Spark plug fouling

[Louis069]

Hi there hope you are all doing well.
I have a 2008 EC300 and been battling the jetting on this bike since i have owned it but think i have finally got it worked out. I have gone from:
-N1EF clip 1, 35 pilot, 175 main
To
-N3EG clip 1, 38 pilot, 175 main
so it is running much, much better and leaner, and im having a blast on it very powerful and tourqey.
I obviously had issues with the spark plug fouling at the start with the richer jetting

However i still havent been able to negate the problem fully, even with the new jetting. For example after spending anthing more than 15 minutes in woods singletrack and then exiting the woods onto a fire road and go to open the taps it will stutter/choke up before its gets to the powerband so i come off the throttle then on again and i will do this about 3-4 times before it clears itself out and will rev cleanly again.
Then this afternoon when i started it up, it went for about 5 seconds and before i could get the choke off it cut out. This is a photo of the plug after i took it out. Ended up putting a new one in and went 1st kick

I dont think it is running rich as the jetting seems to be on the leaner side. So all i can think of is reeds? spark plug cap? ignition coil?
I am running a BR7ES at the moment, as recomended by a former dealer in the area(linton at das, christchurch), he runs the hotter plug as he says that it is better suited for low rpm conditions. Not only that, thats what beta and ktm all use. He also says the BRP7ES with the projected tip can work better in some situations your thoughts? Im probably going to give it a go to see anyway.

Im running castrol power 1 2t at 50:1
Also forgot to mention it has had a new piston and rings about 10-15 hours ago.
Oh and i can still only get about 70km to a tank which is still double from what i used to get but not as good as some of you are getting.

Thanks very much for any advice you may have