Have a starting problem with a 2017 CFMoto 520S EPS which I cannot work out.  Quad has only done 96klm (in Australia).  It does not prime before starting and will not start. Normally, the fuel pump will go for 5 seconds after you push the yellow start button, but just recently it has not been priming and will not start when you press the green button.  I have removed the cover to expose the fuel pump.  What I do to get it to start is directly connect 12V to the fuel pump, the pump whirs and then it will start.  Thereafter, it will start normally without the 12V connected directly to the pump, that is, you will hear it priming for 5 seconds after pressing the yellow button and then it will start when you press the green.

But if I leave the quad for a day or so, it will not start normally, but you have to connect up 12V directly to the pump.  I thought the pump was at fault, but not sure now.  I think some electrical fault which prevents it going through the normal cycle of priming before starting.  Funny thing is, when you force the pump to prime it thereafter seems to remember what it is supposed to do, but if you leave it long enough it 'forgets'?  What electrical component controls that priming sequence? The relay?  I have checked it and seems ok.  Fuse ok too.  Just replaced the battery.

Any help greatly appreciated.

The fuel gauge has not worked properly for some time.  It works and shows the correct fuel level when you first turn the machine on, but after you take off the level will fall to zero.  Some ground problem?  Never got to the bottom of that, but does not stop me using the bike.

Looks like it is the fuel pump.  When you leave it 24 hours it is sluggish turning even though it is receiving 12V but then picks up speed.  And, apparently, the longer it is left the worse it is.  Replace the pump?  No other fix?  Could it perhaps just needs cleaning out?

[2015 Z Force 800 53/Trail EPS]

Probably have to replace it if there is no other cause for the way it acts but no harm in taking a look...

You initial description implies an electrical issue. If you can spin the motor with direct 12V contact but not through the ignition system, then something is amiss. I'm left wondering about bad connections either positive or ground.

Is there 12V present from the ignition when the pump won't turn?

Do you supply a separate ground when you "jump" the pump?