I'm taking off the FMF Apex muffler and putting the stock furnace back on to see if there is a difference...who knows - stranger things have happened...maybe a lack of back pressure is creating a lean mixture and fouling things once it runs for a bit.
2012 KTM 990 Adv-R
2014 Superduke 1290R on its way
And how can this be? For he is the Kwisatz Haderach!