I have a 1985 yamaha yfm 200n moto-4 and it wont idle. It will idle for like 5-10 seconds and then die. I can start it pretty easily and when driving it it runs fine. I have cleaned the carb twice and it didnt really do much. I was thinking a carb kit for it but i was unable to find one of those for it. Any help would be appreciated

 

Put some starter fluid in it every once and a while i had the same problem with one of my old quads, for some reason it worked. put the fluid into the carb

 

If you are sure the pilot jet is clean then open air mix screw until it will idle.I have never used a carb kit in thirty years, a few floats though.

 

If it won't idle, more than likely your pilot jet is gummed it, it has extremely tiny ports in it, very important that its clean,or the passage it threads into is plugged, take out the pilot, make sure all the holes (may have side holes as well as end tip hole) are open, and put the straw from the carb cleaner in the jet hole, and make sure it sprays out into the carb. You can try dumping a can of Sea Foam into the tank, then run it around for a while to get it into the carb, then leave it sit over night to see if it will dissolve the varnish that might be inside the carb ports. If that doesnt work, you will need to pull the carb again and make sure its spotless. dondeere makes a good point, make sure the idle mix screw is set right, a good starting point is 2 turns from lightly seated, then go from there to get it to idle smooth.