Troubleshooting; Compression Too High; Excessive Smoke; Excessive Noise - Honda TRX400EX FOURTRAX 1999 Service Manual

CYLINDER HEADNALVE
TORQUE VALUES
Upper engine hanger nut
Cylinder head nut
Cam sprocket bolt
Cam chain tensioner plug
Rocker arm shaft
Sub-rocker arm shaft
Cylinder head cover bolt
Spark plug
TOOLS
Valve spring compressor
Valve guide driver, 5.5 mm
Valve guide reamer, 5.5 mm
(IN
Valve seat cutter, 35 mm
Valve seat cutter, 29 mm (EX 45")
Flat cutter, 35 mm (IN 32")
Flat cutter, 30 mm (EX 32")
Interior cutter, 30 mm (INIEX 60")
Compression gauge attachment
Cutter holder, 5.5 mm

TROUBLESHOOTING

Engine top-end problems usually affect engine performance. These can be diagnosed by a compression test, or by tracing
top-end noise with a sounding rod or stethoscope.
If the performance is poor at low speeds, check for a white smoke in the crankcase breather tube. If the tube is smoky.
check for sized piston ring (section
Compression too low, hard starting
at low speed
Valves
- Incorrect valve adjustment
- Burned or bent valves
-
Incorrect valve timing
-Broken valve spring
-Uneven valve seating
-Valve stuck open
Cylinder head
-
Leaking or damaged cylinder head gasket
-Warped or cracked cylinder head
-
Loose spark plug
Cylinderlpiston (section
Compression too high
Excessive carbon build-up on piston head or combus-
tion chamber
Worn or damaged decornpressor system

Excessive smoke

Worn valve stem or valve guide
Damaged stem seal
Cylinderlpiston problem (section
7-2
54 N.m (5.5 kgfm, 40 IbfW
44 N m (4.5 kgfm, 33 Ibf.ft) Apply oil to the threads and seating surface
20 N m (2.0 kgf.m, 14 IbfW Apply locking agent to the threads
4 N m (0.4 kgfm, 2.9 IbfW
27 N.m (2.8 kgfm, 20 IbfW Apply locking agent to the threads
27 N m (2.8 kgfm, 20 IbfW Apply locking agent to the threads
26 N m (2.7 kgfm, 20 IbfW
18 N.m (1.8 kgfm, 13 IbfW
07757 -0010000
07742- 0010100
-
07984 2000001 or 07984
45")
07780-0010300
07780-0012300
07780-0012200
-
001 4000
07780
-
07908
07781-0010101
or poor performance
-
or equivalent commercially available in

Excessive noise

Incorrect valve clearance
Sticking valve or broken valve spring
Excessive worn valve seat
Worn or damaged camshaft
Worn or damaged rocker arm and/or shaft
Worn rocker arm follower or valve stem end
Worn cam chain
Worn or damaged cam chain tensioner
Worn cam sprocket teeth
Cylinderlpiston problem (section
Rough idle
Low cylinder compression