Troubleshooting
Dirt Bike Won't Start? A Step-By-Step Troubleshooting Guide
Dirt bike won't start? Work through fuel, air, spark and compression with checks from KTM, Yamaha and Honda manuals, plus 2-stroke, hot start, EFI fixes.
MotoMind Blog / Videos & guides
UNDERSTAND IT.
LOOK AFTER IT.
Search dirt bike videos, explainers and interactive service guides. Filter by topic or format to find the right maintenance job or understand how your bike works.
Maintenance
How Often To Change Dirt Bike Oil: Real Intervals From Owner's Manuals
How often to change dirt bike oil, by model: 4-stroke engine oil and 2-stroke gear oil intervals, capacities and specs from KTM, Yamaha, Honda and more.
Maintenance
How To Clean A Dirt Bike Air Filter: Step By Step From The Manuals
How to clean a dirt bike air filter the way KTM, Yamaha and Honda say to: cleaner, filter oil, sealing grease, OEM intervals and dust and sand tips.
Maintenance
Dirt Bike Chain Slack And Maintenance: OEM Specs, Adjustment And Sprocket Wear
Dirt bike chain slack specs from KTM, Husqvarna, GASGAS, Yamaha and Honda manuals, how to measure and adjust it, plus chain wear and sprocket replacement.
Troubleshooting
Dirt Bike Bearing Maintenance: Wheels, Steering Head, Swingarm And Linkage
Why dirt bike wheel, steering head, swingarm and linkage bearings fail, how to check for play and notches, KTM torque specs and OEM grease intervals.
Troubleshooting
Dirt Bike Clutch Slipping Or Dragging: Causes, Checks And Fixes
Why a dirt bike clutch slips or drags, how to check free play, oil, plates and springs against OEM limits, and what to replace. YZ250F and KTM specs.
Troubleshooting
Dirt Bike Fork Seal Leaking? Why It Happens And How To Fix It
Why dirt bike fork seals leak, how to clean them with a seal tool, when to replace them, plus fork oil specs and intervals from KTM, Honda and Yamaha.
Troubleshooting
Dirt Bike Fouled Spark Plug: Why It Happens And How To Read It
Why dirt bike spark plugs foul, how to read the tip, heat range explained, and the exact NGK plug, gap and torque from KTM, Honda and Yamaha manuals.
Troubleshooting
Dirt Bike Tire Pressure, Pinch Flats And Rim Locks
Dirt bike tire pressure from KTM and Honda manuals, why low psi causes pinch flats, rim lock and spoke torque, and how often to check them.
How it works
EFI vs Carburetor On A Dirt Bike
How a dirt bike carburetor and fuel injection each meter fuel, why carbs run rich at altitude, what EFI adds, and how maintenance differs, with OEM specs.
How it works
How A Dirt Bike Carburetor Works
See how a dirt bike carburetor works: float bowl, pilot jet, slide cutaway, jet needle and main jet, with an animated section view and real KTM specs.
How it works
How A Dirt Bike Clutch And Transmission Work
Animated section views of a wet multi-plate clutch and a constant-mesh dog gearbox, with real YZ250F, YZ450F and KTM specs, ratios and oil rules.
How it works
How A Four-Stroke Dirt Bike Engine Works
See how a four-stroke dirt bike engine works: cams, buckets, valves and the cam chain, animated through intake, compression, power and exhaust.
How it works
How A Two-Stroke Dirt Bike Engine Works
See how a two-stroke dirt bike engine works with an animated section view: reed valve, ports, transfer, power stroke, premix and why top ends wear.
How it works
How A Two-Stroke Expansion Chamber Works
How a two-stroke expansion chamber uses pressure waves to pull charge in and plug the exhaust port, with Jennings’ pipe math and an rpm timing figure.
How it works
How A Two-Stroke Power Valve Works
How a two-stroke power valve changes exhaust port height with rpm, what it does to port timing, why carbon jams it, and the KTM service steps and torque specs.
How it works
How Dirt Bike Suspension Works
How dirt bike forks and shocks work, animated: springs, shim stacks, clickers, rebound, sag geometry and linkage, with real KTM, Honda and Yamaha specs.
Troubleshooting
How To Bleed Dirt Bike Brakes (And How Hydraulic Brakes Work)
Fix a spongy dirt bike brake lever. See how hydraulic brakes work, why air and wet fluid go soft, and bleed them step by step with KTM and Honda specs.
Troubleshooting
How To Check Dirt Bike Valve Clearance (And Shim It)
Why four-stroke dirt bike valves tighten, the symptoms, how to measure clearance at TDC, KTM and Honda specs, and the shim formula with a free calculator.
Troubleshooting
How To Clean A Dirt Bike Carburetor And Unclog The Pilot Jet
Bike only runs on choke or will not idle? How to clean a dirt bike carburetor, clear a varnished pilot jet, reset the idle, and stop old fuel clogging it.
Maintenance
How To Repack A Dirt Bike Silencer
How to repack a dirt bike silencer: why packing burns out, the signs, KTM step-by-step with 7 Nm and 10 Nm torque specs, and OEM vs aftermarket intervals.
How it works
Steel vs Aluminum Dirt Bike Frames: Stiffness, Flex and Weight
Why KTM builds chromoly steel frames and Honda and Yamaha use aluminum beams, with the math, the 1997 CR250 story and frame checks.
Troubleshooting
Why Your Dirt Bike Overheats And How The Cooling System Works
Why a dirt bike overheats or boils over: how the pump, radiators and pressure cap work, boiling point math, and KTM, Yamaha and Honda coolant specs.
Maintenance
Dirt Bike Air Filter Service, Animated
An animated ten-step air filter service: wash the foam, press it out, oil it in a bag, grease the rim and lock it in place without gaps.
Maintenance
Dirt Bike Bolt, Controls and Skid Plate Check
Walk around the bolts that loosen most on a dirt bike: axles, clamps, engine mounts, disc, caliper and sprocket bolts, levers, cables and skid plate.
Maintenance
Dirt Bike Bottom End Rebuild Signs and Checks
The signs a dirt bike bottom end needs a rebuild, the hours manuals set, how to check rod play and crank seals, and what to ask the shop.
Maintenance
Dirt Bike Brake Fluid Flush, Animated
An animated brake fluid flush: fit the bleed hose, squeeze, crack and close the bleeder, keep the reservoir topped up and stop when it runs clean.
Maintenance
Dirt Bike Chain Check, Adjust and Lube, Animated
An animated chain routine: look for stiff links and hooked teeth, measure slack and wear, adjust both sides evenly, torque the axle and lube it.
Maintenance
Dirt Bike Fork Seal Check, Animated
An animated fork seal check: bleed the legs, find the real leak, clean behind the wiper and under the lip, and check the tubes for nicks.
Maintenance
Dirt Bike Sag Check, Animated
An animated sag check: measure A, B and C, compare rider and static sag with your spec, set preload and decide if the spring suits your weight.
Maintenance
Dirt Bike Silencer Repack, Animated
An animated silencer repack: end cap off, inner tube out, wrap new packing, O-ring on and screws torqued, plus a check of the pipe while it is off.
Maintenance
Dirt Bike Tire Pressure and Tread Check, Animated
An animated pre-ride tire check: set pressure cold with a low-range gauge, look at the valve stem and rim lock, and read the knobs and sidewalls.
Maintenance
Dirt Bike Valve Clearance Check, Animated
An animated walk-through of a four-stroke valve clearance check: find TDC, measure every valve, write it down and work out the new shim size.
Maintenance
Electric Dirt Bike Battery, Charge Port and Wiring Care
Owner checks for an electric dirt bike: charge it the right way, inspect the port and cable, keep software current, check motor cooling and store it.
Maintenance
How to Adjust Dirt Bike Steering Head Bearings
Check a dirt bike steering head for play and notches, set the bearing preload, torque the clamps and know when to grease or replace the bearings.
Maintenance
How to Change a Dirt Bike Spark Plug
Pull, read, gap and torque a dirt bike spark plug in eight animated steps, with the plug and gap specs for KTM, Honda and Yamaha models.
Maintenance
How to Change Dirt Bike Brake Pads
Push the pistons back, pull the pad pin, fit new pads as a pair, torque the caliper and pump the lever firm before you bed them in. Animated steps.
Maintenance
How to Change Dirt Bike Coolant
Check dirt bike coolant cold, inspect hoses and radiators, then drain, flush, refill with the right mix and bleed out the air. Ten animated steps.
Maintenance
How to Change Dirt Bike Fork Oil
Drain and refill the outer chamber of a dirt bike fork by volume, refit and torque the clamps, and know when the cartridge is a job for a shop.
Maintenance
How to Change Dirt Bike Oil and the Oil Filter
Change four-stroke dirt bike oil and the filter in nine animated steps: drain, read the magnet, clean the screen, refill by volume and check the level.
Maintenance
How to Change Two-Stroke Gear Oil
Drain and refill two-stroke dirt bike transmission oil with the measured amount, a new crush washer and the right drain plug torque, shown step by step.
Maintenance
How to Check a Dirt Bike Cam Chain
Listen for a worn cam chain, check the timing marks, tensioner, sprockets and guides, and know the replacement interval for race four-strokes.
Maintenance
How to Check and Replace Dirt Bike Wheel Bearings
Rock and spin the wheel to find a worn bearing, then pull the seals and bearings, press new ones in on the outer race and torque the axle.
Maintenance
How to Check Dirt Bike Spoke Tension
Tap test every spoke to find the loose one, tighten in small turns with a spoke wrench, work around the wheel in a pattern and check rim runout.
Maintenance
How to Check Two-Stroke Reed Valves
Get to the reed block, light test the petals for gaps, chips and cracks, check the stoppers, seat and gasket, then refit it to torque.
Maintenance
How to Clean a Two-Stroke Power Valve
Take the cover off, pull the power valve, scrape off the carbon and check it moves freely before you refit and torque it. Animated, step by step.
Maintenance
How to Grease Dirt Bike Linkage and Swingarm Bearings
Check the swingarm and shock linkage for play, strip and clean the needle bearings, regrease and torque every pivot bolt back to spec.
Maintenance
How to Inspect Dirt Bike Brakes
A full dirt bike brake check: lever feel, fluid level and age, pad lining, disc thickness and runout, hoses and fasteners, with OEM limits.
Maintenance
How to Rebuild a Two-Stroke Top End
Rebuild a two-stroke dirt bike top end from pipe off to break-in: measure the piston and bore, check ring gap and torque the base nuts and head.
Maintenance
How to Replace a Dirt Bike Chain and Sprockets
Swap a dirt bike chain and both sprockets as a set: break the nuts loose, size the new chain, fit the master link clip and set slack and torque.
Maintenance
How to Wash a Dirt Bike and Inspect It
Plug the exhaust, cover the intake, keep the pressure washer off seals and bearings, then dry, lube and inspect the bike while it is clean.
Maintenance
When to Service a Dirt Bike Shock
Know when a dirt bike shock service is due, spot the signs, check the shaft, seal, mounts and bearings, and tell the suspension shop what you need.
Buying & ownership
2-Stroke vs 4-Stroke vs Electric Dirt Bike
Compare 2-stroke, 4-stroke, and electric dirt bikes across power delivery, maintenance, rider fatigue, noise, and ownership costs.
How it works
Dirt Bike Gearing Explained: Sprockets, Ratios And Speed Per Gear
How dirt bike gearing works: primary drive, gearbox and sprockets, why one front tooth equals about 3.6 rear teeth, and speed per gear from OEM specs.
Troubleshooting
Dirt Bike Jetting Guide: Why It Bogs At Altitude And How To Fix It
Why a carbureted dirt bike runs rich and bogs at altitude or in heat, how to read the plug, which jet controls which throttle range, and how to re-jet.
How it works
How Electric Dirt Bikes Work, From Battery To Rear Wheel
How do electric dirt bikes work? Battery, inverter and motor explained with an animated power path, plus why there is no gearbox, regen and heat limits.
History
How The Yamaha YZ400F Brought Four-Strokes Back To Motocross
YZ400F history and specs: why four-strokes lost to two-strokes, the AMA 550 cc rule, Doug Henry’s 1997 Las Vegas win and the first four-stroke title.
History
The History Of Dirt Bikes, From 1950s Scramblers To Electric
How dirt bikes evolved from 1950s British scramblers to electric motocrossers: two-strokes, single shocks, water cooling, aluminum frames and EFI.
History
The History Of Motocross And Supercross
The history of motocross and supercross: the 1924 scramble, the first world titles, the 1972 LA Coliseum race, AMA Supercross and the 2023 SMX playoffs.
Maintenance
When To Rebuild A Dirt Bike Top End: Hours, Symptoms And Testing
When to rebuild a dirt bike top end: OEM piston hours for 2-stroke and 4-stroke models, worn engine symptoms, compression and leak-down testing.
Maintenance
How To Adjust Dirt Bike Chain Slack
Adjust dirt bike chain slack step by step: loosen the axle nut, turn both adjusters equally, measure 58 to 61 mm (KTM) and torque the axle nut to 80 Nm.
Maintenance
How To Check Dirt Bike Valve Clearance
Check four-stroke dirt bike valve clearance step by step: find TDC on compression, measure with feeler gauges, compare to spec and work out the new shim.
Maintenance
How To Clean And Oil A Dirt Bike Air Filter
Clean and oil a foam dirt bike air filter step by step, with a cut-away that shows how oiled foam and a greased rim stop dust before it reaches the engine.
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