I know there's a ton of info out there and I've been doing lots of research. I just need figure out why it's cutting out right in the last rpm's of the powerband right before I shift up. I'm just an average rider that likes trails and wide open areas. I bought this used 2002 Kawasaki KX 250 with a Pro Circuit Platinum chamber and had the stock silencer installed. I just took the silencer off and the tube inside the silencer was broke off with burnt up packing. I have a new Pro Circuit 304 Factory silencer on the way.. The carb is cleaned and has stock jetting #165 and a #55 pilot and stock needle at in #2 position from top. The air/mix screw is opened at 2 turns. The bike is very responsive and doesn't backfire. The only problem is right before I change gears it sounds like its not getting enough fuel or spark to pull thru. My spark plug color is good with a nice golden tan look to it. I'm using a NGK Iridium BR8IEX. I drained old gas and put fresh 40:1 Amsoil Dominator / 93% octane gas mix.. Its an injector oil that is formulated to mix 50:1 to any spec. I just like the added oil for lube. I use this mix in all my 2 stroke for years without any issues. I cleaned all grounds to bare metal with dremel and used electrical grease on all connection including plugs. Here's where I'm puzzled.. I did a compression text and factory is 171 lbs. I use a Motion Pro compression gauge. With a cold engine and the throttle wide open I'm getting 215 lbs of compression. I can only assume there been some kind of boring or head work. Here's what I'm thinking: When the new silencer comes, I'll install it and test it out. If that doesn't work I'll go up to the next jet #168. Does anyone think I should try racing fuel..? What would you do if you had this problem..? THX..