Fuel cut issue. 250sx**still a problem**

[STiForester]

Ok so this is tricky. I took the filter out of the petcock and replaced the O ring and cleaned the filter. I also replaced the fuel lines and fuel filter... When I get on it for a minute I notice it will die and the fuel filter is usually empty but if I let it idle for a while gas will fil about 1/4-1/2 full and runs good. But when I open the gas tank cap it makes a whoosh sound of air rushing into the tank. Than the fuel fills into the filter again quicker than if I leave it closed. What is going on?? Is something just bad with the breather in the cap... Any ideas? I think that's what it may be but I'm confused on how to come up with a solution for this problem.

[dougspcs]

Bad fuel cap..been there, done that!

[STiForester]

Really?? What's bad about it? It's only a threaded cap tho? Hmm interesting.

[Headsup]

Maybe it is not venting right, Causing the fuel flow to be limited. Seems it since it pours freely while the cap is off. Drill a hole in it and stick in a breather tube?

[STiForester]

Yea I may but Id hate to ruin an original cap on an original bike. Guy drilled holes in the top of the air box other than that everything is stock and original but yea it's weird. I can hear an obvious whoosh like opening a 2 liter but it's sucking air in instead. So when it bogs and starts to die ill open the fuel cap and it usually jumps back to life within a few seconds. The filter inside the petcock was flawless and clean as a whistle

[1985BigRed250ES]

take a drill bit and drill out the vent hole in the cap and that should take care of it

[SteveCZ28]

yea its common sense here, when you take the cap off and you hear that rush of air into the tank, its pretty plain and simple the cap is pluged. like mentioned above drill the breather hole that is already in the cap, and youll have a perfectly fine trike again

[STiForester]

Okay thanks guys. Will do after work

[3wheely]

I just took my cap apart for the exact same problem yesterday. Cleaned it all out and put it back together and works fine. The quicker solution is drilling the hole but I like to take things apart and learn something new.

[STiForester]

Yes as do I. But how did you take it apart?

[atc350xer]

My '85 Big Red came with the rare optional hole drilled into the cap. Obviously, a common problem.

[3wheely]

The cap is actually two pieces. Flip it over and you will see the seam on the outer rim. It's kind of a pain but a flat head and hammer should do it. Don't pry just tap all the way around the rim until it comes apart. Be careful there are inner pieces that will fall out and then you won't know how to put it back together.

[STiForester]

Yea I guess I'm just gonna have to drill it later today

[STiForester]

Ok thanks buddy. Gonna get on it today But if I drill. How far should I go?

[Headsup]

Drill the vent out. So it can get air in there, Worse comes to worse, Drill all teh way threw it and stick in a breather tube

[STiForester]

Will do. Thanks homie

[STiForester]

Ok so I drilled the vent cuz the cap looks like it was pressed together and looks like a real pita to get apart so I drilled it out... I should have thought about this first. Now there is metal shavings all inside that are very tough to get out. I've been shaking the cap non stop for about half hour and shavings are still falling out. The cap works but worries me. Just gonna have to rip it apart I guess.

[3wheely]

Try and temporarily tape or seal the drilled hole in the bottom of the cap and blow compressed air in the top hole (take the cap off the tank to do this). I did this with mine and it separated the pressed together pieces... the air has to escape somewhere. Not sure if it will work now that you've drilled a hole but it's worth a shot.

[STiForester]

Yea but it has the on and off switc at the top... So there is not really a hole. Just a place for air to escape for venting ya know. Would be nice if it was a regular cap where I could still a hole and put a breather

[3wheely]

Oh, I thought you took the switch off and drilled a hole straight through. I pried mine off carefully with a flat head. It just snaps into place. It went back together fine. Not sure how big of a hole you drilled but I wonder if a shop vac would get most of the shavings out by suction? just a thought. I can't imagine with how thin the cap is there is that much shavings in there.

[STiForester]

Hmm your right I will try that vac idea. But I pretty much teamed it with a drill smaller than the original hole. You can pop that switch off with a screwdriver? It went back on fine?? What position did you have it in

[3wheely]

The on position gives a little more space to pry under. It takes a little work but just do it carefully moving from one side to another so you don't break it. It will eventually pop off. Once you put compressed air inside that hole it should pop the seal in the pressed area at least it did mine. It didn't pop it all the way off but it gave a good starting point. Then just gradually tap all the way around until it comes completely apart. Make sure you pay attention to how the innards come apart so you can put it back together. It's not that difficult. I would do this as a last resort if you can't get the shavings out. Even if you didn't get it put back together correctly you could probably drill a hole all the way through and stick a vent tube in.

[STiForester]

Drill a hole all the way through the on off switch ya mean? I think it's working now. My fuel filter is full now I just want to get those shavings out. Shop vac sounds perfect. Thanks buddy I appreciate it.

[3wheely]

No if you ended up taking the switch off to get it apart you could always drill a hole. I would leave it and try to get those shaving out if it's working. Just use the vac and shake it around until it all comes out.

[STiForester]

Will do right after work. Thanks for the info.

[STiForester]

ok so i drilled it out and popped the switch off and made sure it was clear... im still not getting fuel down in there.... could the little filter inside the tank be clogged? i can see them and they look fine.... im so frustrated at this point

[brapp]

well the woosh oif air indicated the vent not working, does is work with the cap off? if you need any parts i ahve a entire parts machine and even have a 2nd tank and cap if you need one.

[STiForester]

No I drilled the hole and it gets plenty of air now. But fuel still doesn't want to fill the filter

[atc500x]

The seal in the petcock is bad and block the line.....Change the petcock or take it appart.I drill the rivets and replace it with M3 bolt

[STiForester]

When I took it apart there was a bowl and a screen with mess and an o ring. I didn't really see rivets

[STiForester]

Here is the diagram. What could be wrong??? I'm stumped. I guess something in petcock

http://www.cheapcycleparts.com/model_years/310-honda-1985-all-terrain-cycle-atc250sx/assemblies/6190

[STiForester]

I cleaned out that bowl and put a new o ring in a it worked great for the first day now it's not letting fuel through again unless I blow compressed air in the tank

[Headsup]

Ive had the same problem,

I took petcock off completly. Took insides out. Stuck a screen in it, And worked fne.

Try taking insides out of petcock, and try like that.
If your getting fuel u know the insides are bad, Or need replaced/.
If u still dont get fuel. It could be something blocking the passage way on the bottom of your tank? The hole where the petcock screws in,
Also make sure u check your fuel lines. Also make sure their proper Width. A to small of Fuel line will not let fuel pass threw it.

Also the onn off switch to the gas. Make sure u can blow threw it when the fuel switch is on. If not, There is your problem.

[Tippmann98]

When you take your fuel line off the petcock are you getting a good steady stream of gas pouring straight out of the petcock or is it dripping out?

You can get a brand new one on eBay for $26 shipped to your door. I had a bad petcock on my 250sx that I couldn't get cleaned up so I bought a new one. It worked great.

[3wheely]

I would do ^ all the above. Spray some carb cleaner through all the openings in the petcock. Then blow some compressed air through as well. If there seems to be no blockages then move on to fuel lines and such. I put an inline filter between the petcock and carb on mine. That may help you later on to tell if your getting fuel to the carb without guessing or pulling lines.

Oh yeah, what's the inside of your tank like? Clean, rusty, trash in the bottom?

[STiForester]

Yea I have an inline filter. Clear so I can see. I took the fuel line off my Tecate and put an inline filter on it and put it on the sx. It's a rubber line not a hard line. And when I opened up the bottom bowl of the petcock there was an o ring in with the mess screen but it was smushed and really effed up. I replaced it so it has to be a petcock issue cuz it gets fuel but something seems to be blocking it

[STiForester]

The inside of the tank isn't too bad but if the gas sits it gets orange from rust

[Tippmann98]

So the tank has some rust in it? Even a little bit will clog the petcock right up.

[STiForester]

Yea a little. How can I fix it so the petcock will work?? It's not much but it is enough to make the gas turn orange After it sits for so long

[STiForester]

What part of the petcock gets clogged? The screen in the bowl? Or the stem into the tank

[3wheely]

Remove the petcock and spray every opening of the petcock with carb cleaner. Make sure the valve is open. It should come out another end somewhere. If not you have a clog. In that case try compressed air. If you have rust problems in the tank you may always have issues. At that point either re-coat the tank or get another one.

[STiForester]

Yea. Thanks buddy I'll do that today and let you know. Does the petcock have two bolts or screws or is it one with a nut next to the tank?

[3wheely]

It's all one piece with a nut that you unscrew. Once you loosen it the whole assembly will slide out of the tank. Don't forget to drain the tank first.