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Troubleshooting Guide - KTM 300 XC-W & Husqvarna TE 300

Comprehensive troubleshooting guide for common issues with KTM 300 XC-W and Husqvarna TE 300 2-stroke enduro bikes.

Troubleshooting Guide

Engine Won’t Start

No Spark Issues

Symptoms: Engine turns over but won’t fire, no spark at plug

Check Order:

  1. Kill switch - Ensure it’s in RUN position
  2. Spark plug - Remove and inspect
    • Wet: Flooded, let dry
    • Dry: Fuel issue
    • Fouled: Replace immediately
  3. Plug gap - Should be 0.5-0.6mm
  4. CDI ground - Clean connection at frame
  5. Stator resistance - 2019-2021: 750-950 ohms, 2022+: 800-1000 ohms
  6. CDI unit - Swap with known good unit

Common Fix: Replace spark plug (NGK BR8ES or BR9ES)

Fuel Delivery Problems

TBI Models (2023+):

  1. Fuel pump prime - Turn key on, listen for pump
  2. Fuel pressure - Should be 58 PSI
  3. Injector click - Audible when cranking
  4. TPS voltage - 0.6V closed, 4.5V WOT
  5. Error codes - Check dash display

Carbureted Models (2019-2022):

  1. Fuel on - Petcock in ON position
  2. Float bowl - Drain and check for debris
  3. Pilot jet - Remove and clean (#40 stock)
  4. Choke operation - Pull fully for cold start
  5. Reed valve - Inspect for cracks/chips

Compression Issues

Quick Test: Hold kick starter at TDC

  • Good: Strong resistance, holds position
  • Bad: Kicks through easily

Detailed Check:

  1. Compression test - Should be 170-190 PSI
  2. Power valve - Check operation and cleaning
  3. Cylinder/piston - Inspect through exhaust port
  4. Head gasket - Look for coolant in cylinder
  5. KIPS adjustment - Critical on KTM models

Running Issues

Bike Bogs or Hesitates

Low Speed Bog:

  • Pilot jet clogged (clean or replace)
  • Air screw adjustment (1.5-2 turns out)
  • Throttle cable slack (2-3mm free play)
  • Power valve sticking (clean and inspect)
  • Reeds cracked (replace if damaged)

Mid-Range Bog:

  • Needle position (raise clip for richer)
  • Main jet too small (stock #175)
  • Exhaust packed with carbon
  • Air filter dirty or over-oiled
  • Altitude changes (rejet required)

High-Speed Issues:

  • Main jet size incorrect
  • Exhaust restriction
  • CDI limiting RPM
  • Fuel quality (use 91+ octane)

Overheating Problems

Temperature Range:

  • Normal: 160-180°F
  • Concern: 190-200°F
  • Danger: Above 210°F

Causes and Fixes:

  1. Coolant level - Check when cold
  2. Radiator blockage - Clean fins carefully
  3. Water pump - Check impeller condition
  4. Thermostat - Test in hot water
  5. Head gasket - Compression test
  6. Jetting - Lean condition causes heat
  7. Timing - Retarded timing runs hot
  8. Utah altitude - Requires richer jetting

Hard Starting When Hot

Common Causes:

  1. Vapor lock (TBI models) - Let cool 5 minutes
  2. Flooded (carb models) - WOT and kick
  3. Heat soak - Fuel boiling in carb
  4. Compression - Too high when hot
  5. Ignition timing - Advances with heat

Solutions:

  • Install heat shield on exhaust
  • Use race fuel in summer
  • Adjust float level slightly lower
  • Check valve clearances
  • Verify CDI mapping

Suspension Problems

Fork Issues

Harsh Feel:

  • Oil level too high (110mm air gap)
  • Wrong oil weight (use SAE 5)
  • Valving too stiff
  • Worn bushings
  • Bent tubes

Soft/Diving:

  • Oil level too low
  • Worn seals leaking
  • Springs too soft
  • Cavitation in oil
  • Broken shim

Stiction/Binding:

  • Dirty seals
  • Misaligned forks
  • Bent tubes
  • Worn bushings
  • Wrong oil viscosity

Shock Problems

No Damping:

  • Blown seal
  • No nitrogen charge
  • Broken shaft
  • Bypassed piston
  • Oil contamination

Harsh Ride:

  • Too much preload
  • Wrong spring rate
  • Valving issues
  • Linkage binding
  • Worn spherical bearings

Clutch and Transmission

Clutch Slipping

Diagnosis: Revs increase without acceleration

Fixes:

  1. Adjustment - 2-3mm free play at lever
  2. Oil type - Use JASO MA2 rated only
  3. Plates - Measure thickness (minimums below)
  4. Springs - Check free length
  5. Basket - Inspect for notching

Specifications:

  • Friction plates: 2.92-3.08mm
  • Steel plates: 1.5mm minimum
  • Spring length: 36.5mm minimum

Clutch Dragging

Symptoms: Hard to shift, creeps in gear

Solutions:

  1. Cable adjustment - Too tight
  2. Warped plates - Replace steel plates
  3. Swollen fibers - Wrong oil used
  4. Notched basket - File smooth or replace
  5. Bent pushrod - Roll on flat surface

Transmission Issues

Hard Shifting:

  • Clutch not disengaging fully
  • Bent shift fork
  • Worn dogs on gears
  • Detent spring weak
  • Linkage adjustment

Jumping Out of Gear:

  • Worn gear dogs
  • Bent shift fork
  • Weak detent spring
  • Worn shift drum
  • Improper shimming

Electrical Problems

Charging System

No Lights/Weak Lights:

  1. Test stator output: AC voltage while running
  2. Regulator/rectifier: Convert to DC properly
  3. Connections: Clean all grounds
  4. Wire harness: Check for chafing
  5. LED conversion: Reduces load significantly

Battery Not Charging (E-start models):

  • Stator output: 13.5-14.5V at 5000 RPM
  • Regulator test: No AC on DC side
  • Battery condition: Load test
  • Parasitic draw: Under 0.05A

Starting System

E-Start Won’t Engage:

  1. Battery voltage (12.6V minimum)
  2. Starter relay click
  3. Starter motor brushes
  4. Bendix engagement
  5. Compression release operation

Brake Problems

Spongy Brakes

Front Brake:

  • Air in system - Bleed properly
  • Worn pads - Replace at 1mm
  • Warped rotor - Check runout
  • Master cylinder - Rebuild kit
  • Contaminated fluid - Flush system

Rear Brake:

  • Same as front plus:
  • Pedal adjustment
  • Return spring tension
  • Clevis pin wear

Brake Drag

Causes:

  • Piston not retracting
  • Contaminated fluid
  • Collapsed brake line
  • Warped rotor
  • Caliper alignment

Common Trail Fixes

Emergency Repairs

No Spark:

  • Clean plug with gasoline
  • Dry thoroughly
  • Check plug cap connection
  • Bypass kill switch

Fuel Issues:

  • Prime TBI manually
  • Clean pilot jet with wire
  • Blow through fuel line
  • Check vent hose routing

Cooling Problems:

  • Add water (emergency only)
  • Remove thermostat
  • Clear radiator fins
  • Reduce pace

Clutch Problems:

  • Adjust cable fully out
  • Remove one steel plate
  • Use heavier oil temporarily
  • Baby the clutch

Tool Kit Essentials

Must Have:

  • 8, 10, 12, 13mm T-handles
  • Spark plug socket
  • Tire irons (3)
  • Chain breaker/riveter
  • Duct tape
  • Zip ties
  • Safety wire

Nice to Have:

  • Clutch cable
  • Spark plug
  • Master link
  • Brake pads
  • Radiator stop leak
  • JB Weld
  • Electrical tape

Diagnostic Flowcharts

No Start Flowchart

Turn Over? → No → Check kickstarter
    ↓ Yes
Spark? → No → Check electrical
    ↓ Yes
Fuel? → No → Check delivery
    ↓ Yes
Compression? → No → Major issue
    ↓ Yes
Timing/Jetting Issue

Running Rough Flowchart

When? → Cold only → Pilot circuit
      → Hot only → Heat/vapor issue
      → All temps → Continue
           ↓
RPM? → Idle → Pilot jet/air screw
     → Mid → Needle/slide
     → High → Main jet
           ↓
Check air filter, exhaust, reeds

When to Seek Professional Help

Call Mountain Goat Sports when:

  • Compression below 150 PSI
  • Transmission jumping gears
  • Major electrical issues
  • Suspension internals needed
  • Engine rebuild required
  • Diagnostics exhausted

Our diagnostic service includes:

  • Full compression test
  • Leak-down test
  • Electrical system check
  • Suspension evaluation
  • Written estimate
  • Honest recommendations

Remember: A correctly running KTM 300 XC-W or Husqvarna TE 300 should start within 3 kicks when cold, idle smoothly, and pull strongly through the entire RPM range without hesitation.

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