TIRES
These commonly overlooked components ironically are the most critical for a safe and comfortable ride. The performance gains (or hindrances) are very significant as well. Tires are the unsung heroes of the motorcycling world, and they'll take care of you if you take care of them. They don't ask for a lot either; proper inflation is about the extent of the required maintenance-so give 'em what they want.
The CBR had a "new looking" rear and a mismatched front that appeared to have a lot of tread. In actuality, the rear was beginning to dry rot and the front was so badly cupped that it caused the front end to undulate dangerously. Despite the owner's claims of "new tires," these rubbers were ruined and needed to be replaced.
CONSEQUENCE: The cupped front tire doesn't have a consistent contact patch and can lead to tank slappers, instability and poor grip overall. The rear has been through more heat cycles than your grandma's cat, and eight years of weather exposure have reduced it to rubbish. Do burnouts with it, but don't ride beyond the neighbor's driveway (where you've performed the aforementioned smokies).
BRAKE PADS
Weather is a powerful force and can make dust out of even the harshest substances. Imagine what years of exposure to the elements can do to the organic material in a brake pad.
Upon inspection the pads were not only worn but also pretty crusty, so we replaced them with new ones.
CONSEQUENCE: Glazed over, hardened brake pads don't offer the stopping power needed once you get moving.
OIL/OIL FILTER
Oil is the lifeblood of any motor-we all know that. Changing the oil and filter is a quick and easy job, and should be routine maintenance. Although this bike's exterior looks clean from a distance, it has some telltale signs of neglect (chain, air filter, tires) and you can bet the oil and filter are in a similar state.
CONSEQUENCE: Dirty, broken down oil doesn't have the ability to properly lubricate a motor-that's common sense. What could go wrong? There are lots of ways a motor can "blow up." To learn your engine's preferred form of implosion simply run some grungy old oil and a funky filter. You'll soon have your answer.
AIR FILTER
Dirt can corrode combustion chambers and hinder the all-important air/fuel combustion process in the cylinders. Why decrease performance for the price of a simple air filter? Depending on how dusty your environment is the air filter could need replacing (or cleaning) on a regular basis. When we popped the lid on our CBR's airbox we were expecting a family of mice, but instead it was a horsepower-robbing petri dish of grime, dirt and filth.
CONSEQUENCE: A dirty air filter will decrease airflow, thus robbing power. Also, dirt (or worse) can be sucked into the motor and cause major damage.
CHAIN/SPROCKETS
Another hapless hero is one that your bike would be useless without. The chain and sprocket combo propels you forward, but if either are neglected the consequences can be severe.
Our CBR's chain looked like it had spent a few years on the bottom of the ocean, and the rear sprocket was missing more teeth than Cletus the local yokel.
CONSEQUENCE: A rusted and worn chain can snap, causing major injuries to your body while destroying the engine cases. Worn sprockets deteriorate a chain quickly, and also steal power from its ultimate destination-the rear wheel.
SPARK PLUGS
They can go bad, or "foul" for various reasons, but new plugs should be part of a general maintenance routine along with oil changes and tire pressure adjustments. Inferior spark plugs (use the suggested stock plugs or better) won't perform at peak potential for long, and once they deteriorate the motor will begin to struggle. Poor starts and general sluggishness are symptoms of old, worn out plugs.
The CBR was running on three of its four cylinders due to one spark plug's complete failure.
CONSEQUENCE: Worn out spark plugs only get worse, and one morning those "hard starts" will end up being a "no start."