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Discussion Starter · #1 ·
Been working on this bike for a while now when I have a spare moment.
The original problem was bike cut off after a ride and would not start back until I pulled the battery negative and replaced it. I had gotten into a rain storm. Let everything dry out. Wouldn't start again, but now the fuel pump doesn't prime.

What I have done check so far.
Main fuse-good
Ignition fuse-good
Ohmed out fuel pump- bad-replaced.
battery voltage- 12.5v
New fuel filter
carbs cleaned.

Current state- Bike turns over but does not start. Fuel pump still doesn't prime. Thinking about changing the starter circuit relay on it. any advice would be nice. Thanks.
 

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I ride my wife and her R6
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It's a fuel injected bike, a gravity feed won't work, you need the pump to pressurize the rail.
One of your safety interlocks isn't working.

Gear position switch, kill switch, sidestand switch. They all have to be working for the pump to prime. If the ecu doesn't get signals from them it wont turn on the pump or the injectors.

I know the battery checks out at 12.5v but charge it anyway and test it as you engage the starter. If it drops below 10v it's hooped.
 

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Big ol pile of them bones
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1,620 Posts
Been working on this bike for a while now when I have a spare moment.
The original problem was bike cut off after a ride and would not start back until I pulled the battery negative and replaced it. I had gotten into a rain storm. Let everything dry out. Wouldn't start again, but now the fuel pump doesn't prime.

What I have done check so far.
Main fuse-good
Ignition fuse-good
Ohmed out fuel pump- bad-replaced.
battery voltage- 12.5v
New fuel filter
carbs cleaned.

Current state- Bike turns over but does not start. Fuel pump still doesn't prime. Thinking about changing the starter circuit relay on it. any advice would be nice. Thanks.
If the starter relay was bad, it wouldn't crank over. Have you tried spraying carb cleaner or starting fluid directly into the carbs to get it to fire?
 

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I ride my wife and her R6
Joined
·
101 Posts
Been working on this bike for a while now when I have a spare moment.
The original problem was bike cut off after a ride and would not start back until I pulled the battery negative and replaced it. I had gotten into a rain storm. Let everything dry out. Wouldn't start again, but now the fuel pump doesn't prime.

What I have done check so far.
Main fuse-good
Ignition fuse-good
Ohmed out fuel pump- bad-replaced.
battery voltage- 12.5v
New fuel filter
carbs cleaned.

Current state- Bike turns over but does not start. Fuel pump still doesn't prime. Thinking about changing the starter circuit relay on it. any advice would be nice. Thanks.
If you know most of this, don’t take offense, I’m just making sure we are both on the same page.

The starter circuit cutoff relay (item 9 on the diagram) could be the problem.
There are 2 relays in there, one for the fuel pump and one for the start button (it’s the one on the left on item 9, the one on the right is the fuel pump relay).
Since the engine is turning over I don’t suspect the starter button relay.

I DO suspect the fuel pump relay or the diode inside the starter circuit cutoff relay.
For the fuel pump to work the fuel pump relay gets a ground signal from the CDI via the Blue/Red (L/R) wire which energizes the relay starting the pump.

The Neutral switch has to work to make a ground to start the bike without the clutch in.
The side stand switch and the clutch switch need to work if you want to start it on gear.

That being said, test all of the mentioned switches and relays to make sure they work.
Also, hardwire the pump and test it as well.
Test the diodes in the starter circuit cutoff relay. The Sb wire gets it’s signal from a few places through the diode inside the starter circuit cutoff relay, I’m not sure if the diode fails in the open or closed position.
If the CDI doesn’t get the right signal from the Sky blue (Sb) wire, it will not energize the fuel pump relay and bikey no starty.

The diagram below is colour coded as follows.

RED is the starting circuit.

GREEN is the side stand and clutch circuit, the clutch switch is cut off at the bottom of the pic

BLUE is the fuel pump circuit

SKY BLUE is the neutral switch and CDI

I really hope this helps, sorry about the mixup with the later gen bikes. Cheers, Mike.

 

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Discussion Starter · #10 ·
If the starter relay was bad, it wouldn't crank over. Have you tried spraying carb cleaner or starting fluid directly into the carbs to get it to fire?
My miscommunication. starting circuit cutoff relay*

Here is some more to look at. :popcorn:







Thank you for all the info. I hadn't found the upper diagram. Guess I didn't search deep enough. I ordered another relay. Gonna try that and update once it gets here. I went thru all the manuals trouble shooting steps except for that relay because I didn't have the listed tester and I was afraid to put straight batter power to it. Didn't know it it could handle the current.

Thanks again.
 

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Discussion Starter · #11 ·
Update. Replaced battery, and starting circuit cutoff relay, and pump still doesn't come on. Pump ohms out to 2.7 ohms slightly under spec but not by much. I checked voltage across the wiring harness plug for the fuel pump and i'm getting 9.9-10v~. Battery at terminals reads 12.99v. I know there should be some drop from point a to b, but really that much? any suggestions? Im at a point of maybe parting this thing out since I can't get anywhere with the electrical system. I know why I bleed green!
 

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Discussion Starter · #12 ·
Took apart and cleaned all terminal connections thruout the circuit. Reading 10.8v now to the pump connector. Tried testing used pump off of bike putting it to a know good battery and it wont turn dry or with fluid. Assuming the used pump I picked up is bad. Going to try a used china knock off pump to prevent throwing to much more money at this bike.
 

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Discussion Starter · #13 ·
Update: Started bike using gravity feed. All functions well. Took all connection from circuit loose and added dielectric grease. Amazingly now getting 11.5 volts. Replaced used oem pump with aftermarket china knock off and it runs great. Thanks for all the help.
 

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Big ol pile of them bones
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Update: Started bike using gravity feed. All functions well. Took all connection from circuit loose and added dielectric grease. Amazingly now getting 11.5 volts. Replaced used oem pump with aftermarket china knock off and it runs great. Thanks for all the help.
So the fuel pump was the culprit, good to know.

Are you getting the 11.5v at the battery or the fuel pump plug?

For comparison, I tested my battery this morning (hasn't been started in a week):

Not running:


Running on choke (high idle around 2500):
 
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