"Take care of your Honda and it'll take care of you" is a catchphrase used often by Honda riders. But even though Honda motorcycles are well known for being powerful, reliable workhorses, they are not immune to technical failure. Knowing how to diagnose one's own motorcycle problems is an indispensable skill to have when traveling on two wheels or serious commuting. The best Honda-certified mechanic cannot fix a motorcycle if he does not know what is causing it to fail.
Check the fuel flow to the carburetor. Be sure that the fuel petcock is in the "On" or "Res" position and that there is fuel in the tank. Check the breather on the underside of the tank. If it is clogged, fuel will not run through the line.
Check for spark. Examine each spark plug for rich mixture (black or brown residue on the tip) and perform a spark test on each by grounding it against the crankcase or cylinder head and pressing the starter button. If there is no spark, check that your starter is working correctly and that the battery is charged.
Test cylinder compression with a compression gauge. Without compression, the spark plugs will not ignite fuel correctly. If compression is low, check for leaks or other damage to the cylinder head and for worn cylinder and piston rings.
If the engine starts, but then dies quickly, there could be a multitude of issues, including but not limited to improper choke adjustment, intake pipe leak, incorrect ignition timing, contaminated fuel and incorrect carburetor adjustment. The most common, however, is a worn or old air filter. Air filters are inexpensive ($30 to $40 dollars for most Honda motorcycles) and easy to remove and install.
Honda motorcycles are notorious for their "dead spot" just after idle. If your motorcycle starts and idles well, but dies when given a small amount of throttle, you may need to shim the carburetor needle in order to deliver fuel to the engine more quickly.
