Motorcycle wont start after sitting for two days?

May as well buy new battery, trickle charge it before installing. Then get out test light and amp/volt meter and Connect them in series with battery cable- if no light, no drain from System short quick test. Help to know what kind of motorcycle- trail model, sports late model, early cruiser-- or just give MAKE, MODEL, YEAR. A few no start cycles taken to shops start right up when handlebar mounted engine stop/run switch's are put into run position. Some street models have a separate fuse in fuse box for ignition/coil/start circuit with a bypass relay for run circuit that has headlight on but no starter button in circuit- hope I got that sentence right, full details would be 3,4 sentences. If this is a newer fuel injected model?? maybe the injectors aren't squirting because side fall safety relay needs reset- this is safety cutoff to stop fuel pumping when crashed, laid on side. If new battery gets it started, check + circuit with voltmeter- less than 14 volts or whatever manual calls for indicates probable alternator failure- cycle will run on battery until discharged, then no start/run until jumped or recharged- some cycles with one burnt diode will give enough current for coil, but not enough to recharge battery. Some cycles use a separate ignition coil circuit direct off alternator and the battery is for lights and starter- I think Honda Silverwing couple and couple others had this- the emergency start circuit worked with dead battery and use of detachable kick starter or push cycle..

If it was the battery, it wouldn't turn over. If it was the "emergency cuttoff" aka kill switch, it wouldn't turn over. When was it last serviced, and what bike is it? Might well be a dodgy plug or even something as simple as needing a tune! MORE DETAILS!

It won't be the battery if you can hear it cranking over. Have you checked that you have gas and put some more in? Try push starting it to get it going too. http://www.motorbikelicense.com/can-you-jump-start-a-motorcycle-with-a-car/

If the starer motor is operating, you have juice. Always check your emergency cutoff switch first, it happens to all of us.

Probably the battery, but hard to tell with this little information.

Not sure how old your bike is... May want to take a look at your spark plugs to, if it is turning over and just not firing.

What model/year of motorcycle? Otherwise its really hard to give good information.

It won't be the battery if you can hear it cranking over. Have you checked that you have gas and put some more in? Try push starting it to get it going too. http://www.motorbikelicense.com/can-you-jump-start-a-motorcycle-with-a-car/

If it was the battery, it wouldn't turn over. If it was the "emergency cuttoff" aka kill switch, it wouldn't turn over. When was it last serviced, and what bike is it? Might well be a dodgy plug or even something as simple as needing a tune! MORE DETAILS!