Well, I'm no expert because I'm new to the Rebel world myself, but from what I've learned on here it sounds like the "puke tube" (yea the one with all the gunk in it) got filled up and clogged the carb. Maybe caused the float to stick? Not sure. Mine is an '03 and it has 3 hoses hanging underneath, the puke tube has a plug in it with a squeeze clamp. I'm thinking get some carb cleaner with the straw and spray it out from the carb side (don't blow anything back up into the carb) and spray out the carb as well.
I'm sure others with lots more experience than myself will chime in to help! I've learned a lot in the month I have been reading this forum. Lots of great guys and gals with tons of knowlege here! They'll have you up and running like new!
And BTW Welcome!

 

First off, Welcome aboard Motorgirl.

The drain(puke) tube is usually caooed like Pinto describes. It drains the stuff that is pulled from the crankcase , run through a seperator, then up through the airbox.
It's part of a PCV system. (Pinto, don't blow carb cleaner up there. You risk getting carb cleaner in your crankcase)
That tube needs to be drained at least every oil change and in wet conditions more often.

What I suspect is some varnish (stale gas deposits, brown and sticky smeels like gas) or possibly rust had made its way
through the fuel line and is not allowing the float needle valve to shut. If the line that you blew in to is the overflow.
The carb bowl over fills and some runs back through the mouth of the carb into the air box, saturating the air cleaner and making it hard to get air.
Some also would run into the cylinders.
CHECK YOUR OIL. If it is suddenly over filled or smells badly of gas, change the oil.
Gas in the oil is a sure way to wreck bearings. Did you turn your petcock valve off hwen you park it for the night? If not, is there a puddle of fuel?
You may need to remove and clean the carb. Some Seafoam through the fuel might clear it up for you.

These are all just educated guesses. Some more specifics could nail it down further. How long have you had the bike? How much riding time has the fuel in it seen?
Did it sit for a long period of time?


When re-oiling the air filter, you don't need to thin the oil. Just use clean engine oil. 10W 40 is fine. The oil isn't there for lube, it is what catches the dirt. The foam element is just the "frame" that allows to oil to do the dirt catching.

 

Welcome motorgirl, I have to say puke tube too. A lot of people check it at every oil change. It would depend on the area were you live though, on how fast it fills. Drier air versus more humid air. I seem to be good about twice a year on emptying.

 

it is ridden every day. ive had it for 5 months. i have put about 3000 miles on it. oil was changed when i first got it.

so.... im gonna change the oil, use seafoam, and get some carb cleaner..... ill let u know how it goes. thankyou so much for the help so far.

 

Welcome and good luck, these guys are great and know so much.

 

Try this, it works for me when the float valve sticks open.
Turn off the fuel at the petcock. Drain the carb bowl by loosening the screw underneath the bowl. Once it's done draining remove the fuel line from the carb. Remove the drain hose off the bowl. With the drain screw on the bowl still open blow some canned air up thru the bowl drain. The pressure will back flush the float needle and should clear the debris. Close up the drain screw, re hook up the fuel line and turn on the fuel. It should not leak into the airbox now. Check the oil and start it to see how it runs now.

 

so- changed the oil, used seafoam, got CRC clean-r-carb and cleaned the outside of the carburetor, cleaned and lubed the air filter with my motor oil, petcock is always off when not in use (and doesnt leak) started it up and ran it around the block a few times, did not leak gas through air filter (that i know of) and it ran well.... until i got home.

i pulled in and put it in neutral, it seemed like it was idling higher than it was before i left. i turned it off and waited a minute. then tried to turn it back on. it will not start now. ive tried about 20 times. even if i give it a little throttle it does nothing. i turned the choke up when i tried to turn it on and it had no effect and still would not start.

i only have the choke up while warming up, never while riding. this is getting frustrating

i am going to try bB2ners suggestion next... maybe it is a float valve

 

If you don't drain the bowl and blow it out, whatever is keeping the valve from seating is stuck there. This method blows the junk back out the fuel inlet. Make sure you have safety glasses or stand clear of the fuel inlet. It might spray in your face.
My 400s left carb kept leaking fuel out the overflow till I did this. Now it's normal again and I leave the petcock open all the time.

 

And if you don't have a fuel filter, you need to add one!

 

bB2ner- first of all, thankyou for all the help.

2nd- i dont have a clue where any of that stuff is on the carb. do u have a pic with an illustration or can u call me? in return, i will mail u a painting or do a graphite portrait for you.

if you decide to call, the number is 225.218.7480

this is what my carb looks like from both sides (on the 2nd pic, the taped wire is the battery wire, sorry it was in the way)

 

I marked where the stuf bB was talking about is on your pic.

 

u guys are awesome but now im drunk and am not gonna attempt this right now - tomorrow is gonna be the day when i tackle this.... sigh. i hope i can find the screws. i looked all over for them when i saw bB2ners post and couldnt see them.... maybe i missed them?

thank you thank you thank you!!!!!!

 

And unless bB2ner has switched it out for a gravity feed, the petcock on his 450 is vacuum operated. This means it will only flow fuel when the engine is turning over. The petcock on the 250 is gravity flow, meaning if the float valve in the carb gets stuck, it will continue to flow, putting way too much fuel in the cylinder and possibly contaminating the engine oil. That's why turning the petcock off after every ride is recommended with gravity type petcocks.

 

Nope, it's not the 450 rebel. I was talking about my CB400T Hawk with basically the same petcock a rebel 250 has. I'm lazy when it comes to petcocks. I know I should close them but seldom do. My wife always closes hers but she doesn't ride everyday like I do.

Motorgirl, the screw for the bowl drain is kinda small so you might need a skinny flat straight screwdriver for it. I'd advise getting another piece of hose to place over the drain outlet so you don't have to mess with the one already run on the bike. No sense trying to re route it. If this doesn't fix your problem you may need to rebuild the carb and have a new float valve installed.