Cough and sputter

I have a 99' fatboy that is having a problem I was hoping someone could help with. My bike will start and idol fine. If I start out with very little gas it will start off fine. As soon as I give it gas it start to pop, cough, and sputter. If I open the trottle completely it dies completely. I have the original carb and a built carb. I originally thought the built carb was jetted too big and was fouling out the plugs. So I put the factory carb back on and same issue. I checked the fuel for water and found none. Tried new plug wires and same issue. I did the V.O.E.S. test in the service book and it is fine. Does anyone have any other suggestions??

Thanks

Thank you. My next thing well be to check for leak. I only run 93 octane in the bike, and I try to only go to reputable stations, so I don't think it was gas quality. A few people have suggested the air leak. It just seemed strange that the last ride was fine then all of a sudden problems. Thank you for your response. I will let you know if it is a intake / air leak.

You are starving for fuel....

Since you are carburated and two different carbs were tried with the same result, look for a blockage in the fuel delivery system. The petcock, any fuel filter inline, or even the petcock intank filter. Sometimes the addition of alcohol in our fuel for emissions reasons will deteriorate and seperate the fuel line inside that will cause a restriction in fuel flow...You have enough fuel flow to idle but demanding more by attempting to rev-up is making the delivery so lean that it cannot run. Pull the fuel line off the carb and let it run into a can to see what the flow looks like....

That's my guess.....!

Bill C.

Thanks Clem,

I tried that already. I have really good flow. Thank you for relpying though.

Then I'm with Cowboy's suggestion as well....It would seem a fuel/air related problem from the "classic" symptom but you very well could have a spark management malfunction. But check as cowboy suggests first....

Bill C.

When my 78 sporty did that it was an advance problem. (Electronic advance not mechanical)

remember big problems usually have small solutions. you mention the plugs fouling might check the timming and seals/gaskets like cowboy said.

Thank You

I would like to thank everyone for your help with this issue. It has been resolved. I still don't understand it but it turned out to be my AIR FILTER!!
After I replaced the intake rubber and the back plate gasket it was still doing the same thing, so I thought if it would do that with too much air, maybe it would also do it with too little air. So it took the air filter off and went down the road and it ran perfect. The reason I don't understand it is because the air filter looks to be in good shape. It is a K&N and I can see no build up of any kind. I even tried cleaning the filter with K&N filter cleaner and oil. At least I know what it is. A new filter and I am back on the road.

Thanks again everyone for taking the time to help a stranger.

It's not uncommon to over-oil the K&N filters. Then it runs rich. Had the same problem. Recleaned and was more conservative with the oil and it ran great.

You fixed it, thouigh, so never mind

Skyking,

Thanks for the info on the over oiling. I will keep that in mind when my new Big Sucker needs cleaning.