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1Back to top Go down    Fuel dump after motor non start on Fri Sep 23, 2016 4:47 pm

audibob

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Hi all.
The other day a delivery chap saw my bike in my garage and after a discussion about the K bikes, I used the first stage of the "choke but not a choke " lever and started the motor. As she had not been run for a week or so, she took an extra couple of turns and then fired up. I then switched her off after ten seconds or so.
Today having got all my gear on for a ride, she turned over but would not start.
Hmm great I thought.
She also dumped fuel on the drive from around the rear cylinder No 4
The battery was checked and showed 11.98 volts not ideal but enough I thought.

I took the plugs out and all four were wet, so fuel was okay.
I dried them, refitted and tried again , but again, no response.
Plugs dried again and checked for spark, and all four zapped.
Removed fuel pump connector, plugs, and spun motor to dry the cylinders.
Refitted some old plugs I used , and spun the motor with the fuel pump disconnected, and she tried to run.
Connected fuel pump connector and with a wot throttle she eventually cleared and ran fine afterwards.

so. 2 questions.

1. Why the initial fuel dump. I have no obvious fueling issues / leaks and she runs strong and economical.
2. As my Coolant temperature sensor is original, could it be putting excess fuel in when cold , meaning I inadvertently flooded the engine when I ran her for just a moment.


I will change the battery at some point
Has anyone else come across this ?
Thanks
Bob


__________________________________________________
Yamaha 90
Honda CD 175
Honda CB 360
Triumph T 140V Bonneville
Triumph T150 Trident
Honda CB750 F1
Cz 175
Yamaha XS 750
R 100/7
R 80
K100 LT
K100 LT current bike
    

2Back to top Go down    Re: Fuel dump after motor non start on Fri Sep 23, 2016 5:40 pm

Laitch

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@audibob wrote:Has anyone else come across this ?
It's not an unusual tale, Bob. I think in your case your battery needs more output and when it has it, your bike will start.

You can burn off the fuel in the drive to amuse the neighborhood children.

    

3Back to top Go down    Re: Fuel dump after motor non start on Fri Sep 23, 2016 6:31 pm

kennybob

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Was the tank overly full of fuel?

There is an air vent line that exits from the tank bottom that may have functioned as an over-flow to dump some fuel--the hose runs down the right side frame toward the rear, or drips onto the air filter housing and runs off near the #4 cylinder if on the side stand.

    

4Back to top Go down    Re: Fuel dump after motor non start on Fri Sep 23, 2016 7:25 pm

Holister

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Fuel coming out of the headers at start-up is typical of the temp sensor losing its earth contact. Maybe a bit of corrosion around the sensor thread. Test the resistance on FICU pin 10 & 13, particularly if it happens again.
You could also check/clean the FICU plug contacts or the plug can be a little loose. Loss of continuity on one of those pins will have the same effect.


__________________________________________________
1988 K100RT VIN No. 0094680
1989 K100RT VIN No. 0097367 (naked)
1996 K1100RS VIN No. 0451808
Fuel: 95 Octane
Engine Oil:Nulon Full Synthetic 15W50
Gear Box Oil: Nulon Synthetic 75W90
    

5Back to top Go down    Re: Fuel dump after motor non start on Sat Sep 24, 2016 4:11 am

audibob

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Thanks for the replies.
The fuel dump saved me time weeding my drive, and the fuel tank was only half full.
I have never seen an overflow even when filled to the brim, so Holisters comment about the Coolant temp sensor seems right, as I have noticed the green muck around its threads. It is 27 years old after all.
I intended to replace it along with the sensor for the Temperature Gauge.
A new Thermostat will go in during December, along with a nice set of 1100 throttle bodies.
I will check the battery voltage regularly ,and the Alternator output, and replace as necessary.
Thanks again .
Bob


__________________________________________________
Yamaha 90
Honda CD 175
Honda CB 360
Triumph T 140V Bonneville
Triumph T150 Trident
Honda CB750 F1
Cz 175
Yamaha XS 750
R 100/7
R 80
K100 LT
K100 LT current bike
    

6Back to top Go down    Re: Fuel dump after motor non start on Sat Sep 24, 2016 6:38 am

Dai

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@audibob wrote:along with a nice set of 1100 throttle bodies.
Don't forget to advance the timing by six degrees when you do that. Makes a helluva lot of difference! Very Happy


__________________________________________________
'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

7Back to top Go down    Re: Fuel dump after motor non start on Sat Sep 24, 2016 1:33 pm

audibob

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Thanks Dai.
I will advance the timing first to see the difference before fitting the bigger throttle bodies, cant wait ......


__________________________________________________
Yamaha 90
Honda CD 175
Honda CB 360
Triumph T 140V Bonneville
Triumph T150 Trident
Honda CB750 F1
Cz 175
Yamaha XS 750
R 100/7
R 80
K100 LT
K100 LT current bike
    

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