KTM 350 SX-F 2021 User Manual (English)

Questions and Answers:

A
Amanda PopeAug 3, 2025
What to do if my KTM Motorcycle engine does not turn when the start button is pressed?
- E
  Emily GonzalezAug 3, 2025
  If your KTM Motorcycle engine doesn't turn over when you press the start button, there could be several reasons. It could be due to an operating error, so make sure you are following the correct start procedure. The 12V battery might be discharged, so you should charge it, check the charging voltage, open-circuit current, and the alternator's stator winding. Also, the main fuse could be blown, in which case you should change it. Finally, the starter relay or the starter motor itself could be defective, so these should be checked.
C
carrie30Aug 7, 2025
What to do if my KTM 350 SX-F 2021 engine turns but does not start?
- F
  fspencerAug 7, 2025
  If your KTM Motorcycle engine turns but doesn't start, several factors could be the cause. First, check if the quick release coupling is properly joined. A clogged fuel screen in the quick release coupling could also be the problem, so you may need to replace it. Incorrect idle speed can prevent starting, so adjust it accordingly. Also, inspect the spark plug; if it's oily or wet, clean and dry it, or replace it if needed. Ensure the spark plug gap is correct, with a guideline of 0.8 mm (0.031 in). A frayed short-circuit cable or faulty switch-off button can cause this issue, so check the wiring harness and electrical system. Lastly, a malfunction in the electronic fuel injection could be the cause, requiring you to read out the fault memory using the KTM diagnostics tool.
H
Harry MunozAug 12, 2025
Why is my KTM 350 SX-F 2021 consuming so much oil?
- K
  Keith MarshallAug 12, 2025
  High oil consumption in your KTM Motorcycle can be attributed to several factors. A bent engine vent hose can cause increased oil usage, so ensure the vent hose is routed without bends, or replace it if necessary. An excessively high engine oil level can also lead to higher consumption, so check and correct the engine oil level. Using engine oil that is too thin (low viscosity) can also contribute to this issue, so change the engine oil and oil filter, and clean the oil screen. Lastly, worn piston or cylinder components can increase oil consumption, so measure the piston/cylinder mounting clearance.
P
Philip DavisAug 16, 2025
Why does my KTM Motorcycle engine overheat?
- N
  nathannorrisAug 16, 2025
  Your KTM Motorcycle engine might be overheating due to several reasons. There might be too little coolant in the cooling system, so check for leaks and verify the coolant level. Insufficient airflow can also cause overheating, so switch off the engine when standing. Dirty radiator fins can restrict cooling, so clean them. Foam formation in the cooling system can also lead to overheating, so drain and refill the coolant. Finally, a bent radiator hose can restrict coolant flow, so replace it if necessary.
J
John MartinezAug 20, 2025
Why does my KTM 350 SX-F 2021 Motorcycle have too little power?
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  Jeremy WilliamsAug 20, 2025
  If your KTM Motorcycle has too little power, several issues could be responsible. A very dirty air filter can restrict airflow, so clean the air filter and air filter box. A dirty fuel filter can also reduce power, so replace it. A malfunction in the electronic fuel injection could be the cause, requiring you to read out the fault memory using the KTM diagnostics tool. Check the exhaust system for leaks or deformation, and consider changing the glass fiber yarn filling in the main silencer. Lastly, insufficient valve clearance can affect power, so adjust the valve clearance.

KTM 350 SX-F 2021 Specifications

General

Displacement	349.7 cc
Bore x Stroke	88 mm x 57.5 mm
Transmission	5-speed
Seat Height	950 mm
Ignition	Keihin EMS
Final Drive	Chain
Front Suspension	WP XACT-USD, Ø 48 mm
Rear Suspension	WP XACT Monoshock with Linkage
Starter	Electric starter
Ground Clearance	370 mm
Engine Type	Single Cylinder, 4-Stroke Engine
Fuel System	Electronic fuel injection
Cooling System	Liquid-cooled
Front Brake	Disc brake, Ø 260 mm
Rear Brake	Disc brake, Ø 220 mm
Tank Capacity	7 liters
Frame Type	Chromium-molybdenum frame