Just joined on the recommendation of another from a UK site. Currently trying to solve an issue with my V650 turning over but not starting (following a period of exposure to rain whilst stood outside) . Have replaced the Vehicle Down Sensor and moving on to other possibilities. Pretty annoyed as I've never had technical issues with a bike in the rain ever, (9th bike in 40 years).
I have several threads on this,it is much easier just to post it here. Some problems are ambient or temperature sensitive, like bike starts and runs but once hot and stopped it won't start. Spending $$$$v and hours trouble shooting can be averted by doing the following in the order I posted them, more so 2015 Versys 650 ABS and newer;
#1 clean the ECU grounds found hidden below the seat/ gas tank bracket, use scotch brite pad and dielectric grease ( FYI dielectric grease isn't magic, putting it on a corroded connection will = the same poor connection, both surfaces need to be clean, a very small amount is all that is required, too much and it becomes a insulator)
#2 clean all frame ground connections, the ones up front are a problem as the headlight and meter ( display depends on them, part of some displays are the 5 VDC power source)
#3 engine ground, harder to get at on 2015 & newer because of ABS, this ground is prone to corrosion on all model years, it is a PITA to get at and you need to remove the bolt to clean the connection. A tip for those doing this on a 2015 and own diagonal side cutters, the engine ground is a ring terminal, all wiring on MK-3 are short everywhere, trying to start the bolt back into the aluminum casting while trying to relive tension from the engine ground from the battery usually results in cross threading. A simple fix is to cut roughly the same or slightly less width of the thread, in the shape of a V , I have reduced the outside diameter of the ring terminal using channel lock pliers by 0.015 of a inch, what happens is get the bolt started with your fingers, once two or 3 threads push the ground terminal onto the bolt it acts very similar to a fork terminal, however if you followed what I just said, it will stay in place, now you can tighten it down.
#4 the #3 applies to MK-1 & MK-2 as well.
#5 check the 5 VDC , the vehicle down sensor is a good location, the sub throttle sensor or the speed sensor also good but not without using a optional harness.
#6 anytime you have the gas tank off, mark with tape or other means left and right stick coli connectors, pull the stick coils and use a good dielectric grease on the upper boot and also on the inside of the boot that travels over the plug, caution, never use a abrasive such as scotch brite pads in any motion but circular, going from top to bottom will leave small scratches that moisture then carbon tracking can follow, same with the grease, never apply from top to bottom, the spark plug boot area use a very small amount, this allows the boot to slide over the plug then acts as a moisture barrier once in place.