1986 Honda XR250R Blows Black smoke

Hi i am new here i got an 1986 Xr 250 it got two new valves new piston rings and gaskets new spark plug and new fuel. she starts up one two kicks but puffs black smoke she running rich right? i took the air filter out and it helped cheaked the carb float level it all good. it burns gas like crazy with the air filter and no power in about 3 miles it emptied the tank 2 1/2 gal. with out air filter got power not as much as it should tho and a lot better on gas. the carb is like new in side and i cleaned it just to make sure nothing was blocked but still i don't need the coke to start and the choke is not sticking i even tried turning the pilot screw leaner it didnt help at all. the jets in the carb are 125 and 40 i think they are stock jets. could the jets be wore. i need some help i don't want to run without the air filter i need some help please?!!

in about 3 miles it emptied the tank 2 1/2 gal.

I don't see that possible. You've got to be losing/leaking gas some other way.

Hi... yes black smoke means too much fuel (rich). Not needing any choke for cold start is usually a sign something is wrong. I agree with TrailRyder, using 2.5 gallons in 3 miles, the engine would not run with that much fuel dumping in. Check for fuel leaks everywhere (tank crack, overflow tube pissing, etc). Otherwise clean the air filter or get a good aftermarket filter like UNI, do not over-oil the filter. That's great the carb looks so good inside... If you don't already have one, get a manual and follow the float adjustment procedure carefully (I know you checked it already). Having a manual will also help you to notice if any parts are missing from the carb diagram, which I suppose could happen if someone's been working on it. But even a correctly adjusted float will not cure a leaky needle valve/seat, so take a good look at those too. Fuel jets usually do not wear out but they will often get crap/gunk inside and get smaller orifices, which causes a lean or even no-start condition, but you don't have that problem so I wouldn't worry about the jets except to give them a quick check and make sure they are snug. Not sure what else... hope this helps, good luck and keep us posted on what happens.

pull the carb apart and make sure that the jets didnt vibrate out. had that happen one time on a buddies quad

thanks the bike got no leaks at all in the fuel system once i lowered the float to just a little trickle in the carb it started with the choke ran with out it but at idle it blew black smoke pull the throttle it revved and didnt come back down and no black smoke i turned the ide screw down didnt change it then it just stalled started it again blew black smoke then the same thing so i shut it off. so i took it apart and reset the float and cheaked the needle vavle by blowing down the gas line which is new with clamps on each end the and if i had an gas leak i would know it wounld be on the engine there no hoses leading the over flow away from the engine. i didnt have the manuel for this bike but i have an xl 500 manuel and the carb tear down looks to be the same. now i have the pilot screw 1 3/4 turns out according to that book. i have a new air filter but even with it in it runs better with out. what else to say? hmm start bike very very little black smoke can see best wen reviv from a stop first gear lots of power hit second gear good till half way then black smoke and bogs and seems to misfire. pull clutch and revev twice then back to accel perfect but still little black smoke til near end of gear then the same for the rest(at end of gear fine after the reviv in the middle. the reviv in the middle is to clear. the spar plug is black exhaust at end of the silencer like soot. i am stumped i was thinking maybe a bad float maybe how would i cheak it a like plastic rubber one and had the carb off no loose jets none clogged and pilot screw open(not blocked)the very first time i took the car apart to cheak the inside the little plastic cone like peice was up side down i fliped it back over what would that do if anything?and the needle on the throttle is in stalk position. and again there no mods to the bike what so ever just a blowen donut gasket in between the header pipe and muffler. but would that make it run leaner i have got no idea what else to cheak

i still can't belive that little 250 ate 2 1/2 gals of gas in 3 miles and it blew black smoke every second of the way i ended up walking it back after it backfire like a shotgun twice and died out

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