When I bought the bike in January it had a Jardine slash cut, stock airbox, stock jets and ran well. I have recently put on a k&n cone filter, rejetted the carb to a 55 pilot and 155 main as I had read somewhere on here that with the couple mods and jardine exhaust, that was a good combo. Recently I was riding the bike to work and it started puttering out and stalled at a light. I couldn't get it started and knew I had enough gas. Later after work I was able to start it in pri and rode it home on reserve setting after figuring out it didnt want to continue to run in the "ON" position. Bad petcock right? I replaced it with a Raptor thinking this would solve that problem but the bike seems to have been running worse ever since this issue. I know the carb is clean because I had it apart but I'm wondering if I need to downsize the jet(s) and or could this issue lie elsewhere? I'm not very mechanically educated and have been learning and wrenching as I go thanks to you all but I'm reaching out because I DO NOT trust mechanics AT ALL and feel I've hit a wall in this situation. I am able to start the bike and it seems to be idling well but just today I took it out and when I rolled on the throttle it  felt like it wouldnt go further and would lose power/wouldn't accelerate further, just in first. I wouldnt shift because it wasnt hitting high enough. It then stalled on me after a little while. When I started it again after parking it I rolled the throttle and it felt the same, no power and wanting to cut out around a 1/4 turn. I'm hoping it's something simple I am overlooking (don't we all), or one of the typical issues on these thumpers, but regardless..........HELP! Much thanks for reading and any responses ahead.

-J

I was having the same problem after the raptor change and I went in and removed the white washer and replaced it with a thinner one. Got the mid range back, also when I before I removed the spacer I noticed the needle was sticking, so after I removed the needle I cleaned it off before removing the washer and replacing it, now it runs good in the mid-range too.
Of course i'm a newb and don't know much either... just relaying my experiance with the mid-range lugging.

I have a small cone style filter on the breather tube. Everything was working great and strong after all the mods (maybe a little rich) but strong and then all down hill slowly. I've just put the petock on brand new so I cant see an issue with that and I do have the vac hose sealed off from the right side of the carb so it should be running direct to the carb. My plan is to take the carb apart again, make sure all is well, and downsize the main jet by one to produce a slightly more lean mixture. I also need to get into the camshaft and check that out since the cam chain tensioner is a common issue on these bikes.