No spark and Im stumped

I bought a non-running 2009 wr250r a couple months ago. The previous owner had the head rebuilt (new cams, valves, cam gears) because it had been ruined by a manual tensioner that was wrecked way too tight and stretched the chain. He fixed it and rode it for 3 hours and said it started to run worse and worse and then died. Anyway, I have replaced the head (cam seats and cam cap was completely scratched and destroyed, the cams couldn't spin) and i replaced the cam chain with was several mm longer than the replacement. I have put the bike all back together and it won't start. Starter turns but there is no spark. I have checked the kickstand switch, it ohms out and functions properly. I have checked the lean angle sensor, it has proper voltages in all angles. I have checked the ignition coil, it is good, I have checked the crank shaft position sensor, it has proper ohms. But when i remove the spark plug and ground it to the cylinder there is no spark. I have the service manual and so all of this has been done by the factory specs. I have double checked all wiring connections and found nothing abnormal. There are no check engine lights and never were as far as I can tell. I have not run diagnostics because there is no check engine light. I have also unplugged the ECU overnight to reset it. What am i missing? All of the starting attempts has been done with the bike leaning on the kickstand, in neutral. The starter turns strong (I've made sure I've got 12+ volts) but no spark. The only thing abnormal is the coolant temp light is on, but i am assuming it is on because the coolant has not run through the motor completely and so the sensor is dry (or because it just stays on until the bike is running maybe?)

Any and all input is very much welcome, I'm totally stumped. thanks in advance, i can't wait to ride this sweet bike!!

I'm assuming when you checked the wiring you checked the any associated fuses, diodes, n relays? Have you checked the stop switch on the handlebars? I don't remember if the engine will turn over with that off or not. Not tryin to be a dick n suggest stupid things... The end of no spark troubleshooting is to replace the ecu n that sounds pricey... Do you know of anyone locally that has a wr so u can swap out for a minute? The coolant temp sensor shouldn't stop the bike from starting or driving...

Also probably wouldn't cause no spark, but your timing gear on the crank might be fairly cooked now too. In the one rebuild video I was watchin dudes was worn down decently... Not sure of mileage or anything on that bike tho...

Not sure if the crank is worn down, i see how that could be possible, but with the new chain all the timing marks lined up perfectly. With the old, stretched one the exhaust cam was off about half a tooth.

Not offended by your fuses and diodes question. I have checked all fuses. I'm not sure if there is an applicable relay, there is a starter relay, but the starter is working so I'm good there. What is a diode? maybe i need to double check the wiring diagrams. I appreciate the help. I do have a friend who has a riding buddy with a wr250r...ill see if he's up for me borrowing his ecu. Thanks! All comments and questions are very helpful and welcome, I'm at my end with this thing. I just can't figure it out!!!

The diode is part of a relay. It's part of the ignition troubleshooting... I haven't had to troubleshoot a no start but when these posts come up I like to look into possible problems so if I do have to I have a better knowledge base... Plug is gapped correctly? Have you tried a new one just for shits? I have heard of insulation breakin, or being defective n causing an unseen short so there is no spark but everything looks good... That kinda did just happen to me in a vape rda. the insulation got toasted n it was jumpin there instead of sending juice thro my coil.

Buggered ignition coil?

He did say that checked out as good. Not that that's always 100%. Some parts can check good n still be bad... The best bet might be swappin parts with a runnin one. Than buyin the part that fixed it...

yeah, the coil did check out ok, but if parts can test ok and be bad then I could be in a world of trouble! I do have a friend of a friend with a WRR so ill feel that out and see if he'd be willing to let me yank the relay and ecu from his... Whats odd is that the guy i bought it from had fixed some mechanical issues (timing chain tensioner and rebuilt head) and had rode it a few miles and then said it started running worse and worse and died. then he had to push it out a forest service road. This story seems to make sense because he gave me a box full of parts (valves, springs, cams) and the bike. When i took the top end apart the head was completely shot. so i installed a new one. I suppose some random electrical issue could have popped up while the bike was sitting in a storage unit but it seems so unlikely...? I've triple checked all wiring for damage and loose connections. I've double checked all sensors so electrically speaking I'm down to the diode/relay and the ecu. I'm calling my local yamaha dealer today to see if they have the relay...i tried testing it but the pins are so small its nearly impossible to connect power and a tester to it without touching another pin. I'm also going to see if the stator recall has been done on it. If anyone has any other suggestions please keep them coming, not having a bike is no fun at all! Thanks guys for your input.

At this point the stator is your best bet imo. Or at least the pickup sensor attached to it. As far as I know sensors aren't a known trouble spot for these bikes(I've managed to fry several stators, but not the spark triggers), but it's worth checking it out.

Any luck yet?