NC750X 2017 Engine won't start (Fixed)

[Mark Mitchell 23]

This is the first time I have ever posted, as I tend to be the person that reads all this stuff, however on this occasion I fixed my bike so thought it would be good to post for the benefit of the community.

 

About six weeks ago, I had an issue where my bike struggled to start from hot, however it did eventually burst into life but was obviously not well! The problem persisted until two days before it was due to go for the MOT. I tried starting but all it would do was spin the engine over and as you do on these occasions, I flattened the battery. In a rush to get the bike going I bought a new battery, however I should have just waited and charged it overnight, as the original was fine.

 

I then spent a night of searching the forums and unfortunately this led me down a path of not trusting my own expertise and thinking that some kind of modern electronics problem might be fault that only a Honda dealer could fix. I rang my local bike GURU (the MOT man) who told me to go back to basics and check for spark and fuel, wise words.

 

Lesson 1, spin the engine over a few times and remove a spark plug, if it's wet it's an ignition problem if it's dry its fuel, basic stuff eh. I did this and also checked there was a spark (there was) and the plug was dry as a bone, so it must be a fuel issue.

 

When I switched the ignition on, there was a noise which I assumed was the fuel pump (more on this later) so I thought there might be a blockage in a fuel filter or a kinked pipe.

As many of you know, getting at the engine on an NC is not as simple as most bikes, so with the help of YouTube I spent some time removing the left and some right side panels, nothing to see here other than a few additional wires and relay for the 12 Volt socket and the day running lights, which I fitted when the bike was new.

I then thought that I would feel much more comfortable if I could hear the engine running, so I removed the air filter (with the help of YouTube) and sprayed easy start (Diethyl ether) into the air intake. I then tried starting the engine and it burst into life and ran and continued to run even when the easy start had been used up. I switched the engine off and then the ignition back on and noticed another noise namely that there was a fuel pump sound from inside the tank.

 

Lesson 2, when you switch the ignition on (kill switch in the go position and in neutral etc) there should be a fuel pump sound from the tank area.

 

Lesson 3, what was wrong?? There is a connector behind the left hand side panel, approximately behind the 750X sticker, it provides a feed to the fuel pump this was not properly snapped together, hence causing an intermittent fault, which eventually proved terminal.

 

What caused the fault, I can't imagine the boys at the Honda factory failed to snap the connector together, it was more than likely caused by me when I had the left hand side panel off to fit the 12 Volt socket, however this was three years and 6000 miles ago, but I will still put this down to my own stupid tax!

 

The moral of the story, I don’t think this fault would have appeared on Honda’s diagnostic tool, hence you are just as competent to trace faults with the help of common sense and YouTube. Also bad connections can take years and many miles to materialise.

 

I suspect the only edge the dealer would have over the amateur, is that they may have seen the same problem before.

[ChrisCB 6,672]

First post and first "thanks" 

 

Well done sorting it out and it may well help others 👍

[Grumpy old man 4,678]

Thanks Mark. Keep on posting 👍

[MatBin 5,085]

Nicely sorted. I believe dealers have a check list which they go through religiously, so they may well have found it but as quickly as you, who knows?

[Andy m 23,540]

Nice bit of diagnostic work. Thanks for posting. 👍

 

Andy

[Defender 3,837]

Well done for finding that, writing and posting it up, plus admitting it was most probably your fault, following the sequence of events is a good way of working, in many/most cases it's somewhere you've been working especially if it was working perfectly well before you started?

[Mark Mitchell 23]

Cheers Gents, I appreciate your support. Mark.

[Henrik Boensvang 9]

Hi Mark,

 

Your problem sounds a lot like mine. I talked with my mechanic on the phone and he suspects a cable to be undone somewhere. Do you have a photo of where the connector you had trouble with is? 

 

Thanks.