Carbs getting gas but engine isnt?

Ok, if I may, could someone possibly explain how these carbs work. Im assuming the gas is gravity fed from the tank.. into the carbs but some reason I feel like there is has to some type of pulling to get the gas from the carbs? Would that occur when trying to start the engine? I believe there are vacuum lines too correct?

Im having troubles with screws stripping so right now I can only take off the float bowls of each carb and one top. Any suggestions on not totally damanging the carbs with taking these screws out or can I clean the carbs good without taking them fully apart and leaving them bracketed together? (I would assume no....) Thanks

CArbs work kind of like a venturi, they create a bit of blockage for the airflow to the engine, which creates a vacuum. The fuel gets sucked up from the bowl by that vacuum, and then flows into the engine along with the air. On bike carbs they'll have a slide which adjusts both the airflow, and changes the size of the outlet for fuel to get into the airstream as you throttle.

When you start the engine, as the piston goes down, it pulls in the air creating that vacuum, so it works the same way as when it's running. Vacuum lines are for other systems, not the engine, they just take advantage of the vacuum created by the engine and carbs.

The screws aren't actually philips heads, they're JIS, so they tend to strip with a phillips head driver. Sometimes an impact driver works better, but you have to be careful not to break the carb. Or there's instructions if you run a search here on how to create your own JIS. I usually take a dremel to them to make them flatheads, and then replace them with Metric screws of the same size, but a regular or hex key head.

You definitely need to disassemble them to get into all the passages good.

You can leave them bolted together but you'll want to get the tops off to check the diaphrams, clean the slides, etc.

Do a little reading online about how carbs work. Basically yes gravity feeds fuel into the bowls. It's then pulled out through the various passages by a difference in air pressure created from air moving through the carb throat (from air filter into the engine).

Del_Herring wrote: The screws aren't actually philips heads, they're JIS, so they tend to strip with a phillips head driver. Sometimes an impact driver works better, but you have to be careful not to break the carb.

I find that the phillips tips in my socket wrench set work pretty well. They're a little flattened already and they work pretty well on the JIS screws.

I usually strip about 1 in 4 using phillips heads. I have to press into the screw real good or they always want to pop out, which is when it seems to strip. If they aren't stuck the phillips are close enough, but if they're jammed in there good, it starts becoming a crap shoot.

Yes I am going to loook into those JIS screw drivers. Found many of the screws stripping, wish I would have researched in the beginning. I have put on "nut loose" and other loosening agents with no luck!! I wanna throw these carbs in to a ditch and burn em twice. As long as Im not the only person have problems I feel somewhat better.

To note, I sprayed carb cleaner in every hole possible in under the float bowl and the carb cleaner seemed to get out somewhere, was either leaking or blasting through one of the holes. I know this doesnt mean really anything but is there good news in the fact that I can see that its coming out somewhere?

btw, you guys rock!

Yes that is good news. Though you really will want to give these carbs a thorough cleaning, especially if they sat for any length of time. Wish I could find the post about which holes to cover and where the carb spray comes out. I tried searching for it without luck.

To get back to your original problem, the bike will start with starter fluid but won't run, correct?

I'd still start with a carb cleaning, set your float levels and check for fat blue spark on all cylinders. Get some sort of air filter in there. Simplest is going to be a stock air box with the stock air filter. You can try pod filters but may need to rejet if you go that route. Others here know more about that than I do.

Without an air filter in there to slow the air down it's going to be way too lean to run. The paper towel trick you mention might work, I've never tried it, but you need air filters anyway.

True and thanks for your response... I want to minialize the money I put into this because I bought it without hearing the engine. Other than starter fluid...( i know bad move.. but i like a challenge, if there is one lol)

I am trying to find an air filter for the bike now, and plan on buying spark plugs anyway, However if you come across that post let me know.

topper

Wish I could find the post about which holes to cover and where the carb spray comes out. I tried searching for it without luck.

Ima also work on getting this friggin screws out! will update

sometimes a small punch centered in the screw, and a sharp rap with a hammer will loosen the screw. Like a hand impact wrench. The impact would've been good before stripping the heads. Also a sharp chisel edge can be placed up against the head of the screw, then forcing in the left hand loosening direction, again a rap with a hammer. If nothing else you can get on some screw heads with a pair of small vice grip pliers.
Once you're back to getting the carbs apart, check all small passages for obstruction, including the small brass tube that you will see hanging down from the main carb body. this is the enrichment/ starter jet, which sounds like it could be plugged. It will supply fuel up to the choke/ enrichment circuit, so when you pull the choke, fuel should be able to go through that small hole in the end of the tube up to the carb venturi.

This link includes a free shop manual.
Scroll down to and download "The Bible."
Study the carb section, especially choke and pilot circuits.
kz.bike-night.com/

Good Fortune!

I have not been able to get to the carbs yet but I remembered something. LAst time i took the carbs apart i noticed there were no hanger clips for the valve needles and that was all four of the carbs. Is that normal?

tv219 wrote: I have not been able to get to the carbs yet but I remembered something. LAst time i took the carbs apart i noticed there were no hanger clips for the valve needles and that was all four of the carbs. Is that normal?

Do you mean for the float needle valves? The small wire clip that holds it to the float? These are in some models but not all. They won't cause a problem if not there.
Now if you are talking clips on the Needles for the Slide Valves, yes they Must have the small clip on each Needle to have it lift the needle out of the fuel jet.