2002 Honda 300ex Stalling out

Ok, 2002 300ex, starts up great, after 20 min or so, stalls out while riding. Does not start
up right away, sits for 2or 3 min, starts up no issue, dies out again 5- 10 min later, issue keeps repeating. HELP......

I would say you have a problem in your ignition system, something is failing when it starts to get hot. Most likely culprit is the CDI, but I would find the specs and procedures for the direct resistance tests and check everything else after you get it warmed up and it stops running. If you don't have a repair manual, get one, it will have the specs and procedures for the ignition tests and a troubleshooting guide to help you track down the problem. The Clymer manual is cheaper and decent, but the Honda factory manual is better IMO and worth the extra money if you ask me.

CLYMER HONDA TRX250X TRX300EX SERVICE REPAIR MANUAL: eBay Motors (item 230459750016 end time Aug-06-10 10:58:27 PDT)

Honda TRX300EX TRX 300EX 300 EX Shop Service Manual OEM: eBay Motors (item 190422503894 end time Aug-22-10 10:18:37 PDT)

Thanks, one thing I forgot to mention, if I leave it idle , and I have for at least for a half hour, its fine, I would assume its pleanty hot by then.

So you are saying that if you let it warm at an idle for 30 minutes, it's ok? Does that mean you can ride it without issue if you let it warm up that long? Or are you saying that it doesn't exhibit the problem if all you do is let it idle?

Ride the machine until it shuts off, pull the plug out, and with it connected to the boot and grounded to the outside of the motor, turn the machine over and check for spark. This will tell you if the problem is related to an ignition issue or if it is something else. I would still think the ignition is the most likely problem.

Well I finally had time to check it out and it will idle forever without shutting down. Any other suggestions/ Tx

I will say this again, ride it until it shuts down, take the plug out, ground it against the motor and turn the bike over to check for spark. If there is no spark, obviously you have an ignition problem, if that is the case, I would still say that the CDI is the most likely culprit. Again, there are some tests you can do to check the other components. I posted some links for repair manuals in a previous post, on top of having test specs and procedures for your ignition components, they will have a troubleshooting guide that may help you track down the problem. If there is still spark after the machine stops running, then your problem is probably and interruprion in the fuel flow. That could mean debris in the fuel tank or carb, a stuck float or a fuel tank that is not ventilating properly.

Sounds like the needle & seat are gummed up. Clean the carb. with 2+2 carb cleaner. That will dissolve all varnish and gum.