Anyone good with motorbike electrics?

#1
Specifically a 2001 CBR 939 blade?

My fuel pump has stopped priming when I turn the key. Cutting a long story short it died after a days riding. Pulled over, switched the engine off using the kill switch, went to start and it wouldn't. If I run power directly to the pump it fires up.

Do far I've tested:

BAS- good
Fuel cut off relay- good
Ignition relay- good
Kill switch- good
HISS connection/different key- good
Main earthing point and block- good
All fuses- good
Clutch switch- good
Sidestand switch- good
Fully charged battery- good

I'm stumped. Saving at the moment to put it into a garage but just want to pick an outsiders brain. A point to note is that I have power going into the relay but no power coming out (problem with the ECM?).

Cheers guys.

TBM
 
#2
You may get more luck with a blade specific forum as this may be a unique issue that is common to this model.

But.......

If you have power into the relay and nothing coming out, why do you say the relay is good?
 
#3
Tried blade forums but although it seems to be a common problem, no one has a solution. Or at least one they'll share.

Swapped the relays over and the same thing happens. Also ran power through it and it clicks on/off (open/closed).
 

Ravers

LE
Kit Reviewer
Book Reviewer
#5
I'm not too sure about bikes but I had a car with the same problem a few years back (Lancia Kappa Coupe, Alfa 3 litre V6 lump). The RAC man got into the boot and twatted the floor above where the fuel pump was located with a lump hammer while I turned the engine over.

It worked. Try giving your fuel pump a decent clout, might sort it.
 
#7
If there is a fault on the ignition system then when you turn the bike on the earth could be live. This could effectively put a ghost fault in the pump as the earth wire will be carrying voltage. 12v at both ends-instead of 12v in, through the component and earth out. Look at a wireing diagram and see if the ignition relay shares a common earth with another component.
 

Grumblegrunt

LE
Book Reviewer
#8
have you been all over it cleaning the contacts, 10 year old bikes generally start going green. most of the fuel pump issues I come across are due to bad contacts not letting enough current through.

you could patch it through an ignition live or a switch and run it like that for a bit.
 
#9
DM,

That close-down is a whole other debate! I have been told not to use the killswitch by about eaqual numbers of mechanics who have told me to use the kill switch. Either way , kill-switch or key, the basic effect is the same. Its like having a computer with the option to switch the plug socket off at the wall or pull the plug out of the socket. There is no "soft" close down routine.

I have known GGs answer to be the case in a number of confusing electrical quandries - power getting through enough to register on a meter and fool you into thinking the circuit is good but just not quite enough or reliably enough for correct functioning of whatever it may be.
 
#11
There is a box on the bike that cuts the engine when it crashes/falls over. This went on my GSXR750 and gave the exact same symptoms. Can't for the life of me think what it's called though. I replaced it with one off eBlag and it did the trick!
 
#13
DM...................I have known GGs answer to be the case in a number of confusing electrical quandries - power getting through enough to register on a meter and fool you into thinking the circuit is good but just not quite enough or reliably enough for correct functioning of whatever it may be.
You could try a test lamp. It draws current and will indicate as an open circuit under those circumstances..
 
#14
There is a box on the bike that cuts the engine when it crashes/falls over. This went on my GSXR750 and gave the exact same symptoms. Can't for the life of me think what it's called though. I replaced it with one off eBlag and it did the trick!
That's a BAS (bank angle sensor) on a Honda.
 

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