|
Yamaha IT 250

|
Make Model |
Yamaha IT 250 |
|
Year |
1980 |
|
Engine |
Air cooled, two stroke, single cylinder |
|
Capacity |
246 |
|
Bore x Stroke |
70 x 64 mm |
|
Compression Ratio |
9.8;1 |
|
Induction |
30mm Mikunis |
|
Ignition /
Starting |
- / kick |
|
Exhaust system |
Upswept expansion chamber with USFS-approved
spark arrestor and silencer |
|
Max Power |
32.27 @ 7500 rpm |
|
Max Torque |
22.60 @ 7500 rpm |
|
Transmission /
Drive |
6 Speed / chain |
|
Gear Ratio |
(1) 32/12, 2.666 (2)30/15, 2.000(3)25/16,
1.563(4)25/20, 1.250 (5)23/22, 1.045(6)21/24,0.875 |
|
Frame |
Single-downtube, full-cradle chrome-moly frame
with aluminum box-section swing arm |
|
Front Suspension |
Air-assisted, oil-damped fork with 38mm tubes
providing 270mm of travel |
|
Rear Suspension |
Aluminum-bodied monoshock with adjustable
damping and preload producing 270mm of rear-wheel travel |
|
Front Brakes |
Drum 130 x 22mm shoes |
|
Rear Brakes |
Drum 150 x 25mm shoes |
|
Front Tyre |
90/90 -21 |
|
Rear Tyre |
12/90 -18 |
|
Wet-Weight |
195 kg |
|
Fuel Capacity |
13 Litres |
Although we pride ourselves on doing thorough,
honest and informative tests, nothing short of living with a machine for several
months can reflect things like operating costs, maintenance, and most of all,
reliability. Every year we keep some test machines for extended, or long-range
testing. Some of these bikes become almost personal machines, and their care and
feeding, so to speak, is assigned to one person. Some go into our pool. They get
used by staff members, ad sales people, and photographers. The pool bikes
usually have the roughest life. Since a personal interest is absent, maintenance
usually amounts to a hurried few minutes prior to use. Most street bikes survive
this kind of treatment without complaint; few dirt bikes will survive on an
occasional ten minute maintenance period. Our IT250 and IT400 long-range test
machines proved an exception.
The 1978 1T250 was tested in the April, 1978
issue of Cycle World. We were impressed with many of its features and it became
a long-range test bike. Our Associate Publisher expressed a desire for an IT400,
so it also was added to the extended test pool.
The 250 proved the most popular, logging almost
four times the mileage in roughly the same time period. All of the users but one
preferred the 250. Several reasons were given; invariably, the first was the
weight difference. The 250 does have a much lighter, agile feeling, but actually
is only about 10 lb. lighter than the 400. The person who preferred the 400 has
a stocky build and thought the extra weight a reasonable trade for the beautiful
low-end pulling power. Low-end pulling is about the only thing the 400 did
better than the 250 though. The 250 was fastest in a straight line drag race,
had the highest top speed (it humbled many MX test bikes throughout the year,
some of them open-class bikes), and was the easiest to ride in the woods.
Both were incredibly reliable and neither bike
failed to finish a ride. During the 568 mi. put on the IT400, the only parts
replaced were clutch and brake levers damaged in a crash and one footpeg bolt
which fell out. Thread sealant applied to the replacement kept the bolt from
falling out a second time.
With 2236 mi. on the IT250, the report is more
revealing. Clutch and brake levers were replaced with MTD Power Levers shortly
after the clutch lever was broken in our shop when the bike fell over. The seat
was ripped during the same fall and Yamaha supplied a new seat when we asked for
a new seat cover.
At 400 mi. a Uni filter replaced the stock air
cleaner.
At 1500 mi. both tires were replaced. At 2200 mi.
the chain and both sprockets were replaced.
Two spark plugs went in during the test, not
because of fouling but as preventative maintenance.
Three sets of American Pro grips were used during
the test.
That's it. The head never came off, nor did the
side case on either bike. Fork seals and fork oil was never changed, no spokes
or cables were replaced and even the throttle cable went the entire distance.
Sure isn't much for the hard use the bikes received.
We used Bel-Ray MC-1 mixed 60:1 in both machines
and never fouled a spark plug or had any engine gumming. Chain lobes were mostly
Bel-Ray and PJ-1.
The 250 pre-ran one Baja 500, one Mexican 1000
and survived three other trail rides into Baja. It also participated in numerous
trail and photo rides into the San Bernardino Mountains and Mojave Desert. The
ITs were reliable, dependable and trustworthy. They never failed to finish an
outing, and we began to trust them to take us anywhere, at anytime, with little
or no preparation.
Complaints? Only one. Lack of steering precision.
We tried bolt-on cures and fooled around with stanchion tube height hut nothing
could compensate for a steering head angle set for straight line stability,
instead of turning.
Art Director Paul Zeek probably explained the
IT's steering best: "There is only one way to miss a rock while at speed on an
IT—aim for it.
The lack of steering precision was noticed more
by motocrossers and experienced off-roaders than first timers and novices. This
complaint has been cured on the '79 ITs by pulling the rake angle back 2°. A
good shop could modify the '77 and '78s by cutting the backbone and pulling the
rake angle back the same amount.
Anyone who likes to ride dirt bikes but hates to
work on them should take a good hard look at Yamaha's ITs. They are fast, tough,
ready-to-ride hikes that will give an owner thousands of carefree miles on the
trail and be ready to go any place, anytime, without days of preparation and
preventative maintenance. |