Honda NU50 User Manual

TROUBLESHOOTING
~HONDA
~NU50.NU50M
ENGINE LACKS POWER
Probable Cause
,. Rev vo gradually ENGINE SPEED DOES NOT
INCREASE ----------
ENGINE SPEED INCREASES
III Cloggedaircfeaner
(2) Ctogged fuel line
131 Clogged fuel tank cap breather hole
141 Clogged muffler
2. Check ignll on ,mmg
INCORRECT TIMING;-------- III Faulty C.D.1. unit
t21 Faulty alternator
CORRECT TIMING
I
3. Test cylinder compre5Sion
NORMAL COMPRESSION
1
LOSS OF COMPRESSION' -----
(1) Worn cylinder and piston nngs
(2) Blown cylinder head gasket
(31 Flaws in head or cylinder
(4) Faulty feed valve
4. Check carburetOl for clogging CARBURETOR CLOGGED -----
0) Carburetor jets dogged
CARBURETOR NOT
CLOGGED
j
5. Remove spark plug
PLUG FOULED OR OISCOLORED- (1) Fouled plug
(2) Incorrect heat range plug
POOR PERFORMANCE AT IOLE AND LOW SPEED
(1) Excessive carbon in combustion
chamber
(2) Incorrect or poor Quality fuel
(3) Slipping c1UlCh
(4) Slipping drive belt
iSI Mlxt\Jre toO lean
ENGINE KNOCKS -------
ENGINE OVERHEATS ------
(J) Worn piston or cylinder
(21 Mixture lOa lean
(3) Incorrect or poor qualitv fuel
(41 Excessive carbon in combustion
chamber
(5) Ignition timing tOO early
Probable
Cau~e
INCORRECT TIMING ------- •• (1) Incorrect timing Haulty C.D.1. unit
or alternator)
ENGINE
DOES NOT
KNOCK
7. Rapidly accelerate or run
<It high SPl!ltUS
1. Check ignition timif'g
ENGINE DOES NOT
OVERHEAT
J
PlUG NOT FOULED
OR DISCOLORED
I
6. Check If engine overheats
•
CORAEC{ TIMING
2. Check c3rburelOr ait screw
adjustment
INCORRECTLY ADJUSTED ----- (1) Mixture 100 rich (turn out screw)
j21 Mixture 100 lean (turn in screwl
COR
RECTL Y ADJUSTED
I
3. Check lor all leal..s
NO AlA LEAKS
AI R LEAKS -----------~ (11 Faulty carburetor gasket
121 Carburetor not securelv tighten~d
t31 Faultv Intake Pipe gasket
j41 Faultv carburetor O·ring
4. Remove spiuk plug and test
spark
GOOD SPARK
""lEAK OR INTERMITTENT SPARK
(1) Faultv or fouled plug
(2J FauilY C.D.1. unit
(3) Faulty alter nato,
141 Broken or shorted high tenSion 'mre
IS) Open or shorted Ignition coil
(6) FauilY ignition switch
15-2
164 Date of Issue: Nov., 19B1
© HONDA MOTOR CO., LTD.

Honda NU50 Specifications

General

Model	NU50
Category	Scooter
Ignition	CDI
Transmission	Automatic
Final Drive	Belt
Front Brake	Drum
Rear Brake	Drum
Front Tire	2.50-10
Rear Tire	2.50-10
Starting System	Kick start
Rear Suspension	Unit swing
Fuel Capacity	4.5 L