The Honda XR650L is a dual-sport (on/off-road) motorcycle with a single-cylinder engine. The engine is very robust and reliable, but it does need maintenance. Typical problems might include rough running, poor mileage, smokey exhaust or failure to start.
Start the engine. If it does not start, remove the seat and locate the battery. Use a voltmeter to test the charge of the battery. If it is below 12.3 volts, replace the battery.
If the engine starts, test the charging system of motorcycle. Use a voltmeter and touch the positive electrode to the positive terminal of the battery. Touch the negative electrode to a metal part of the chassis. The system should be charging near 14.0 volts, depending on the engine speed. Below 13.8 or above 14.3 indicates a charging system issue and may require a new rectifier/regulator, available from the dealer's parts department.
Let the engine cool down and disconnect the spark plug wire, then remove the spark plug with a ratchet and socket. Inspect the electrode of the spark plug. If it is bright white, the engine is running too lean (too hot). If it is black and sooty, it is running too rich (cool). Fuel mixture adjustments can be made to the carburetor to solve these issues. The procedures are outlined in your factory service manual.
Clean the spark plug and check the gap with a feeler gauge or spark plug gap tester. The optimum gap is from .031 inches to .035 inches. Re-install spark plug (or replace it with a new one). Connect the plug wire.
Start the engine. If the engine is still running rough, or white smoke comes out of the exhaust, it may need new piston oil-control rings or valve seats. If it sounds rough while running, it may need crankshaft bearings or a valve tune up. In either case, take the motorcycle to a professional mechanic for these services.
