250r problems

[honda380]

im a pretty mechanically inclined guy and ive tried everything to make this thing run and it wont. all i did was put new rings in it, put it all back together the correct way and it will run for about 3 minutes and then bogg out and stall. so first thing i did was check the plug and it was soaked so i played with the jets and lowered it from a 180 to a 160 and it did nothing. i also checked the reeds and cleaned the carb out. everything is fine. the plug is always the same wetness, it is never less wet even with the smaller jets. there is one thing i didnt understand though, when i had the 160 main jet in, it was puffing black smoke, not the usual white. anyone know what it could be, ive tried everything i know, which may or may not be a good thing. any help is appreciated, -Corey-

[krt400ex]

if ur plug is that wet, u may be losing water into the cylinder. u might have put the head gasket on wrong by accident. or something else. check the tranny oil. if its milky and light colored or white, the ur def losing water somewhere. the reason it won't run ling is because the plug is fouling out so quickly. u may be having probs with ur ignition system, causing weak spark and not buring all the fuel. that would cause ur plug to get wet and foul out quickly. just some guesses

[plkmonster2]

If your plug is wet, try to light it, outside. it will catch on fire if it is gas. I'd check your pilot jet. Sounds super rich.

[krt400ex]

ya, but how rich could it be if it ran fine with a 180 and now he dropped it down to a 160?

[DezSled]

When you put new rings in it did you happen to notice the condition of the bore? Was it shiney or did it still have the boring/honing cross hatch marking in it?
You reringed it for a reason, did you have a lot of time on that piston/ rings /bore?
Rings need to seat in, and probably could have used a light honing to help them seat. Do a compression check, should be around 150 lbs or better if the rings are doing ok.

[plkmonster2]

If he is just idling, the main isn't doing much. The pilot is more influential.

[Aceman]

Make sure it's not a fuel delivery problem. You need to start eliminating problems one at a time. Make sure you're getting full fuel flow out of your hose. Then start it again with the gas cap off and make sure your tank isn't creating a vacuum. You cleaned the carb, but did you blow through all the passages and make sure the float height was correct when you were finished? Do your needle and seat seal well? Set the float height first then blow through the fuel inlet of the carb while holding the float up, you should not be able to blow any air past the needle. Does your quad start back up immediately after it bogs and dies? A bad coil will sometimes heat up and then lose spark. It will restart and run fine when the coil cools back down. Also, make sure your air filter is clean. You want to make sure you don't have other problems adding to the main problem. Just throwing a few things out there for you to check.