Jetting: kx250

Background: 2003 kx250, stock jetting, 4500 ft elevation, fmf gnarly pipe, v-force reeds, stock everything else.

I got the bike a couple months ago. It seemed to run okay, but lacked bottom to mid range, so I lowered the needle one position. It improved slightly, but the bike still has a weak mid range. I have only ridden three times since I've had the bike, and temperatures were in the 70's for the first two rides. Last ride it fouled a plug within a few minutes of startup. I put a new plug in and it ran fine. temps were mid 80's. I bought a few sizes of main jets as well as pilot jets to mess with it some more. I haven't touched the main yet (165), but I replaced the 50 pilot with a 45. went riding yesterday and fouled a plug within 5 seconds of idle. I put a new plug in and fouled it in about 30 seconds. I then gave up and loaded the bike. Plug was absolutely drenched and black. I thought reducing the pilot would solve my issues. Where is my problem?

I have never jetted a bike before, so I'm unsure of what to do next. I noticed oil coming out of the front of the cylinder. The pipe isn't sealing well. Would that cause an issue?

Thanks.