welcome to the forums..first off..these machines are designed to shut down when they get too hot..if the fan doesn't come on..the fan control sensor tells the c.d.i to shut if off..to keep the motor from seizing..it's a saftey feature they put into these bikes..put your carb jets back like they were ( stock )..and check the oil temp sensor..your fan control sensor..and the fan itself..if anyone of these is not working..your bike won't run...well..it will run.it just wont run long..not until you get the oil to cool from the oil cooler...which gets cooled by the fan...you really have to get these bikes hot..and not just by idleing..start with your oil temp sensor..bottom right..near the foot peg..behind a metal cover..more than likely...you will have to remove it to test it..do you have a service manaul for this bike ?..if not..you will need one..the pic in my post..is a 89 trx350d foreman i restored..i've owned two of these..one was a 87..i'm pretty smart on them..lol.new to the board. just got a 87 350 4x4. rebuilt top end. will start when cold but i rode it for 20 minutes and it wouldnt idle and died. would not start back up until it cooled down. fuel pump pumps. carb clean. stepped up on the pilot jet from stock 35 to a 38 then 52 when 38 didnt help. my idle screw is all the way in on the carb and i have to use the cable to adjust idle. when i warm it up the idle slowly falls then dies!!! when trying to start when warm if i give a little gas it wants to fire if i hold wot it wont even try to start. any ideas? sorry so long just want to give all info possible, im usually good diagnosing problems but this has got the best of me.