VFR800 - not starting, any help gratefully received

[rcsyoung]

Hi All

I replaced my broken rear subframe yesterday and all was going fairly well until I went to start the bike. If you know the VFR you'll know that there is a noice when the ignition is turned on as (I assume) the fuel pump/injection is primed/checked. There was no such noise and unsurprisingly the bike won't start.

I think that everything was plugged back together properly but I did find the following not attached to anything. It looks pretty fundamental but I can't see where the hell it should be plugged into.




Does anyone have any suggestions?

Thanks in advance...

[GazzaMogzy]

Not breather pipes are they by any chance?

[p1neil]

It may sound a bit obvious but have you checked your kill switch isn't in the off position, as for the pipe this may be a separate issue, I would have thought that you would still get the fuel pump noise whether the pipes are attached or not.

[rcsyoung]

It's not the kill switch and I suppose it may just be a breather pipe in which case I'm screwed as it means taking the whole thing apart again to see what's not working.

[N Dentressangle]

Any dash lights when you switch the ignition on?

[rcsyoung]

Yes - there is power, all of them come on as usual. I'll have to double check if the FI light stays on though.

[N Dentressangle]

rcsyoung said:

Yes - there is power, all of them come on as usual. I'll have to double check if the FI light stays on though.

That still smells somehow like a kill switch fault or similar though, doesn't it? Any click from the starter when you press the button?

I wouldn't have thought that missing pipework would cause the symptoms you have - it's more likely you'd disturbed something electrical, isn't it?

[rcsyoung]

N Dentressangle said:

That still smells somehow like a kill switch fault or similar though, doesn't it? Any click from the starter when you press the button?

I wouldn't have thought that missing pipework would cause the symptoms you have - it's more likely you'd disturbed something electrical, isn't it?

Agreed. The started motor will turn over it just won't fire - presumably because the fuel pump isn't pumping. If that pipe is for fuel and not an overflow then its possible that there is some sort of safety cut out...? Otherwise I can only assume that something in and amongst the electrics is not plugged in to where it should be.

:-(

[N Dentressangle]

rcsyoung said:

Agreed. The started motor will turn over it just won't fire - presumably because the fuel pump isn't pumping. If that pipe is for fuel and not an overflow then its possible that there is some sort of safety cut out...? Otherwise I can only assume that something in and amongst the electrics is not plugged in to where it should be.

:-(

The loose pipe looks more like a vacuum pipe than anything else. Might cause rough running, but not fuel pump u/s.

Fuel pump fuse or wiring to it from the front - back of the bike all ok? They normally sit in the tank - dislodged spade connector? You could always pull the comnnectors off it and see if it's getting current?

[Biker's Nemesis]

Turned the fuel back on?

[3doorPete]

I would take off and clean all connectors around the fuel pump and trace back to ECU - unplug and replug everything around the ECU, using switch cleaner/lubricant. Check fuse too.

You can test it with everything off the bike as you are just listening for the fuel pump priming when you turn the ignition on. No noise, no worky.

[Heretic]

Ok, not knowing what year, so I am going to take a guess

some of those had a vacuum operated petcock (fuel valve out of the tank) for safety reasons. If no vacuum to this valve, no fuel leaves the tank

[Biker's Nemesis]

Re fitted the wires to the pump correctly? Did you have to take an earth of when you replaced the sub frame?

[rcsyoung]

Heretic said:

Ok, not knowing what year, so I am going to take a guess

some of those had a vacuum operated petcock (fuel valve out of the tank) for safety reasons. If no vacuum to this valve, no fuel leaves the tank

Sorry - it's one of the last of the FI's before the change to the VTEC. I was wondering about the fuel too but can't find where it might have come unplugged from. Maddening.

I'll try and fault find tomorrow night - just didn't have the time tonight.

[Heretic]

Ok, then you are back to no fuel pump noise, meaning no power to the pump... before going to far, check for a blown fuse

[tinker-27]

There is normally a earth point on the subframe from what I remember on a vfr800 FI , m6 bolt , also check side stand wires, think the pipe is a o
Breather should not stop it running ,

[rcsyoung]

Thanks gents. I'll pull it apart tonight and see what I can find.

[madal]

make sure that all the eath wire are on if it will not start ill give ya £50 for it

[rcsyoung]

Got a mobile mechanic in (Julian Cameron - a good guy that I've used before). Took him about an hour to find the fault and about 2 minutes to fix it. The fuel cut relay wiring was faulty. £63 later and it's running and I'm back to work on it tomorrow. Result.

And even better it wasn't something that I'd bodged - just happened to be at the same time as me replacing the rear subframe.

[N Dentressangle]

Interesting - thanks for the update, and glad you got it fixed.

Nice to know we were in the right ballpark!