Can't Start my '93 K75 after 18 months off road

[850Commando]

Hi - My K75 has been 'off the road' for 18 months undergoing a mild 'make over' (catalogued elsewhere on this site).  Fuel tank was never removed or drained.  Tried to start it today - All dash lights are as normal - Battery fully charged - Starter motor spins but motor does not fire up.. not even a bit).  I can't hear the fuel pump priming (on a Triumph I hear the fuel pump buzz when the ignition is switched on)..  I cannot remember if the brick should do the same?  Any advice as to where to look first would be appreciated.. Thanks 

   

[Laitch]

You'll hear the fuel pump whine for a couple of seconds when you release the starter button. It isn't energized by turning the key to On.

Have you ridden this moto or heard the engine run? I can't determine that from your previous posts. Any used bike with an unknown maintenance history should have the fuel tank emptied and inspected, the fuel filter and fuel tank lines replaced, at a minimum. That's your starting point. Let us know what you find.

[850Commando]

Hi Laitch - I rode it around for a year or so before the 'make over' - It went really well - always started and engine ran smoothly..  (I didn't empty the tank when I started as I hadn't figured on this taking 18 months..) - Just tried again and cannot hear any whine from the fuel pump...  I'm guessing that's where I need to start looking?

[Laitch]

Just tried again and cannot hear any whine from the fuel pump...  I'm guessing that's where I need to start looking?

Replace the fuel pump fuse—#6 counting from the top. Check function. Check the four-pin connector on the right side of the moto below the tank for continuity and for a tight connection. Check function. If still no go, remove the fuel cap assembly and the fuel pump then bench test the pump.

[850Commando]

Laitch - You are a genius.. Just pulled the 6th fuse down and tested it on a multi-meter and it's dead.. (As the bike was running before, any idea what would have caused this fuse to blow?) 
I was going to ask you why, on my bike fuse 5 (labelled 'Sonder') is missing and if you knew of an English translation of the fuse titles - but I thought, before asking silly questions I would Google it - The Google result led me to an image you had posted on this site in 2013) - Thanks again!   

[Laitch]

Just pulled the 6th fuse down and tested it on a multi-meter and it's dead.. (As the bike was running before, any idea what would have caused this fuse to blow?) 

Age and corrosion can cause a fuse to blow. Don't start celebrating yet. Celebrate if the replacement doesn't blow again soon. In the meantime, clean the four-pin connector that supplies current to the pump, be certain it's tight then drain and inspect the tank.

Go to the service manual section then download the K75 riders manual and the K75/K100 workshop manual.

[850Commando]

Hi - I looked at the 4 pin connector - It looks ok with no corrosion and is tight. I need to obtain a 7.5 amp fuse so whilst I wait for that I'll drain the tank and will check out the manuals.. Thanks 

[volador]

[850Commando]

Thanks Volador

[volador]

Easter Beaver Sumitomo TS090 Sealed Connectors

the 'Sumitomo Not in Catalog Male 4P Connector'  3/4 of the page down sleek discreet connector if you chose to replace the OE 4-pin connector

get extra pins and seals

[850Commando]

Thanks again Volador - These plugs look good

[volador]

Thanks again Volador - These plugs look good

please make donation to 'volador espresso & profiterole fund'... committed to achieving positive outcomes for every MOE...

patreon, venmo, paypal, bitcoin, libra, gladly excepted

[850Commando]

Hi Laitch - As you correctly observed my celebration was pre-mature - Having obtained some spare 7.5 amp fuses these blow the moment the starter button is pressed..  so I went back to your advice - checked the 4 pin connector and I see the next step is to drain and 'inspect'  the tank..  Can you give me any guidance as to what I might be looking for or how to test the pump? My 'make over' has been a quite superficial job and didn't involve removing the tank or interfering with the wires going to the fuel pump so it seems strange that this fault should have happened (the bike was running fine before) - any advice will be appreciated - Thanks   

 

[The Mighty Gryphon]

Does the fuse blow if the tank connector is disconnected?

[850Commando]

Hi M-G - No, with the four pin electrical plug disconnected the fuse does not blow...

[Laitch]

I'd remove the fuel pump then bench test it with a 12 volt battery to determine if it's seized. Disconnect the moto's battery ground wire. Remove the fuel cap assembly, drain the tank using a bulb siphon, disconnect the wires from the pump, disconnect its fuel hose and filter basket vent hose (if it has one, some pumps have a filter sock instead), squeeze inward on the tabs securing the pump holder to its platform then withdraw the holder and pump together.

Take photos of how the pump is oriented in its holder; post them here.

[Paul_Waterloo]

If you need any pictures of the pump in the tank, I got some good ones when I put my tank back together. Does sound like something wrong with the pump.

[The Mighty Gryphon]

A seized pump will draw a lot of current, enough to blow the fuse.  I agree that is probably where the problem is.

[850Commando]

Hi Guys - Thanks a lot - I'll get going on that first thing tomorrow and let you know   - I've watched  You Tube video so I think I know what to do (Paul - I'll shout if I need those photos) ..  I assume a seized pump means a replacement is needed?  (I'm guessing they are nor serviceable)   

[Laitch]

I assume . . . I'm guessing . . .

I believe the less assumption and guessing are brought to bear on any moto task, the sooner the task will be completed. Many a seized pump has been brought back into action by soaking in solvent and reversing polarity. A search of the site will reveal that. I'd probably replace a seized pump if I could afford a replacement.

[volador]

or your petrol level sender is f-ed up and shorting out

you can take fuel pump & simmer in hot water to free up any congealed material or soak in ethylene alcohol, lacquer thinner, kerosene or vinegar

[850Commando]

Thanks everyone - pleased to say it's sorted - I took out the fuel pump and bench tested  it with a spare battery - Very defiantly seized .. Tried tapping it it with a wooden hammer but no good so I thought - nothing to loose and reversed the polarity.. Just brushed the battery terminals momentarily a few times - on the third or fourth try the unit buzzed so I swapped back the terminals and it ran perfectly.. Now back in the bike and it started okay and runs smoothly..     Thanks again..

20200509_111835.jpg (29.58 kB . 768x373 - viewed 420 times)

[Laitch]

Is your pump's pre-filter a fine-mesh basket or a flexible sock?

[850Commando]

Hi Laitch - It's a flexible sock:

[volador]

looks like a healthy OE petrol pump and rubber vibration damper

OE petrol pump should say 'VDO' on bottom (VDO- manufacturer)