The engine is maybe the most exiting part of an ATV. Due
to the age of my Oddy, it's equipped with a 2 stroke. Today's ATVs are
powered by 4 strokes.
(August 2003)
Compared with 4 stroke engines, 2 strokes are more powerful at the same
displacement and burn more fuel in comparison to their 4 stroke
brothers.
The emissions are more critical, too. This why some recreation parks either banned two
stroke engines or their number is limited. Due to state-of-the-art engine oils (mostly
synthetic), the emissions have been vastly reduced over the years. More here.
My Honda Odyssey is powered by a Curtiss Wright KEC 400ccm engine. More
here.
If you are interested in general 2 stroke information, click on '2 Stroke
Engines' on the left side. Ton of stuff there.
Click on the 'play' button below to listen to my Oddy's engine
running at 1,500..3,000 rpm. Max rpm is 6,500.
KEC 400 Engine Check
On 8/9/03 I opened up the head of the engine in order to determine the amount
of damage to the pistons and the cylinder walls.
Cylinder 1 (right side)
(piston in lower position, left hole is exhaust port, upper
hole gas mixture port)
(piston in upper position, piston head carbon build-up.
Arrow points to exhaust outlet)
(cylinder head lower side, spark plug in the middle. Head bolt
wholes (5))
Cylinder 2 (left side)
(left and ridght holes are mixture ports, arrow points to exhaust port,
burn marks on right side)
(piston head with carbon build-up, oil sludge at the right
side, next to the other head heat sink (in reality lower side))
(cylinder head lower side, spark plug in the middle. Head bolt
wholes (5))
Assessment
Both piston heads show signs of carbon build-up which most likely was
caused by an improperly adjusted carburetor.
The cylinder head also shows carbon build-up, but is in good condition.
Cleaned it.
The cylinder walls do show marginal sign of scars. Since the engine's
mounted in an 45 degree angle, it seems obvious that the scars are on the lower
side only. My
assumption this is because of the piston's weight and/or exhaust
particulars.
The cylinder seals will be replaced in the future since they seem to be
worn and were leaking. Bought them already.
Found no evidence of oil slugging inside the engine (no wonder, it's a two
stroke). Due to leaks in the cylinder, there was oil sludge outside of the engine.
Cylinder 2 (left side) has burn marks at the head seal left side. Not sure
what caused this. Maybe defective seal or improperly torqued head bolts.
Bottom line: No need to replace engine. It is not in perfect
condition, but O.K. for now. If necessary, engine can be replaced since I
bought 2 spare, pre-owned engines of the same type.
DL3SJB's World
Last updated
05/31/04.
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