hey guys, just wondering if I could get a little help here. Try to keep this short and sweet. So just recently picked up an 08 s40 and bike has been running great for the last month but ever since I ran out of gas last week it's been acting funny. I'll be riding along and all of a sudden it starts spitting and sputtering and engine dies when I'm coming off the throttle. My uncle( who's been Into motorcycles for many years and one hell of a mechanic) seems to be scratching his head also. I should also include the gas cap "meows" sometimes when sitting in the garage. A minor air leak I'm assuming, we took the cap apart, cleaned it, made sure the vent holes are open and it's still doing it not sure if that could maybe be my gremlin. Anyway we also richened the carb up about as much as you can to those stock mikuni's. Checked the petcock screen, clean and clear. Spark plug is good, def been running lean but it's good. This problem started about 4 days ago when I ran out of fuel. We had done those maintenance issues and for 2 days it ran solid no problems at all. Well I get out this morning and it's back!!!   any help would be appreciated. Thanks

The bike is completely stock. I will try the test thank you

Thanks for the input verslagen, I thought a cat was trapped inside the garage

It is a Cali bike, been here all its life, northern. I don't think the 1st or 2nd owners knew a screwdriver from a wrench, so it's needed some TLC for quite sometime. I tried the petcock test and right away it runs perfect, just rode it about 2 hours and no problems so I think that's my issue here. I'm going to try and replace the petcock to a raptor manual, should do the trick I think. The carb is getting a good run through this weekend

There is likely some clogging in your carb as others have pointed out since it started when you ran low on gas.  But while you are cleaning the carb and installing the new petcock take a look at your venting system, as you suspect, it shouldn't meow like a cat.

I'm not certain but I think those California bikes vent through a tube that goes to a canister.  Another bike I have is California legal and it has a complex system of vent tubes, canisters, and purging operated by pressure relief valves.  You might have a pinched tube or clogged one way valve.