I have a 2002 Yamaha YZ250. While riding the bike engine died, could not start it since. Already changed sparkplug, cleaned carburator and airfilter. Does anyone have a solution or know where i can download a free workshop manual? I only find free workshop manuals for the yz 250f.

sounds like a problem i had with my v star if u can charge it and it starts and runs for a bit then dies again check the rectifier which charges the bike

sounds like you need to clean your carbarator out probally dirt down in the bowl. make sure that u clean everything out when you have the carb apart.

Chances are that some trash has gotten into the float bowl and is intermittently plugging up the main jet. When the bike dies the suction on the jet dies, the trash is no longer blocking the jet and the bike starts right up.

It's a carburated bike. You need to have your carburator cleaned. It's not a difficult job, howver if you are not comfortable with what your doing a shop will charge a half hour or 1 hour o clean it for you on average.

Your carborator mixes your fuel and air. when the bike is at idle it is only getting fuel from the "idle" needle. The smallest needle in the carb. These needles are hollow. As fuel sits in the carburator for a long period of time (over 2 weeks) then the fuel can gum up and clog the neeedle. If it runs when the choke is on but dies when you take it off the choke this is what is happening:

On some bikes a "choke" doesn't actually choke it of fuel, sometimes it actually enrichens it. Your bike is probably set up to open another passage way besides the "idle" needle allowing fuel to go into the engine from another passage. you shut the "choke" off and now it only has the idle needle to get fuel from. If that's clogged the bike dies.

A can of carb clean and a screw driver is usually all you need to clean a carb. But if done wrong you will pay more to have a pro fix it.

How good did you clean the carbs? The idle jets usually have small holes along the side, and if they are blocked with dirt or bad fuel, it won't idle. Make sure ALL of the passages are clear, and all jets are clear, through the center and holes in the sides of the pilot jets.

i would start by changing oil ,all filters,sparkplugs....settiing/checking valve lash....change /settting points,condendsor[if it has them instead of electronic]...clean all carburators [drying gas makes a varnish that will plug jets,ect] fresh battery and gas
ride safe and free