Running issue

[Bruce R]

I have an issue with my Gen 1 that I am hoping someone could give me some guidance on.
When I turned on the ignition this morning I did not get the usual whirr/clicking of the v-boost servo test and fuel pump topping up the carbs. No noise whatsoever.
It started ok but then it coughs and splutters and cuts out when riding it, feel like from fuel starvation.
Any assistance anyone can provide to help diagnose the issue would be much appreciated.

 

[Radioguylogs]

Based on the quiet startup, I'd check the battery voltage first- might a bad battery or failed regulator.

 

[Bruce R]

Based on the quiet startup, I'd check the battery voltage first- might a bad battery or failed regulator.

Thank you for the prompt response. I had a slight misdiagnosis. When I listen carefully I can actually hear the vboost whirring when I turn on the ignition. It's just the fuel pump that does not kick in. I'm guessing that I might have a faulty fuel pump or fuel pump relay?

 

[Radioguylogs]

Could be fuel. Do you know how to check the fuel pump and relay?

However, one thing easy to rule out is the kickstand switch. Last spring my 1st gen was behaving same as yours, and it turned out to be the kickstand switch. I cleaned it with Deoxit and life was good again with little effort.

 

[MaxMidnight]

If it was the side stand switch or relay wouldn't that stop the engine?

Bruce, as the systems are different depending on the year of bike it would be helpful if you added (at least) the year of the bike on your signature.
What happens if you run it with the switch set to 'reserve'?
Have you checked if there is any fuel in the float bowls?

 

[Fire-medic]

it would be helpful if you added (at least) the year of the bike on your signature.

Yes, please! All members. please follow the suggestion of Mr. Midnight.

https://ia800204.us.archive.org/14/...ice-manual/yamahavmaxvmx12-service-manual.pdf

Another file for the service manual, the page numbers are different.

https://data2.manualslib.com/pdf7/1...x12_2001.pdf?78d960b0d2fbe67346bfd7a39ef24837

 

[Bruce R]

Thank you all for your input.
I’ve sorted it . . but I have no idea how.
I removed the fuel pump and hard wired it to the battery to check and it was working fine, so I reinstalled it, started the bike and checked it was pumping fuel by inspecting the glass fuel filter that is in the bike. Hopped and took it for a run and it was running perfectly. Really weird. Thank again for the feedback. Much appreciated.
The bike btw is a 1992 v-max

 

[Radioguylogs]

"If it was the side stand switch or relay wouldn't that stop the engine?"

Actually, my bike would suddenly cut out and miss while I was riding. It would usually continue running after that.

 

[Fire-medic]

The Deoxit used for the sidestand switch cleaning is the right thing for the job, if it allows the sidestand switch to work properly. I get similar results with WD-40 on the sidestand switch.

Bruce R, as long as it works, ride and enjoy. Hopefully it will not re-occur.

Anyone facing replacement of your OEM fuel filter for the Gen.1's take your OEM filter to the local auto parts store, and match it up to what they have, it's a common size, and you don't need to spend OEM parts pricing for one. The generic replacement should be < 1/2 of OEM.