I have a pit bike and it splutters alot when i ride it

pull out the plug clean it off and while out crank it a few times do not give it any throttle action at all and whey you put it back in ,, in a few min close the choke and hit the throttle 1 time and it should start , start opening choke as it warms up

OK this ought to help you, I pulled it from this site: http://www.dirt-bike-tips-and-pics.com/dirt-bike-tires.html

Air pressure: When riding in sand or mud, lower the air pressure to around 10psi in the rear and 11-12psi in the front. This allows more surface area on the tires to contact and grip with the sand. For harder conditions on motocross tracks and trail riding over stones, branches e.t.c, inflate them up to around 13psi, 14psi max. If the air pressure is too low over hard terrain, you run the risk of causing a puncture or damaging the RIMS. Don't tighten the nut (on the air piece) to the rim. It's not meant to be tightened. Back it off to meet the valve cap once you've got the air pressure right.

Check the gap on the points and check to see if they're pitted or burnt. You might just need to clean them with some emery cloth or something similar. If they're pitted or burnt, they need to be replaced

could be a range of things only way to really know is to take it apart and look for blockages on fuel inline or damage to piston.

check for bad spark plug.has it got spark?also ckeck the carb for contaminated fuel and blocked jets in carb

has the bike been sitting for some time? Sounds like a classic case of gummed up low speed jets in the carbs. Pull the carbs and clean then out.

your spring might have broke on your throttle needle take apart have a look

Your bike may be jetted too lean. A common problem in these days of overzealous EPA regulations. You can tell if when you've cranked your throttle wide open and it splutters, if you back off on the throttle about 1/8 to 1/4 turn, it clears up. This is indicating that it is jetted too lean. When you close the throttle slightly, the fuel is being metered by the main jet and by backing off on the throttle a bit, you're cutting back on the air, thereby bringing the mixture closer to what the engine needs. Try rejetting the carb, Go up one or two sizes on the main jet, one step at the time.

Now, it could be too rich as well. If it splutters and blows black smoke out the exhaust, it either jetted too rich or the float level in the carb is set wrong.

Take care of the simple stuff first before rejetting the carb. Make sure your spark plugs are the correct ones and they are not fouled from overusage of the choke or enricher. If you allow the bike to "warm up" with the enricher on, plug fouling is common with this practice. I get the bike started and as soon as it will run without the enricher or choke on, I turn it off and keep the bike running with the throttle. Don't foul as many plugs that way.

It should be below. Not to sound rude, but I think you could have figured this one out yourself. You sound like a smart guy.

Thanks for using FixYa.

check the 4 stroke oil if it starts to splutter at half throttle