I have a 1986 TRX 250r with a DG pipe and silencer, K&N air filter and cover, stock air box and lid.i have no idea what has been done to the engine beyond that. Silencer has been repacked, air filter cleaned, PJ carb rebuilt and cleaned including new choke assembly and float valve. New throttle cable, fresh 92 octane gas with Belray at 32:1, I have a Champion NC3 plug. The quad has 175 pounds of compression, 48 pilot, 155 main, stock need on the third clip. I am at about 988' elevation and it is about 30 degrees in my garage. I cannot get it to idle. As soon as I let off the throttle it drops off and dies. Air screw adiustments and turning the idle knob make no difference. Also all carb vent lines have been replaced. Any advice is appreciated.