No gas to engine- what the heck is going on?

[Lucien Harpress]

My entire problem is pretty much summed up in the title. Simple fact, my engine isn't getting any gas into it. I get fuel through the lines, into the carbs, and (at the very least) into the carb bowls. Somewhere between there and the engine, the gas just isn't getting through.

Now, I know what you'll say- dirty carbs. This ISN'T the problem. I've been though all four carbs three times. Tore them completely apart, soaked everything, and everything is clear.

What might be the problem has to do with the needle/gasket assemblies. While cleaning the carbs, I rubbed a bit of the oil from the cylindrical drum part. Now all four aren't as "snappy" as they used to be. Is there a way that these might be getting stuck and not allowing the fuel to flow? (I'm not 100% sure how these carbs work exactly, so I'm not sure. I'm just trying to narrow down the potential problem areas.)

I really don't want to tear this bike apart any more. It would just be nice to know what the heck is going on.

[tw1980]

I'm a little confused.I don't see how if the carb bowls have gas in them you can have a fuel flow problem.Maybe if you described the symptoms in a little more detail I could be of more help.I doubt all 4 carbs are gummed up at the same time,unless your working on restoring a neglected bike.Terry

[randy]

Do you have spark?
Do you have compression?
As a last resort, try a teaspoon of fuel in each cylinder, replace the plugs and see if it fires. That should rule out spark/compression as the problem.

[dbeardslee]

Lucien - When you had your carbs apart, where did you set your float height, and were all the float pins straight?

[boyat68]

How did you check to see if you had fuel in the bowl? If you took the bowl off, then that may have let the float fall down and fuel to flow and be a red herring. If you took the drain screw out of the bottom of the bowl then it is correct that you have fuel in the bowl but it is not being atomized up through the main jet or the pilot jet. The only sure way you can see what is happening is to set up the Ken Talbot rig and check the flow while on the bench.

[Ivan]

One thing I have seen commonly done wrong in carbs is the float needle. There is a little wire hook on most needles that fits AROUND the tab in the float. Some times people put the hook under the tab, which is actually on top when the carb is right side up. This effectively sets the float level VERY low, but will still show fuel in the bowl.

I would check that. The spring supported pin needs to touch thed tab.

[Lucien Harpress]

Okay, let me back up a bit and see if you can see something I did wrong.

This whole thing started with sluggish acceleration. Realizing the problem might be dirty carbs (with a bit of help from this site), I took them apart and put them back together (clean) the first time. The first day it ran pretty good- not perfect, but better than it did. The next day, two cylinders (1 and 2) dropped off on me. The day after that, none of them would fire. The most I could get was a brief startup (it would fire two or three times) if I gave it full choke. It would do that once, then nothing- the starter would just turn the motor over. I took all the carbs off again, cleaned them, put them back on- same thing. So I did it a third time, this time taking out the mixture screws and cleaning them as well. Put them back on- still nothing.

Fuel is definitely the issue. I got some starter fluid, and spraying that into the carbs will get it to fire for a second or two. Then- nothing.

I will check again, but between the last two times the carbs were off, I took the drain plug out of the bottom of one carb bowl, and there was gas coming out. I'll check again tonight, and check all four of them, just to be sure.

The float needles I didn't adjust from their starting position. All the needles are hooked back over the tabs where they started.

If the needles are indeed the issue, the only thing I think I could've done wrong was soaking them in carb cleaner. I noticed (too late) that the tips are rubber, not metal, and a few of them look a bit deformed. Could this be the problem?

[dbeardslee]

If you soaked them in carb cleaner and you saw that they were visibly deformed the viton tips might be stuck in their seats. I would think it would be more likely they wouldn't seal properly, but if they were soft when you installed them, who knows. One thing is pretty clear - if you saw that they were deformed another trip into your carbs is probably in your future. I'd get some new float needles and replace the ones you've got. It's usually a good idea to fix the stuff you know is wrong first.

[Crazcnuk]

If the tips are stuck, blocking off fuel flow completely (pretty good trick for all 4 at once!) you could take the drain plug out, wait a few seconds and the fuel would stop coming out.

My question would be, though, how did fuel get into the bowls at all, if this were the case.

You said that it fires a couple of times on gas, then dies, and it does the same thing on ether?

As someone suggested put 1/2tsp or so of gas in through the spark plug hole and see what happens. I usually only put it in 1 cylinder, but you can try all 4.

Another thing to try is take the tank off, and blow through the fuel feed lines. you should be able to blow through it and hear air going into the carbs past the float needles.

You can do this all on prime to take the petcocks out of the equation, for the moment.

[tarzan]

When I have that problem I just open the throttle and spray starting fluid in each carb,then hit the start button.It should fire up and run for a few seconds.

[Lucien Harpress]

I'm going to take a look through the fuel lines when I get the chance. I took the drain plugs out of the bottom of the bowls with the petcocks set to prime, and after a bit of fuel flowed out, nothing.

When I put the carbs back on the last time, I added two fuel filters and a bit more fuel line. I "primed" the lines by pouring fuel into them, and this is what I think got into carbs. I'm hoping that the way I routed the fuel lines is the problem I'm dealing with, and if I can solve it without taking the carbs off again, that would be great.

[cywelchjr]

I'm going to take a look through the fuel lines when I get the chance. I took the drain plugs out of the bottom of the bowls with the petcocks set to prime, and after a bit of fuel flowed out, nothing.

When I put the carbs back on the last time, I added two fuel filters and a bit more fuel line. I "primed" the lines by pouring fuel into them, and this is what I think got into carbs. I'm hoping that the way I routed the fuel lines is the problem I'm dealing with, and if I can solve it without taking the carbs off again, that would be great.

It sounds like someone might have modified your petcocks like mine were done. Modified them so that on was always flowing, reserve was normal (vacuum actuated) and prime was off with no flow. Also the filter towers that were put on made it so I had 15 miles of gas left when I went to reserve.

Oh, wait, my bad, they work as prime being reserve and vacuum controlled flow, on is on and always flows and reserve is off. Of course those are on my leaky tank, so I have good petcocks on my current tank. I THINK that you get this type of behavior by getting the petcock lever switched from side to side. If I'm right, you might be able to just dissassemble them and swap the levers on them. Then again I could be wrong.

[Crazcnuk]

Sounds like mine, after putting on fuel filters.

The extra line length kept kinking, and it would 'run out of fuel' while i was going down the road.

Funny part was it would run fine for a few days, then all of a sudden the lines would be kinked.

It did this to me several times until I got the lines the right length and tucked in properly.

[Lucien Harpress]

Success!

I'm not, not, not, NOT going to get my hopes up too high just yet, but I have some good news.

I went and filled the fuel lines completely up with fuel, hooked everything up the way it should be, went to start it-

and it caught.

Fired right up. Even better than that, the throttle response through the first 3000 or so RPMs (the problem I was trying to solve in the first place) seemed real solid. Ran fine with the choke on for about five minutes, then with the choke off settled down into a nice, steady rumble.

I want to wait for a few days to see if I'm actually getting gas out of the fuel tank or I'm just burning the stuff in the lines, but after two weeks of problems, I'm just ecstatic it runs.

I'm still going to need to tune it- it backfires a bit more than it used to, but after removing the mixture screws I wasn't able to re-set them to where they were before. All of them are set at two turns out. A project for next week, maybe.

Once again, thanks for all the help. I would honestly be lost without this site. Thank you.

(The only niggly thing is when I was filling up the No. 3 and 4 carbs, when I reached overflow level I was getting gas out of the airbox. This might be a buggered float needle not closing tight enough, but if the bike functions fine in the future without this being a problem, at this point I'm willing to let it slide.)

[DGXSER]

If you run it farther than half a mile, then I would bet you ran through the bowls and lines. Experience tells me that is about the distance you get when you forget to turn the petcocks on.