completely lost!?!?!?!?!

[atb400ex]

so im just getting done rebuilding my engine and im totally lost. i started it yesterday for the first time and it idled fine for about 5 minnutes then it died. so im 99% sure its the carburetor because i sprayed some gas directly into the engine and it started up just fine. but ive cleaned and re-cleaned the carb twice now and it still doesnt seem to want to start. maybe im not cleaning the carb properly? maybe theres something else im not thinking of?

any input would be great.

[aDviSol2y]

I know this might be a really dumb question, but is you gas on? Don't worry I won't laugh if its not, I have done this myself.

[atb400ex]

haha not dumb at all ive done it before! but no i made sure it was on this time.

[wgw11]

this happened to me when i was putting my yfz back together this year... how long did you have it apart? cause all i had to do was drain the carb then drain the gas tank then put new gas in and it was fine.. make sure there is no dirt by or around the jets.

[aDviSol2y]

Is the fuel getting to the carb? Since it started then idled for 5 minutes, it sounds like it ran out of fuel. I would say its a fuel issue. Maybe your fuel filter in your tank is clogged. Try taking your intake boot off the carb, push in the throttle and look inside the carb. Do you see fuel squirting in the carb?

[atb400ex]

@wgw11
it was probably sitting for about six months. ill try to get some new gas in it today and see if that helps.

@aDviSol2y
i tried what you said and i didnt see any fuel squirting into the carb? i dont think its anything in the tank either because i didnt go through the tank, i just put the gas right in the fuel line.

[aDviSol2y]

Pretty sure you should see fuel squirting into the carb. I think your jets are clogged.

[atb400ex]

well i soaked all the jetts in cleaner last night so i really dont think thats it.

[slightlybent47]

Did you check the little fuel screen that is supposed to be in the fuel inlet tube?
Check the float in the carb, sounds like the bole is going dry and then it runs out of fuel.
When you get it running don’t just let it idle, ride it some and see what happens. It may have a small piece of debris and by riding it, it may flush it through.

[atb400ex]

i didnt know there was a fuel screen haha where exactly is it? & im looking at the float but i really dont know what to look for? sorry im kind of new to carburetors.

[Rkangel7]

If you took apart the carb make sure that the floats and float needle are installed properly. It is possible to put them in wrong which can hold the needle closed and not allow gas into the bowl of the carb.

[slightlybent47]

Look in the tube that you put the fuel line on. There should be a small screen down inside the tube. It’s about an inch long and tapered.

[atb400ex]

i look in the tube and i didnt see any screen/filter thing. is that bad?

[slightlybent47]

If you don’t have one in there then you need one. It’s just an extra filter but is put there by the factory. Don’t feel bad there are experienced guys on here that don’t know it’s even there. I would never have known myself, but mine fell out when I was cleaning it.

Here is a handy explanation on jetting.
http://www.atvriders.com/articles/jetting.html


Does it run if there is fuel in the bowl?

[jasonwayne222]

on a stock machine ur fuel screen is located in the tank, u would need to pull the tank, flip it upside down, and there will be two screws holding the petcock on the the bottom of the tank(tube that ur fuel line connects to) take this out of the tank and u will see the screen,

[atb400ex]

Does it run if there is fuel in the bowl? [/B]
I dont know how to get fuel in the bowl to see if it starts like you said?

[slightlybent47]

Originally posted by atb400ex
I dont know how to get fuel in the bowl to see if it starts like you said?

Ok try this.
With the carb on the bike, take a 17mm end wrench and loosen the plug on the bottom of the bowl. Make sure you turn off the petcock first. Then as you are taking the plug out some fuel should come out of the bottom of the bowl. If no fuel comes out then I’ll bet the float needle is stuck or not working.
Try turning the petcock on while you have the plug out, the fuel should run out.

[slightlybent47]

Here is the little fuel screen that goes in the fuel inlet tube.
Yes there is one in the tank as well. Most people don’t know about the one on the carb in the fuel line tube.


http://i41.tinypic.com/33ol8af.jpg
http://i40.tinypic.com/25hl5eg.jpg

[atb400ex]

So i took out the plug and some gas did come out. Thats good right? Im really confused lol.

[slightlybent47]

Yes that means your getting fuel to the carb. Now dose it start at all?

[atb400ex]

WHOA!!! Im not sure what happened but i put the pug back in and it started up no problem. Your a friggin genius man!!!

[slightlybent47]

Originally posted by atb400ex
WHOA!!! Im not sure what happened but i put the pug back in and it started up no problem. Your a friggin genius man!!!


Great…….Now you can go have some real fun!
Don’t forget to get you a filter for the intake tube, I think there about $12.00, but well worth the extra protection.

I cant take any credit, you were on the right track and by messing with it you probably flushed it out good and cleared up the problem.
Sometimes you just have to give them a little more love from time to time. Lol!

[ian0615]

as many times as i have taken apart that thing i have never noticed that either! lol ya learn something new everyday!