You have feverishly maintained it following all the manufacturer's recommended intervals, kept immaculate records and always performed a thorough after-ride cleaning along with checking off all the boxes on your pre-ride checklist.
But still, no one and no machine can escape Father Time.
Riding wears out almost every single facet of a dirt bike and despite our best intentions some parts eventually give out and it seems always at the most inopportune time. Most maintenance needs like the oil, various filters and even internal engine parts like the top and bottom ends have a pre-determined lifespan. Thus the routine maintenance schedule. But others tend to last much longer and for the most part get left alone and then quite often forgotten, unless other parts run afoul or a crash impacts performance.
Therefore, if you ride a five to 10 year old dirt bike you may encounter these common problems that you can get a jump on and address during your next scheduled maintenance day:
Bearings and Seals
Bearings when lubricated properly last a long time. In fact, so long you probably tend to forget about them. Dirt bikes have a several areas that require bearings for proper performance including:
Once bearings have exceeded their use you often hear a grinding sound and experience some handling issues while riding. Quite often a rider forgets to routinely apply grease to the bearings which can minimize operation life but even when carefully maintained the bearings will, one day, simply cease to function properly. Dirt, moisture and wear and tear eventually break them down. If you can't remember the last time you replaced the bearings (and you probably will since it's a pain) then consider replacing all the bearings but at the very least give them a visual check and apply some fresh grease.
If you have never changed the carburetor O-rings then think about replacing them if your bike falls in the five to 10 year old range. These rings, albeit quite simple, seal the carb and float bowl. A pretty big deal because when they go bad you get a fuel leak from the float bowl. Sadly seals don't live forever and the seals on your dirt bike don't last forever either succumbing to age and eventually get brittle. However, those of you who use ethanol based gas might find the need for a carburetor O-ring change sooner rather than later.
Brake Fluid and Seals
Brake fluid looking a bit dirty? Probably time for a change. Even when carefully following the manufacturer's recommendation, the brake fluid needs far less changes when compared to the oil or other liquids that keep your dirt bike in tip top shape. For the most part, as long as levels remain in the acceptable range, it doesn't leak and the master cylinder works efficiently you can leave the brake fluid alone. But it degrades over time with heat and aggressive riding, absorbs moisture and also gets dirty. If your brakes feel squishy check the fluid. And remember to use DOT 4 when topping off or replacing.
Speaking of the master cylinder, yes another seal to worry about. A bad seal results in brake fluid leaking or prevents the plunger/piston from working correctly. A total master cylinder failure results in complete brake loss. Consequently, if you have an older bike and have been riding with the angels, rebuild the master cylinder, bleed the brakes and add new fluid.
Adhering to the manufacturer's suggested service intervals prevents many breakdowns and failures and incorporating a preventative maintenance routine keeps your bike "young" and often helps eliminate the older bike problems. On the other hand, neglecting routine maintenance makes the list above a much longer undertaking.
For a complete rebuild of an older dirt bike, check out "How To Make Your Old Dirt Bike New Again".
Written By: AndrewT