I've read several won't start posts but my issue seems to be different. I had a new keys made and wanted to verify it would work. I cranked the machine...it started...I immediately cut it off. Inserted the other key and it worked. But the machine sounded like it wanted to start but didn't. I pulled the plug and it was wet. I cleaned it and verified the gap but no start. So I called a couple friends over. We verified it had fire and fuel. Took the injector out to make sure it was spraying correctly...it was. Removed the air filter and checked it...almost new. Oh...machine has 400 miles on it and was dealer serviced at 300. We tried to crank it with no air filter...no luck. BUT...We are getting exhaust out the intake. So...we checked the valves to insure they are closing on the compression stroke. They are and have good clearance. But it acts as if it is firing 180 degrees out. So I replaced the crank position sensor...no luck. Checked the fuses...good. Flipped kill switch several times...no luck. I'm out of options...any ideas.

If the injectors were spraying, then the EFI system is energized and working.

Did you check the timing chain while the valve cover was off? Loose? Skipped tooth?

I assume the EFI light is not blinking.

No flashing lights. Timing chain is good...no broken teeth on the cam gear and the chain has good tension. The fuel pump is running and we have a good spray. We can not verify compression...our compression gauge won't fit the sparkplug hole...too big. And the rubber gauge we have is a POS. But as I said all valves are closed on the compression stroke. We suspect the ECU but don't have any way to check it. Taking it to the dealer tomorrow. Hopefully it is something simple. This has us baffled.

[2015 Z Force 800 53/Trail EPS]

In all this did you try again one of the original keys? And if so, did you try with and without the brake on and in different gear selector positions? Oddly, like doug80638 says, if the injector is pulse- spraying, the efi system is activated.. and you say it has spark..and air, it should run if it has compression and is in time. What's missing? Charge the battery and try again. Maybe it's low enough that the coil charge isn't enough to fire the plug under compression during cranking. Something to try anyway. It's too new to have any real problems...unless you have been riding it in very dusty conditions with the CFM air filter that is.

Have charged the battery...air filter is new...tried starting in different gears. The only thing we can think of is the ECU needs to flashed or replaced. It acts like it has jumped timing but as I said the chain has good tension and the gear is good. Thank you for your suggestions. Hopefully the dealer can figure it out.

Figured out my problem or should I say the tech figured it out. It had jumped time. The timing chain tensioner was bad and the chain was stretched. It had only 423 miles on it at the time it wouldn't rank. They didn't have a tensioner in stock and I was heading to Colorado and Utah the next day to ride there was no time to order a new one. So the tech changed the automatic tensioner to a manual one. It worked...I put a lot of miles on the 500 and had no problems. Now I have to decide to leave it the way it is now or replace the chain and tensioner.

Excellent!

Just need to check chain tension once a year to make sure it is taut.

Old saying: If it ain't broke, don't fix it :-)

[2015 Z Force 800 53/Trail EPS]

I remember the old manual tensioners on my old Hondas. Had to set them once in a while but..they never failed.