Investing in a dirt bike is like adding a high maintenance and needy friend into your life. But the reward of giving all that love and attention to this seemingly impoverished piece of machinery is unequaled.
Unlike today's modern cars, where you can ride for thousands of miles (sometimes 10,000 miles without changing even the oil!) and do little in the way of maintenance, 4-stroke dirt bikes require constant maintenance. Those thinking of taking on the joy of this sport should first know that after every ride some type of maintenance is required to ensure the longevity of the bike.
Maintenance, over time, becomes as much of the dirt bike owning experience as the ride. Many riders embrace this aspect of ownership others find the detail work a hassle. Regardless, we can all agree we'd much rather be out riding then stuck in a garage fixing a broken down machine. The best way to ensure your dirt bike operates effectively and starts every time is to take the time and conduct routine maintenance.
This guide covers the routine maintenance needs of the 4-stroke dirt bike to help you move quickly and efficiently through the process so you can get out of the garage and back on the track or trail. We cover the following sections:
- Cleaning and Lubing Cables
- Chain and Sprocket Care
- Air Filter Maintenance
- Pipe Maintenance
- Spoke Maintenance and Tightening
- Carburetor Care and Maintenance
- Additional Maintenance Suggestions
Before we begin: Start with a clean bike.
Cleaning and Lubing Cables
Cables represent the lifeline to most of the controls on your dirt bike. Throttle and clutch cables and the front brake line all need to be cleaned after a ride and routinely lubricated. For more information on cables, check out our Dirt Bike Handlebars and Controls Guide.
Carefully disconnect the cables from the perch and lever (for throttle cables disconnect the carburetor end) to clean any build-up around the connections. Add some lubrication, reconnect and tighten the connections. The lubrication not only protects the cables from wear and tear but acts as a barrier to dust and debris.
Chain and Sprocket Care
Never ride with dry chains and sprockets. A lubricated chain is a happy chain that rewards you with long life. Always clean the chains and sprockets after a ride and then follow that with good dousing of lubrication. In the event you see significant wear and tear on your chain OR sprockets, replace the whole drive train. See our Ultimate Dirt Bike Gearing Guide for additional information.
An important aspect to chain care is ensuring your chain is at the correct adjustment. Too loose? Too tight? Best case you bust your chain. Worst case the chain snaps, whips off and breaks your engine case or gives you a permanent chain tattoo. An easy way to determine correct chain length is to stick two fingers between the chain and chain guide - if the chain presses against your fingers its tightened enough.
Keeping the chain adjusted correctly helps extend the life of the chain and sprockets, transmission seals and bearings, wheel bearings, hubs and even the wheels to some extent.
Air Filter Maintenance
A dirty air filter sucks the life out of your engine so it's crucial to ensure the air filter and properly cleaned and maintained. It's a dirty job for sure but imagine if all that dirt got inside the engine! Clean your air filter thoroughly with cleaner, dry it well and then soak it with air filter oil. Let it get real tacky before you install it and ride again.
Air Filter Oil
The obvious here is to clean the outside of your pipe to prevent rust and corrosion. While you're back there, check out the muffler packing. In a 4-stroke the muffler packing can get compressed and once it gets to this point, it is for the most part, ineffective. Replace the packing once it gets to this stage though the product is not all that expensive so it's not a bad idea to replace it, if budget allows, routinely.
Dirt Bike Exhaust Packing
4-stroke Exhaust Packing
Spoke Maintenance and Tightening
First get yourself a spoke wrench if you don't already have one. The key to tightening your spokes starts with patience. You can't just haphazardly start tightening your spokes; there's a technique involved to ensure the best outcome.
We suggest tightening every third spoke which means you'll go around your tire a minimum of three times. Don't over tighten either. Tighten every third spoke until a light snug is reached and if necessary go back around checking every third spoke again. Check out our How to: Wheel Truing and Lacing video and our Dirt Bike Tires & Wheels Explained guide for additional tips.
Carburetor Care and Maintenance
If left un-checked the carburetor is the most likely part of your machine to fail first. Even not riding is cause to check on the carburetor’s condition as evaporated gas leaves residue that can plug your jets. Routine maintenance also determines whether you need to jet your carburetor. Check out our Simple Guide to Jetting Your Carb.
There's a reason why you have fenders, mud guards and side paneling. Plastics protect you and your bike from dirt, debris and roost kicked up by your own riding and others around you. Plus you'll be thankful for them in the event of a crash.
If you're like most riders, you can't stand un-kept plastic that looks dull and faded well past its prime. Regular cleaning and upkeep prevents plastic from fading and looking old. Check out our guide on How to Make You Dirt Bike Plastic Look New Again.
It may surprise you but coolant, especially in the 4-stroke, is not something you can simply add and forget about. Keeping the 4-stroke engine running cool is a high priority as the smaller parts inside a small box, if you will, can overheat fast and ruin your day of fun on the track quite quickly. Four-stroke coolant is specially formulated to drastically reduce engine temperature and keep those vital engine parts from overheating and breaking down.
Four-stroke engines works hard, therefore coolant works hard. It's imperative to schedule regular changes so you have fresh coolant to take on the hardest riding. This is even more important in the summer months and double important if you ride in sand dunes. In fact, some coolant is specially designed for sand dune running. Check out our How to Prep Your Dirt Bike for the Sand Dunes guide.
Additional Maintenance Suggestions
Keep an eye on your transmission or gear oil. This oil needs changing often and when in doubt it's always best to ride with fresh oil. See our guide to Dirt Bike Oils for more information. A great way to determine maintenance intervals is to invest in an hour meter so you know how much time has passed since the last time you rebuilt the top end of your machine. Check your owner's manual on recommended maintenance intervals.
The clutch in a 4-stroke does not wear out as fast as the 2-stroke clutch however that doesn't mean you can let this one slip by as some riders, inclduing you, may ride the clutch hard. Taking care of the clutch cable (see above) is the first place to start. Check your service manual for how often to check your clutch. To see a detailed look at checking your clutch and inspecting the clutch plates, check out our Rockstar Energy How To: The Clutch video.
See our guide on bleeding your dirt bike brakes. Bleeding your brakes is a part of maintenance however you won't need to address it as often as other needs and keeping an eye on the brake fluid level is your primary concern.
Finally, valve adjustment and service is best left to a professional mechanic. Check your owner's manual for the recommended service intervals and use an hour meter to stay on top of it.
Written By: AndrewT