Every season before we hit the road, it is a good idea to inspect the bike, clean it up, and do a little bit of maintenance. K and G Cycles (www.kandgcycles.com) is proud to designate May as “Motorcycle Maintenance Month” so we find it fitting we post a little about your maintenance needs and recommendations.
One of the simplist items to address is the spark plugs. Most V-twin motors call for 10,000 mile intervals on the spark plugs unless otherwise noted. I personally prefer new plugs every season, especially since they are relatively inexpensive, and directly affect my performance and fuel economy. You should always look at the color of your plugs when changing them because it will tell you exactly how your engine is performing. In general, a light tan/gray color tells you that the spark plug is operating at optimum temperature and that the engine is in good condition. Dark coloring, such as heavy black wet or dry deposits can indicate an overly-rich condition, too cold a heat range spark plug, a possible vacuum leak, low compression, overly retarded timing or too large a plug gap. If the deposits are wet, it can be an indication of a breached head gasket, poor oil control from ring or valvetrain problems or an extremely rich condition – depending on the nature of the liquid present at the firing tip.
Here are some conditions to look out for.
Although there are many different cases, if the insulation resistance between the center electrode and the shell is over 10 ohms, the engine can be started normally. If the insulation resistance drops to zero ohms, the firing end is fouled by either wet or dry carbon. We often call this “Gas Fouled” because unburnt gas remains in the plug end. The accumulation of deposits on the firing end is influenced by oil leakage, fuel quality and the engine’s operating duration. Short runs are more prone to have deposit build up over engines that have been given a chance to reach ideal operating temperature.