dirt bike trouble starting?

Question

i a recently bought a dirt bike from a friend and it's been sitting awhile so if you have any helpful hints,tips it will be greatly appreciated

Answer 1

if the bike has a battery, check that first. motorcyle batteries are fragile and one that has not been charged or maintained for a few years is most likely shot. remove the batt. from the bike and clean the + and - connections. make sure the water is up to the top line on the side of the batt. case. with the filler caps removed put it on a low amp charger, not more than 10 amps. if after 10 min. to a half an hour you don't see bubbles, replace the batt. sometimes a stone dead batt. will lose it's polarity and not take a charge. sometimes you can bring them back by running 2 heavy jumper wires from a good batt. connect the jumpers pos. to pos. and neg to neg from the good batt and the one you are trying to charge. put a charger on the good batt and again watch the batt to see if it starts to bubble/gas. if the batt will not take a charge or has been frozen at all throw it away and get a new one and put it in the bike. after you have a known good electrical source, or the bike doesn't have a batt, move to the next step.
pull the sparkplug and connect a known good plug to the plug wire. with all switches turned on ground the plug to the engine and kick it over a few times. it's a good idea to do this in a darkend or shaded area as it's easier to see the spark. to ground the plug, put the metal part, about were the wrench goes, against the bare metal of the engine. if you don't have any spark you have more problems than I can help you with here. you should see a blue spark between the electrode and the plug ground....little bent over piece at the tip of the plug.
now, turn the gas off. remove the gas line/hose from the carb and with some gas in the tank and the hose in a small clear container, to catch the gas, turn the gas on to reserve. gas should come out of the line and into the container. if it does not, the valve/petcock needs to be removed and the small screen and the valve needs to be cleaned....the gas tank also. after you get a small amount of gas in the container look to see if it is clear without anything floating in it. if this is ok replace the line on the carb, if not clean the gas tank. if there is an in line filter on the gas line make sure that is clear. the gas should be off at this time.
now remove the air box cover and/or air cleaner. this should be free of debris, you would be amazed at the things i have found in the air cleaner on bikes that have been sitting....acorns, nests all sorts of crap. if this is ok and the air cleaner is servicable, next step.
turn the gas on, with at least a gallon in the tank, and hit the float bowl area of the carb with the handle of a large screwdriver. don't hit it any harder than you could hit your upper arm without it hurting. watch the carb for a minute or two and check to make sure the carb is not flooding. if it's flooding you will see gas coming out and dripping off of it. if this happens turn the gas off and remove the carb for repair. if all is ok, next step.
with the spark plug still removed, pour about a pop bottle cap full of clean gas down the sparkplug hole. replace the plug and with all switches and the choke on, kick the bike over. if it has spark it should start, assuming the internal mechanical parts of the engine are sound. if it starts and dies, pull the plug and try another capfull of gas. if it starts and dies again try kicking it half a dozen times with the choke off and the throttle wide open. if it still won't run remove the carb for repair. if it starts and stays running check that it idles smooth and accelerates without popping or having flat/dead spots. if it runs ok throw 3 capfulls of a good fuel system cleaner into each full gas tank for about 4-5 tankfulls.....now go ride the bike. if the bike runs rough, won't idle or has flat/dead spots on acceleration, remove the carb for repair.
even these simple carbs can turn into a nightmare for someone that doesn't know what they are doing. if the carb needs repair and you don't know what you are doing, have someone that does take it apart.
be carefull, you are working with gas, and it can catch fire and burn you.

Answer 2

The first problem with bikes that have been sitting is the old gas that "gums" up all the small holes in the carb. I'd suggest replacing the gas, take the carb completely apart and clean every little hole you see with aerosol Chemtool carb cleaner, $3.25 at walmart. Of course check the tires to make sure they have the right pressure and no problems. Check the oil level, replace the spark plug if it looks black down inside the inner walls; nothing makes a bike run bad than a dirty carb and a bad spark. If it ran before it was sitting, that should be sufficient. If not, there's bigger issues such as a rusted piston rings or malfunctioning valves that would make it near impossible to start. If you have trouble starting it, take off the air filter, which you should also clean or replace, and spray some Chemtool in the intake. Anything else? Just ask!

Answer 3

clean/replace air filter, clean out carborater, take out old gassoline as it will gum up over time. Replace spark plug, charge battery if it has one. Replace transmission oil too.

Answer 4

Install a new spark plug.
Clean the jets in the carburetor.

Answer 5

Battery?