Need Help With Atc 250sx

[will1806]

i recently got a 85 honda 250sx. it was running about a month ago but the previous owner told me that the last time he rode it killed like it had ran out of gas. now i am trying to get it running (though not succesful). i have change the gas, changed the plug, torn down the carb and cleaned it. all i can get out of it is a little sputter and nothing much else. i now this isn't much information but any help would be greatly appreciated.

[mad_max]

Does it turn over easily?

Have you done a compression check?

[will1806]

yes it turns over easly but it also has good compression no i dont have compression check but it easly blows my thumb off spark plug hole

[whipit]

it probably has nbo spark if it just all the sudden died like that. something electrical

[will1806]

it has spark, can i check voltage with multimeter. it wont run for more than a second or two

[will1806]

i have a brand new plug in it and it has no more than 20 seconds on it and i can already see black soot on the plug

[mark38090]

I had a similar problem with mine and it turned out to be the coil. Have you checked the specs on the coil with your meter. If you don' t have a manual, do a search and you can download one here, thanks to Howdy. Let me know.

[Dirtcrasher]

Did you take out every single jet and clean it thoroughly?? If it sat awhile, those jets must come out and get soaked in carb cleaner...

[Huffa]

Take the air filter off and spray a small amount of carb cleaner through the opening while holding the throttle open. Now try and start it. If it starts right up, for a few seconds that is, you know it is a fuel delivery problem.

[Huffa]

it has spark, can i check voltage with multimeter. it wont run for more than a second or two

After it dies, does it start right up again for a second or two? Did you check your fuel flow at petcock. Did you take apart the petcock and inspect filter in tank and petcock bowl?

[chrisorbics]

Hi my 1985 250sx had a bad gas cap. It would not vent so no gas could flow. Also the tank is rusty. Try taking off the gas cap but first shut off the gas and take off the little bowl on the petcock. There is probably a lot of crap in there. Clean it out real good and before you put it back on turn the gas on and let some out to clear some rust out. Now put the bowl back on. I would get a clear gas line so you can see if the gas is flowing through or not. I would also get a fuel filter so you do not have any future problems. If the problem is your gas cap just drill a very small hole using the original vent hole as a guide.

[will1806]

the tank i have is plastic. i tried the carb cleaner thing and it would run for a second are two. i have cleaned the main jet on the carb. everytime i try to adjust the pilot screw it does the same thing. nothing are it may sputter for a second are two. i have a car off an 85 trx 250 that i have sitting i carb cleaner overnite. i think the one off the trx is in better shape then the one of the atc. oh yea will the one off the trx work on the atc? it should. shouldn't it?

[team-red-rider]

yep should work fine!

[will1806]

it kind of sucks i have worked on a few bikes in the last few years and never had one do me this. i fixed a 110, 125, 200, and a shadow 500. normaly for those all i did was clean the carb and tank do a little adjusting and it started up fine. except the 125 chunked a gear out of the low-high switch box. that was fun to fix.

[Tri-ZNate]

ok first thing first.
1. The plug has a blue spark right?
2. try puttin a few dribblets of gas in the plug hole and then fire it. Does it start easier/at all?
3. Are all your grounds connected firmly. there are several under the headlight and one or two on the frame.
4. One thing that will keep it from starting (But I dont think it will make it cut out on a ride) is the neutral and reverse plugs down by your right foot peg. They are on the engine and usually have a metal cover over the boot that folds back. Make sure they are on. or if you turn the key the neurtral light should come on.

The "it killed like it had ran out of gas" sounds more like a plugged jet but check the grounds too.

[Huffa]

the tank i have is plastic. i tried the carb cleaner thing and it would run for a second are two. i have cleaned the main jet on the carb. everytime i try to adjust the pilot screw it does the same thing. nothing are it may sputter for a second are two. i have a car off an 85 trx 250 that i have sitting i carb cleaner overnite. i think the one off the trx is in better shape then the one of the atc. oh yea will the one off the trx work on the atc? it should. shouldn't it?

It's got to be your pilot clogged or the float needle is not letting fuel flow into the carb from bowl then.

[will1806]

i cleaned the jets maybe i missed something. after the trx carb finishes soaking i will clean it off put it together and try it. it looks the trx carb looks in better shape than the atc carb just a little rust no gum that that i could find, it just spent time outside in south louisiana (outside unprotected). the plug is brand new the neurtal ligth is on. and has blue spark. i rode this bike maybe around oct or nov. of last year

[will1806]

the guy who supposedly rebuilt the carb never thougt to put the pilot screw back in the carb so it has the pilot screw of the trx carb. (used 22 yo part swapping you got to love it) sometime the only/cheapest way.

[will1806]

i have one more piece of info. i think the starter solenoid burnt. plus i havent bougt a battery yet so i have been bypassing the solenoid. i have done this many times with no problem so i dont think this is the problem

[Huffa]

i cleaned the jets maybe i missed something. after the trx carb finishes soaking i will clean it off put it together and try it. it looks the trx carb looks in better shape than the atc carb just a little rust no gum that that i could find, it just spent time outside in south louisiana (outside unprotected). the plug is brand new the neurtal ligth is on. and has blue spark. i rode this bike maybe around oct or nov. of last year

Those jet holes are SOOOOOOO small!! Did you hold them up to a light and see if you can look through them? I had lots of pilots in my days that were definitly clogged. Used a small wire to unclogg them but that does not always work and it is not recommended you use that procedure because of scratching the hole, I did it anyway and it worked fine.

The best carb solution is in a gallon container that has a small lowering tray in it. Cost about 12-15 bucks at most auto stores. Carb spray is absolutely no comparison.

[will1806]

yea i no what your talking about. tommorrow i will probably take the best of both carbs then checking all the little holes. reassemble it an try again.

[voodoo1215]

check your float level... I'd put my money on either the float not properly adjusted, or the jets....

[will1806]

it has to be the carb i have good spark,compression, but i dont think fuel is getting to the engine.

[Dirtcrasher]

http://www.3wheelerworldforums.com/showthread.php?t=23819&highlight=carb+cleaning

This is how I feel a carb should be cleaned...