Pilot jet dirty?

Check the starter jet in the bottom of the float bowl is clear .

Evening Simon.

I might have misunderstood some of the posts here, but the jet in the float bowl that Swoop is referring to is not the pilot jet, it is for the choke. I've cleared some of mine out with carb cleaner and 0.4mm copper wire.

You say started on full throttle, which has me thinking maybe it was flooded up in the first place. Doesn't account for dry plug though.

It could just be "one of those things". I've had bikes occasionally not want to start and then once they do they are fine after that. Never do figure out what the problem was... usually happens after sitting a few days.

And if plug is actually wet with fuel, it's likely flooded.

I use a spray bottle filled with premix and spray in the carb body while kicking to try to determine if it’s a carb issue or something else. I’m not sure if a popped crank seal would remove the vacuum to the point that fuel would not pull from the carb. I’ll let the experts answer that question. 

That hole you see above the pilot jet is where fuel is delivered to the engine after passing through pilot jet. www.xr650r.co.uk/misc/IMG_6377.JPG

The air comes in from bell end of carb... your model has a brass bb in the actual passage... but that hole with bb is connected to the center hole at rear of carb. (hole to right is blanked and goes nowhere) www.xr650r.co.uk/misc/IMG_6375.JPG

Air from rear of carb is regulated by air screw and then goes forward where it mixes with fuel in a void at the pilot jet... brass bb by pilot jet is that passage. www.xr650r.co.uk/misc/IMG_6377.JPG

Hope that helps.

C would go somewhere if air screw was on that side of carb.

B's main purpose is to supply air to needle jet (emulsion tube) that slide needle fits into. But on some models they tee B into A.

If you remove air screw and spray in some carb cleaner it should come out B and the pilot jet well.

High pressure air into air screw hole should also be able to be noticed at pilot jet well.

I have removed the brass bb in A on carbs that are really crudded up... like with foam from a rotted air filter or debris from an animal nest that can plug A and B. Usually not needed. I didn't replace the bb and while I'm sure that defeats some kind of carb calibration magic, didn't seem to affect running. I don't recommend removing bb in carb intake bell except as last resort. And note that other passage bb's such as the one near the pilot jet should never be removed and if they are missing must be replaced.

to get mine to start, i need to lean it almost to the ground for a few seconds then it starts in 3 or 4 kicks. I can kick it for 3 years, but without the lean, it wont ever start.

Not sure but possibly an issue with the reed value?