KTM 2012 250 SX-F Operating instructions

In-Depth Engine and Fuel

System Maintenance and

Repair Manual

2012 KTM 250 SX-F

Jeremy Jonas

December 2, 2013

Denton, TX

iii

Table of Contents

Table of Contents................................................ ii

Introduction ....................................................... 1

Troubleshooting.................................................. 3

Fuel System .................................................... 3

Engine ............................................................ 4

Common Maintenance and Repairs: Fuel System .... 5

Replacing the Fuel Filter.................................... 5

Changing the Fuel Injector ................................ 7

Replacing the ECU...........................................8

Testing the Fuel Pump…………………………………………10

Common Maintenance and Repairs: Engine .......... 11

Checking Valve Clearance……………………………………11

Changing the Piston…………………………………………….13

Checking the Cylinder for Wear and Damage…….18

Checking the Crank Rod Bearings for Wear……….20

Checking the Main Crank Bearings for Wear………21

Checking the Timing…………………………………………….22

Engine Tightening Torques ................................. 23

Bibliography ..................................................... 26

Index…………………………………………………………………..……27

Introduction

Congratulations on your purchase of the 2012 KTM

250 SX-F. The purpose of this manual is to assist

you in completing important maintenance and

repairs for your KTM motorcycle. Through following

the original KTM Owners’ Manual and this additional

reference, you will be able to more independently

work your motorcycle. This manual covers two main

sections, Fuel, and Engine. When a problem arises

with your motorcycle, refer to the troubleshooting

section and then look to the suggested instructions

for the diagnosed issue. For maintenance, you

should follow the original maintenance procedures

from the KTM Owners’ Manual. The instructions for

the common Engine and Fuel maintenance that are

not included in the Owners’ Manual can be found in

this Manual.

Note: This manual only covers in-depth Fuel and

Engine work that is not included in the Owner’s

Manual.

Troubleshooting

Troubleshooting: Fuel System

Problem

Possible

Cause

Solutions

Bike speeds

up too

slowly or

sputters

when

accelerating

Dirty Fuel Filter

Replace fuel

filter (pg. 4)

Faulty Fuel

Injector

Replace fuel

injector (pg. 7)

Bad Fuel

Empty fuel tank

and re-fill with

new unleaded

ethanol-free

gas.

Loss of fuel

pressure/Bad

fuel pump

Check fuel

hoses for loose

fittings and

possible leaks

Test fuel pump

(pg.10)

ECU Issue

Replace ECU

(pg.8)

Take existing

ECU to KTM

dealership for

re-mapping

Engine

cranks but

does not

start

Bad fuel pump

Check fuel

hoses for loose

fittings and

possible leaks

Test fuel pump

(pg.10)

Troubleshooting: Engine

Problem

Possible Cause

Solutions

Engine

Rattling

Improper Valve

Clearance

Adjust

Valves(pg.11)

Engine timing off

Adjust

Timing(pg.23)

Excess Piston

Wear

Replace piston

and rings(pg.13)

Excess Rod

Bearing Wear

Check crank rod

bearings(pg.21)

Loss of

Power

Excess Piston

Wear

Replace piston

and rings(pg.13)

Smoke

coming

out of

exhaust

Damaged

Cylinder

Check and

replace Cylinder,

piston, and rings

(pg.13)

Check oil level

Engine

will

crank

but

won’t

start

Improper Valve

Clearance

Adjust Valves

(pg.11)

Engine timing off

Adjust Timing

(pg.23)

Engine

won’t

turn over

Possible damaged

Piston, Cylinder,

or Crankshaft

Check Piston

Check Cylinder

Check Crank

Table of contents

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