Choosing and Maintaining the Right MX Bike

It is very common among riders to consider our bikes to be the same each time we are about to ride, but we should know that parts wear out and many can and do break due to stress. We should always give each bike a basic check up before each event. Actually it is a very good habit to inspect our bike before each moto. It is not uncommon for parts to break or need replaced before the end of the moto.

In this section we’ll go over some of the most important things to check each time before you go to the track. It’s important to remember that all bikes are different. Some bikes are more prone to certain types of failures. For instance: certain 50cc bikes are known for burning up stators, while many of the four-stroke engines are more known for excessive valve wear and failure. Also the older steel framed full-sized bikes as well as some of the newer small ones are known for frame stress cracking. Know your bike and look for the types of failures that are common to them. This will help you avoid major failures on the track that could result in injury.

Make sure all the plastic on your bike is in good shape. Check for broken or jagged edges that could cause harm to yourself or another rider. If you can’t afford to replace a broken plastic, you can trim and grind the sharp edges off.

Be sure you can reach all the controls comfortably while sitting and standing. This includes the clutch, front brake, gear shifter, and rear brake pedal. In addition to proper positioning, be sure your controls are working properly. Shifters and levers should not have sharp broken ends, or be loose and floppy – instead they should all be kept tightly snug. Also you should check your clutch, brake and throttle cables for any frayed ends or kinks.

Bolts, Nuts and Fasteners
As a responsible rider you should go over your bike from time to time and check that all the bolts are tight.

Plastic Bolts (shrouds, fenders, seat, number plates) – Seat bolts tend to vibrate out because they are taken in and out so much

Controls/Handlebars – These items see lots of stress. Check them regularly.

Triple Clamps – Top and bottom triple clamp bolts are very important. Be sure they are torque to manufacturers’ specs before riding your bike. The top nut on the stem will also vibrate loose at times. A regular check up will catch these.

Axles – Front and rear axles are also very important items to check regularly. These can get left loose during wheel changes. While you are there check the pinch bolts on the axle and the condition of your brake pads. If your bike comes from the factory with cotter pins to retain the front or rear axle nut be sure you install new cotters pins are any wheel maintenance. Without a cotter pin, there is nothing to prevent these “castle” nuts from coming loose.

Motor Mounts – Motor mounts are an integral part of the mechanical integrity of a motorcycle. Loose motor mounts can lead to frame failures, chain drive failures, and engine failures to name a few. Check the motor mounting bolts and the tabs they connect to frequently.

Sprockets/Spokes – Some bikes, especially the big four-strokes, tend to work spokes and rear sprocket bolts loose. Keep a close eye on these items. Once a week, check sprocket bolts and spokes. If you don’t know how to tighten spokes, see a qualified mechanic. If this is done incorrectly it can lead to warped wheels. If your sprocket bolts tend to come loose regularly replace the locking nuts with new ones. These lock nuts are only good for about three or four uses before they lose their locking ability. New bikes tend to need more attention in these areas until the spokes and sprocket bolts “break-in”.

Rear Suspension Linkage – While not common these bolts can also come loose. It’s a good idea to grease all your suspension bearings once or twice a year. This will help overall suspension performance while also greatly increasing the life span of these parts. Frequently check your linkage bolts to insure they are properly tightened.

Is your engine running properly? If your bike is running poorly you should have it repaired before venturing onto a motocross track. Simple things like jetting, air filters, and spark plugs can cause huge crashes if not maintained properly. Follow the manufacturer’s recommendations on how often you should rebuild or perform routine maintenance on your engine. There are many factors that influence engine performance and therefore rider safety. Make sure you start each day with a clean air filter. Some dusty days will require an air filter change during the day. Change your engine oil often and use a good quality gear lube. For four-strokes, keep the valves checked and adjusted. For two-strokes, use good quality premix and good fuel. Keep a check on the spark plug condition as two-strokes are a little more particular about their jetting.

Today’s stock suspension components are excellent on motocross bikes. Be sure your bike is set up for your weight and skill, and adjusted for the track conditions. Poorly setup suspension components will not only cause you to fatigue quickly, they can also cause you to unexpectedly lose control. Refer to the chassis section above for tips on checking bolts on your front and rear suspension. If you are unsure how to perform adjustments and/or suspension maintenance, seek help from a qualified technician.

Be sure your tires have good tread, have no visible cracks and are inflated to the proper pressure. Worn or improperly inflated tires can cause loss of traction that can result in loss of control. You should always check your tire pressure before every race.

Choosing the right bike
Always choose the right machinery for your rider’s size, weight, skill level and the intended use of the bike. Riders on small, recreational machinery like the CRF50, 70, 80,100, TTR125s, and KLX110s should not attempt the larger combination jumps like doubles and tabletops. These types of bikes are not intended for such use and may react in unexpected ways. Landing from large jumps on a bike that lacks in the suspension area could cause a rider to lose control and crash. In a worst-case situation frames and wheels can break. When a rider in these entry-level classes reaches the point where he or she is ready to attempt larger or combination jumps parents should consider moving them up to a suitable motocross specific bike that will function properly under these more demanding conditions. Conversely, a rider should not be put on machinery that is too big or too powerful for their size and skill level.

A rider should be able to pick his/her bike up, start it, and perform a race start–unassisted. In addition, the rider should be able to exhibit full control on motocross obstacles while riding to his/her potential. This is often a very subjective decision for a rider and/or parent. Riders should spend a reasonable amount of time getting comfortable on any new bike before attempting to race it for the first time. Owner’s manuals have a wealth of information about Do’s and Don’ts of racing machinery and how to maintain them for proper function.

Another great place to find this information is by interacting with others at the tracks. You or your child’s safety is the most important aspect of any day at the track. Use all these resources to their fullest potential and always be aware of your surroundings. Motocross is a very dangerous sport. Do everything you to limit the risks. Follow a sound bike maintenance routine, invest in and wearing proper safety gear, and exercise sound judgment while riding. These simple measures can significantly reduce the number of variables that often lead to injuries.

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