Yamaha MX250 - Page 5

HOW TO USE THIS MANUAL
This manual is intended as a handy, easy-to-read reference book for the mechanic.
Comprehensive explanations of all installation, removal, disassembly, assembly, repair and check
procedures are laid out with the individual steps in sequential order.
• The manual is divided into chapters and each chapter is divided into sections. The current section
title is shown at the top of each page “1”.
• Sub-section titles appear in smaller print than the section title “2”.
• To help identify parts and clarify procedure steps, there are exploded diagrams at the start of each
removal and disassembly section “3”.
• Numbers are given in the order of the jobs in the exploded diagram. A number indicates a disas-
sembly step “4”.
• Symbols indicate parts to be lubricated or replaced “5”.
Refer to SYMBOLS.
• A job instruction chart accompanies the exploded diagram, providing the order of jobs, names of
parts, notes in jobs, etc. “6”. This step explains removal procedure only. For installation, reverse
the steps.
• Jobs requiring more information (such as special tools and technical data) are described sequen-
tially “7”.
4-3
1
2
3
5
6
7
8
9
10
DISASSEMBLING THE CARBURETOR
CHECKING THE CARBURETOR
1.
Measure:
• Float height “a”
Out of specification → Replace.
TIP
• Lift up the float so that the tip of the float valve lightly
contacts the float arm, and then measure the float height
“a”.
• Do not adjust the float height.
2.
Check:
•Jets
• Carburetor body
Clogged → Apply compressed air to clean the jet.
3.
Check:
• Valve seat
Wear/damage → Replace.
Dirt → Clean.
a
Float height:
13.8 mm (0.54 in)
a
b
a. Wear at groove
b. Dirt
4-2
DISASSEMBLING THE CARBURETOR
DISASSEMBLING THE CARBURETOR
Order Job/Parts to remove Q’ty Remarks
Disassembling the carburetor Disassemble the parts in the order listed.
1/1gnirpS/wercs niarD1
1tlob rebmahc taolF2
1teksaG3
1rebmahc taolF4
1teksaG5
1nip taolF6
1taolF7
1ylbmessa eldeeN8
1elzzon niaM9
1evlav elttorhT01
11 Throttle stop screw/Spring 1/1
1tej toliP21
1tfahs elttorhT31
1evlav ekohC41
1revel ekohC51
1
2
3
4
5
7
6
8
9
12
11
10
13
14
15
0.7 N · m (0.07 kgf · m, 0.52 lb · ft)
0.7 N · m (0.07 kgf · m, 0.52 lb · ft) 1.6 N · m (0.16 kgf · m, 1.2 lb · ft)
1.3 N · m (0.13 kgf · m, 0.95 lb · ft)
1.1 N · m (0.11 kgf · m, 0.81 lb · ft)
7 N · m (0.7 kgf · m, 5.2 lb · ft)
1
3
7
2
5
4
6