|
Yamaha IT 175D

|
ake Model |
Yamaha IT 175 |
|
Year |
1977 |
|
Engine |
Air cooled two
stroke, single cylinder, |
|
Capacity |
175 |
|
Bore x Stroke |
66 x 50mm |
|
Compression Ratio |
7.4:1 |
|
Induction |
34-mm Mikuni |
|
Ignition /
Starting |
CDI /
kick |
|
Clutch |
Wet, multi-disc |
|
Max Power |
14.5 hp © 800 rpm |
|
Max Torque |
312 © 9500
rpm |
|
Transmission /
Drive |
6 Speed / chain |
|
Gear Ratio |
1st 34.081 / 2nd 22.788 /
3rd16.539 / 4th13.126 / 5th11.026 / 6th
9.262 |
|
Front Suspension |
43mm Kayaba forks |
|
Rear Suspension |
Monoshock |
|
Front Brakes |
Drum |
|
Rear Brakes |
Drum |
|
Front Tyre |
90/90 -21 |
|
Rear Tyre |
12/90 -18 |
|
Dry-Weight |
|
|
Fuel Capacity |
11 Litres |
Newcomers for 1977 in Yamaha's perennially
baffling initials game were the IT — international trial? — models, joining
YZ, DT, XS and SR variations. The ITs, first seen in the USA, were closer to
the fullblown moto-crossers, the YZ models, than to any of the others.
Large mudguards and a 2-gallon tank, all in white
polypropylene, distinguished the IT175 from the equivalent YZ model — as did the
small headlamp, of course. As on the YZ, the engine casings were of magnesium,
while the wheels and hubs were also in a lightweight metal. A double-thickness
exhaust pipe, black finished in company with the engine, was tucked away inside
the frame tubes, exiting on the right. Suspension movement nearer 6in than 12in
allowed the IT's seat to be kept low.

Review
The blue will hit you right between the eyes,
extra bright, extra sharp, and one short ride will be enough to give you that
burst of exhilaration in the pit of your stomach. Few off-road motorcycles have
ever come across as being almost exactly spot-on in production trim and yet here
one is, bigger than life with a price tag under a thousand bucks! The Yamaha
IT175D seems to be the answer to a lot of people's questions about off-road
enduro-type motorcycles. It's as much fun to play on as it is to compete on,
capable of both aspects of riding without any problems whatsoever.
If one is at all familiar with Yamaha's latest
line of YZ motocrossers, it will be apparent that there has been a lot of parts
swapping between the YZ 125 MXer and the IT175 off-roader. And though there is
much similarity, there are individual differences based on intended usage.
An overall look at the new machine will point out
the very close resemblance to the two larger ITs, the 250 and 400. Each share
color schemes and concept, just in different dosages. The IT400 was the one that
introduced the line back a little more than a year ago. Response was good enough
then to increase the line to two other displacements, but the first 1T400 and
the present one are vastly different motorcycles, the new being kind of an
updated generation.
Most of what took place in the development of the
IT 175 was done by the Japanese with very little in the way of direct American
input. While the people at Yamaha in the U.S. were running their large-bore ITs
in ISDT Qualifiers and the ISDT, they were learning much about what was needed
in the way of improvements and requirements. The Japanese listened to what they
had to say about improving the 400 and carried the same ideas and features out
on the two new ITs, without the Americans really saying, "Do this and do that."
While the engine is similar to what's been
offered in the past, it is safe to say the engine is basically new. The
mid-sized competition enduro class demands quite a bit and quite a bit is what
we're getting here. Crankshaft and barrel are similar to those found in the old
YZ 175C, but not the same. A new smaller connecting rod is used along with new
porting and a special double walled (for noise reduction) exhaust pipe with
approved spark arrestor/ silencer is a big factor in how the powerband works.
A 175 can use a good selection of gear ratios and
the IT has just that. With six speeds the little Yamaha has the right ratios for
just about any circumstance, from a crawl through the rocks to an all-out,
high-speed run across the desert. Coupled with the unusual type of powerband,
it's pretty hard to get the IT into a situation it can't handle.
The 175 is unusual because it's almost as though
it has a double powerband. There is much in the way of pulling power down in the
low rpm range, a kind of relaxation point, then there's an upper pulling range.
This should not be taken as being a pipey sort of combination. It's anything
but. It is different, however, and very pleasant. The single 34-mm Mikuni
carburetor uses a choke lever enrichening device for cold starts and performs
well under a wide variety of circumstances. Even the stock jetting remains about
right at varying altitudes, pointing out how easily the engine conforms to
different riding situations without fuss or bother.
In case a jetting change is required, it's easy
to swivel the carburetor around to pull the bottom or top off in a matter of a
few minutes. Air filtration is via a fuzz/ foam oiled element that snugs inside
a plastic still airbox assembly. To gain access to the filter, one must remove
the Phillips screw that secures the side cover/number plate and the three
Phillips screws that hold the airbox cover in place. The air intake is very
high, to help prevent water from entering during stream crossings. In case water
does manage to get in, there is a nice sized drain hole to make sure it exits
quickly. Yamaha has really done a nice job of designing the airbox to fit around
the monoshock unit which encroaches on space quite a hit in the normal airbox
area.
It is easy to be impressed by this machine's
quiet presence. It is not the least hit offensive. In addition to the double
walled exhaust pipe mentioned earlier, there is liberal use of rubber blocks in
the cylinder and head finning to hold mechanical noise down. Air intake noise is
low as well. It is pleasing to have a machine so quiet and yet so quick; nothing
has been lost in the process.
A nice touch is an aluminum skid pan that serves
to protect both the double downtubes of the frame and the engine cases and side
cases. The plate can also be removed quickly if necessary. The nice touches
don't stop here.
The IT uses its own suspension components,
virtually identical in appearance to the units found on the YZ125D, but with
different damping rates and a shorter travel monoshock unit. We feel the IT
175's suspension is just about spot-on for most of the riders who will buy this
type of machine. Only the very fast and serious jockeys will opt for the longer
travel mono unit that is used on the 125, particularly if much of their riding
is done in the desert, where higher speeds are commonplace. A woods rider would
be wasting both time and money to make the swap.
Forks feature protective rubber gaitors and
forward mount axle design and can be raised or lowered in the triple clamps to
affect changes in steering geometry. A first for Yamaha here is the use of
tapered Timken roller bearings in the steering head, definitely a quality touch.
The triple clamps are of the flat design we now see with the use of forward axle
forks.
We had our Yamaha test machine running in a great
variety of terrain with the riders having varying degrees of skill from amateur
to professional. Every one of them went away saying nice things about the
machine and gave very little criticism. The suspension absorbs small bumps hit
at slow speeds and big bumps smacked at fast speeds. That means if you're on a
leisurely trail ride in the woods, it will be comfortable. It also means that if
you're competing the following weekend in a national enduro at anything but a
leisurely pace you won't be bothered by failings in the suspension system. It is
the kind of bike that can be used by several members of a family, regardless of
their ability. That makes it a bargain, particularly when one considers the $995
price tag.
The color impregnated fenders are super wide for
good protection during muddy excursions and are unbreakable as well. The tank
and side covers follow suit. Each are of flexible plastic that is light in
weight. The tank has a good sized screw-on type cap that is easy to grip with
gloved hands and conceals a large opening in the tank so the rider can fill up
with pre-mixed fuel and see when to stop pouring.
Enduro-legal headlight and taillight are used,
not the best for riding at night but better than nothing if you happen to be
caught out after dark. Each is mounted in resilient rubber as sort of a shock
mount to preserve the life of the bulbs. An on/off switch is provided along with
a high/low beam switch. Below the lighting controls on the left handlebar is a
neat rubber-sealed kill button in an easy to use and reach position.
Back behind the comfortable seat on the rear
fender loop is a handy and useful tool bag that bolts to its own support
bracket. The machine comes with a fairly standard Yamaha tool kit: a couple of
open end wrenches, pliers, spoke wrench, box end wrench, Allen wrench, spark
plug wrench, screwdrivers and holder and a special 32-mm open-end wrench to
change the pre-load setting on the monoshock unit. The tool bag has enough
additional room to store extra plugs, tools, shop cloths and a small first aid
kit if you pack it right. Even the owner's manual contains much in the way of
good and useful information. We hope the owners of IT 175s will put the manual
to use.
Naturally, no enduro machine would be complete
without a compact, neatly installed, accurate speedometer and odometer assembly.
On the IT this unit mounts just behind the front number plate above the
headlight; a fairly well protected yet easy to reach and read location. The
speedometer face reads (unnecessarily) to 100 mph (an off-road rider really
doesn't have time to read anyway.
The glaring fault is with the odometer portion.
It seems as though after the unit is reset either forward or backward (as one
would be doing during a timed enduro at checkpoints) and the reset knob is
clicked back into normal position. the trip portion of the odometer (the
important part) doesn't begin recording mileage again until after about at least
an eighth of a mile has elapsed. This in effect makes the resettable portion of
the trip odometer worthless to an enduro rider, making us wonder how such an
item got by Yamaha. After checking around a bit, we discovered this wasn't a
fault of our particular test machine. It can be found on the majority of ITs.
We're told one solution is to install the reduction gear out of a Honda MR
series machine, but we haven't had the chance to check it out.
Back to a good note, the brakes. Yamaha has
certainly found the answer here, because the IT 175 can stop quite controllably
from all the speeds it's capable of. The units give the rider good feedback or
feel, preventing unexpected lock-up. It also takes a heavy dousing in water to
get the brake units to show any signs of fade because of wetness. Recovery time
is rapid.
The superbly strong and light Yamaha hubs lace to
D.I.D. rims with 36 spokes. Tires are motocross-type knobbies from IRC or
Bridgestone, a 4.10 x 18 in the rear and a 3.00 x 21 up front. Either wheel can
he changed in a matter of seconds with some practice, because certain design
considerations were built around ISDT criteria.
A proper centerstand will soon be available from
Yamaha Parts Distributors, and then the IT will be ready for the quickest of
wheel changes. Up front the axle has an end lever to grasp so one can more
easily turn and pull the axle out, a minor but important touch. In the rear even
more has been done.
The brake rod actuating lever pops out of the
barrel holder just by squeezing the butterfly clip and a small tab welded to the
upper brace of the monoshock swing arm holds the rod up out of the way while you
get on to the rest of the job. Loosen the axle nut, move the rear wheel and tire
forward so the chain can be slipped off the sprocket without the need of popping
the master link, then simply pull the assembly back out of the swing arm. Back
slots in the swing arm are cut out to allow this to take place. Security bolts
fit the slots so the wheel can't fall out the back of the arm if the axle bolt
isn't tight. Competitors who will make wheel changes should remove the security
bolts, others can leave them in place. Snail-type cam adjusters take up chain
slack, a positive and easy method of adjustment.
Another neat bit of trickery can be found on both
brake and shift levers. Both feature ends that pivot rearward under spring
tension in case they strike objects that would normally bend them. There's a
spring loaded chain tensioner and a roller guide on the swing arm where the
chain makes contact under compressed suspension conditions. Keeps the chain from
rubbing the arm and wearing out sooner than normal. There's even a clear plastic
cover over the headlight to keep debris from cracking the lens. Nice stuff.
Riding position seems very close to ideal. though
the handlebars may be on the low side for some riders. Footpegs too are slightly
low for running in rocky terrain, but the bike should fit most average sized
people quite well.
The best part is the fact that it's an expert's
machine that novices can ride happily all day. One must look long and hard to
find a machine that will fall into that category. Not at all hard to see why we
think the little IT 175D is one helluva motorcycle.
|