General things to look for if your bike won't start

There are only 3 major systems on any internal combustion engine. Mechanical (pistons going up and down, valves opening and closing): It's REALLY obvious when something fails in this group. Electrical (battery, CDI/black box, coils, plugs): This system is fairly reliable any more, but things Can just fail. Moisture is an annoyance (including high humidity; sometimes vehicles will shut down in high humidity, due to electrical issues.) If it's been rather humid, waiting a day or two to see if things dry up a little might help. And the final system is the air/fuel. This is the most common place for things to go wrong. Water (again) can easily find its way into a gas tank and then the float bowls (the part of the carbs that holds the fuel that's just about to be burned).

That said, the 2 things (in order) to check for are water in the float bowls and that the spark plugs are generating spark. These are Extremely simple tasks to do, and a Great introduction to working on your own bike (if you have even the slightest desire to do so). Water in the fuel is nearly the ONLY thing that will cause the bike to work fine one day, and suddenly not work the next. (You may have, for instance, filled up with a bad tank right before going home, and had cups of water go straight into the carbs). If you Don't want to do your own work, then try making sure all the integrated safety switches are tripped (meaning the kickstand is up, bike is in neutral and clutch lever is pulled in).

If those things are done and you still don't get any cranking, then buy/borrow/steal a multimeter and check the battery voltage... then with the meter still hooked up, try to start the bike ~ if voltage reads 12.xxx VDC and drops to below 10VDC, you need a new battery.

If the bike IS cranking over, and it hasn't run in awhile, clean the carbs (or have someone else do it), check/replace the spark plugs, and check/adjust the valves. Your bike won't start/run without one or all of these things being done.

Note: If you have recently swapped any of the items from a pre-F9 (1994) to an F9-or-later bike, you must do additional electrical work for the spark plugs to fire at the right time, or replace the components as a unit:

• Alternator Cover (Left Engine Side Cover)
• IC Igniter (CDI, Blackbox)
• Wiring harness

Also, if you have performed modifications (such as hot-wiring or transplanting to a go-kart) to an ignition system from an F9-or-later bike, you have to take into account the anti-theft resistor, which is normally attached to the grey wire inside the ignition switch.

These two points are mentioned here because their symptoms exactly match a bike which will not start for "normal" reasons -- the engine will turn over, but it will not catch.