What To Do When Your Dirt Bike Won't Start
There's nothing more disappointing than gearing up for a day of tearing up the track only to find out that your dirt bike won't start. Your prized possession's problems probably aren't too serious, so go through a short checklist of probable false-start causes will most likely expose any engine issues and send you off revving right away.
Step One: Check Fuel
Even if you're certain that the tank is filled, check anyway. Peak inside the tank and under the cap if you can. If you can't, shake the bike gently while keeping one ear close to the fuel tank. The tank feeds fuel through the carburetor, so be sure to that examine too. An easy process for checking if the carburetor is getting fuel is simply opening the overflow at the bottom of the float bowl. If liquid comes out, that means fuel is making it to the carburetor. If not, check that the fuel valve is turned on.If everything checks out, think back to when you last filled the tank. Old fuel can cause residue that clogs your system. If you've got clogs, you may have to clean the entire fuel line out.
Step Two: Check Air
Clean air for your engine really means a clean air intake, dependent upon the condition of the filter with a limited life. Make sure you maintain your bike's air filter, and that it isn't overly dirty. A dirty air filter could cause a fouled spark plug, which in turn could cause a faulty start.
Step Three: Check For Spark
Pull out your spark plug and ground it to the motor. Have an assistant kick the engine over (or pull the starter cord) and look for a bright blue beam arcing over the quarter-inch gap on the tip of the plug. If it doesn't spark, repeat.A fouled spark plug is easy to identify, as it will be covered with an oily residue. Again, this is more of an issue with your air filter, but it indicates that you will need to replace your spark plug immediately.
Step Four: Check For Proper Compression
A simple test can confirm adequate compression, and also tell you quite a bit about the engine status of your bike. First, you'll want to have the engine completely off. Hook up your compression gauge, open your throttle and begin turning your engine over until your psi indicator dial stops moving. It is recommended that your cylinder should have 100 psi to successfully start.
Note: If you don't have a gauge, most mechanics do and many will perform a compression test on your bike for little or no cost.
If nothing obvious stood out to you from the checklist above, it might be time to take your bike in to a mechanic. If you know your way around an engine and want to try it yourself, first check the vacuum seal around the piston area. This can be a common problem in older engines, and occurs due to lack of proper fuel maintenance over a long period of time.
A dirt bike needs several elements working in harmony to function smoothly. A full tank, clean air, a functioning spark plug, and proper compression for your bike are all essential to a successful start. You don't need to be a rocket scientist or even a mechanic to learn a little engine proper care practices and on-site maintenance.