Troubleshooting And Repair - Yamaha LB50IIAC Service Manual

Main nozzle
Pilot jet
NOTE:~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1. Banjo bolt holding main jet can be removed without any disassembly.
2. Carefully set body aside and inspect each independent float within the float bowl cavity. Note
their installation position. The float arm pin must be at the bottom of the float bowl and
pointed in. toward the center.
3. Wash the carburetor in petroleum base solvent. Wash all associated parts.
4. It is rarely necessary to use special carburetor cleaning solutions, if deposits warrant this
procedure. remove the Starter Jet Assembly to avoid damaging the neoprene valve seat.
5. Using high pressure air, blow out all passages and jet's.
6. Never direct high pressure air into carburetor with float bowl installed. Damage to floats may
occur.
7. Inspect the needle and seat for signs of excessive wear or attached foreign particles. Replace
as required. Always replace inlet needle and inlet valve seat as an assembly.
8. Inspect pilot air screw for signs of excessive wear or attached foreign particles. Replace as
required.
Troubleshooting and repair
Carburetor Specifications
Model
Part Name
Abbrev.
LB50 ll AC
LBBOJIAC
Manufacturer - Model -
M ikuni VM 14SC
Mikuni VM 16/1
I.D. Number
-
2T5-00
1 F5-01
Venturi Size -
14mm 16mm
Main Jet M.J.
#95
<--
Needle Jet
N.J. E-4
E-8
Jet Needle/Clip Position
J.N. 3G9/3
+-
Cut Away C.A. 2.5
+-
Pilot Jet
P.J. #17.5
#15
Air Jet A.J. Drill 2.5q,
+-
Starter Jet
S.J. #20
#25
Air Screw (Turns Out) A.S. 1
1-3/4
Idle Speed - 1.350± 100rpm
+-
Float Level
F.L.
22.0
+
2.5 mm
+-
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