2019 KLX250S, bought this a couple months ago as and upgrade from my 2012 Yamaha XT250. So I have been working my way around the forum, gaining knowledge and doing a few mods.
I removeld the lid to the airbox, which made a noticeable improvement in performance, just added the 13 tooth CS sprocket, so far I like it. I can't believe how tight the sprocket nut was on,
used a 1/2" breaker bar with a pipe on it. Jammed a wrench through the rear wheel rotor slot, but gave up because I was afraid I'd break something. Got the oxyacetylene torch out and heated the nut for removal. It is not going back on that tight. Back to the front wheel. I have been dealing with the front brake, warped or bent rotor, caliper with frozen, brake pad locating pin. On the 3 yr old bike???
Got that straightened out, without buying new caliper or rotor, but the braking doesn't seem to be as firm as I think it should be. I can't do "stoppies". I have tried repeated attempts to bleed the system, unconvinced I got it all, mainly because the hand control travel, and unlike some other bikes there is no adjustment at the hand control. So I have the caliper off, but in spinning the wheel, it only does a turn or 2, seems like some drag. I loosened up the front axle nut, torque I believe is 65 ft/lbs, and the wheel spins freely. Hmm beginning to believe that the spacer in the hub between the two wheel bearings might be a bit short, and when the axle nut is tightened it puts a side load on the wheel bearings. I'm going to try and reseat the bearings possibly not pressed in tight enough. I suppose I could go in and shim the spacer a bit as well. Maybe machine off a bit of material on the back side of the hub where bearing is seated? Anyway I am going to scuff up the existing brake pads which have plenty of material, and sand up the rotor a bit, to see if it might not be air in the hydraulics afterall. Appreicate any thoughts you might have>

 

My front brake leve/travel/feel suck. Everything is good and right but still the problem persists. I checked a new model at teh local dealer and the brakes feel normal, so I must have something up in the master/piston/seal going on.

It sounds like you have this in hand. Hydraulics. Mechanical. Not a lot of choices. Be sure the check the caliper pistons for cleanliness and smoothness of operation, and the rotor for any dishing.

 

I once had some wheel work on mine done and the #1 mech sent it back to have something machined off the brake system, they may have an error in a spacer or something.