know why they dont have a fuel pump from 96-99? is the tank always above carbs? just wanna know.thanks.

That's the only reason that makes sense. The early ones will run fine without the pump until the fuel level gets too low to feed the carbs by gravity but I don't know how close you can get to empty before it stops sucking fuel.