So Much So Right, So Little So Wrong

SO MUCH SO RIGHT, SO LITTLE SO WRONG

CYCLE WORLD TEST

YAMAHA IT250

Enduro bikes have been a staple of the Yamaha line for several years. Mostly they've been designed for the Sunday fun market rather than the serious or semi-pro enduro competitor (the 1982 IT-465 being the exception that proves the rule). The IT250 has been a good seller all these years despite its never winning national races or magazine awards.

This success has been for good cause. The people who buy the IT250 know it isn’t perfect. But they don’t mind fixing this and modifying that because they also know the ITs keep running year after year, seldom breaking or needing new parts.

It was with some secret delight, therefore, that we heard the factory reps at the 1983 model show claiming that the ITs were all new, no compromise, raceready enduro weapons, bristling with full-zoot YZ features. Sure, we yawned, they say that every year.

Hype aside, the ITs are not YZs with lights, nor should they be. Instead, which is the way it should be, the ITs gain from the YZ’s example.

Perhaps the two best features on the 1983 IT250 are the frame and suspension travel: the frame is almost the same as those used on the YZs. It’s made of strong, large diameter steel tubing, heavily gusseted and triangulated. The 28° steering head uses caged bearings, the triple trees have double-bolt clamps, the footpegs are mounted higher on the frame, are attached to heavy plates and have wide, serrated tops. Most important, the rear shock is placed in the same position as the YZ, low in the frame, and attached to new aluminum levers. The swing arm is boxed aluminum much like those used on the YZs but equipped with cam adjusters and a quick-change brake rod.

Adjusting the shock’s spring preload is a simple job. The adjuster nut is on the bottom of the shock where it’s easily reached and turned using a supplied Yamaha tool. Just below that is a knurled knob with 25 rebound damping positions. The aluminum-bodied shock doesn't have provisions for adjusting the compression damping. The looselywound, one piece, straight-rate spring works just fine, thanks to the progression built into the rear suspension’s aluminum linkage.

Forks are KYB, have 43mm stanchion tubes, 11.8 in. of travel and good fork gaiters protecting the seals. They are adjustable by changing oil weight and volume. Optional springs, softer or stiffer, are available from dealers.

Wheels and hubs are strong and light; the rims are aluminum. Yamaha’s new generation hubs look like past hubs but are actually quite a bit thinner and lighter due to new production techniques. Brakes are single leading shoe rear, dual leading shoe front. Tires are IRC and actually work quite well as long as they are run with less pressure than normal. We found 8 psi front and 10 psi rear worked best.

The IT250 engine is a compact design with no excess casting material; the cases are shrunk-fit around the cylinder studs, clutch throw arm and primary drive gear. A strong, six-speed transmission is standard. The six-spring clutch has seven friction plates and six steel plates. The clutch basket is aluminum. Don’t worry about clutch problems on this bike, the clutch is the same as the IT490.

A dual-ring piston fits into a borable steel-lined aluminum cylinder. A 36mm Mikuni carb feeds gas through a sixpetal reed, a boost bottle (called a Y.E.I.S. air chamber by Yamaha) helps low-speed torque. An outside flywheel CDI ignition produces a strong spark and is maintenance free. The exhaust pipe is routed high in front to reduce contact damage. A big silencer/spark arrester makes the IT legal in the woods.

The 250 IT has an excellent airbox with a dual piece top that winds the air through a maze, while water is routed out a drain at the front of the box. The filter is foam and if you do somehow manage to drown the engine, the side of the airbox and right-side number plate are easily removed.

Riding the IT250 is both pleasurable and disappointing: the bike handles well, the suspension works, it steers with precision, starts easily and is comfortable. The bars and controls are placed right and most work smoothly, and the bike is very easy to move about on.

So what’s disappointing? Mainly it’s a problem with power delivery. The engine is weak on the bottom and struggles up from idle until Bang! there’s a great surge until just about the time the rider figure’s the muscle is really coming on, then it falls flat again. This isn’t a flaw in any one system, as in the jetting or the pipe or something like that. Instead, it seems as if the designers deliberately did everything, from boost bottle through porting to exhaust pipe, with the aim of giving the enduro rider a strong midrange, which is just what we always asked for. They’ve done that, at the cost of taking away from engine performance the rest of the time. That works for motocross and road racing because the rider can tune and plan for a short, closed course. It doesn't work when everything around the next turn will come as a surprise.

Going fast requires constant shifting to keep the engine in its narrow midrange. Complicating matters, the shifting is on the stiff side. It’s not as hard to shift as some we've ridden, but it’s far from being pleasant. It does shift positively; no one missed any shifts. Gear ratios are good. If the bike is in the sweet zone of the power band, the IT will move along without any noticeable lag between shifts.

The forks are too soft as delivered. We raised the oil level a half inch and got rid of the wallow. The rear suspension is time-consuming to adjust. Since the compression damping isn’t adjustable, spring preload becomes critical. There is a noticeable difference in a half turn of the spring preload ring. Take the time to adjust it properly and it’ll work fine.

Yamaha’s ITs have been fairl-y well equipped with enduro accessories for a couple of years and ’83 is no exception; plastic hand guards protect the dogleg levers and the rider’s knuckles, the easyto-read odometer has a large-diameter reset knob, the headlight/number plate has a neat, quick release, the headlight has a bright, white light and good on/ofT switch, the taillight is large and blends "nicely into the rear fender, although it is too far back. A flimsy tool bag is standard and it’s complete with several handy wrenches: there are normal poorquality end wrenches and screwdrivers but the spring preload hook wrench and lock-nut wrench make the kit worth-

while. Extra frame tubes are bolted to each side of the lower front of the frame. They wrap around the front of the engine’s cases and combined with welded on tubes below the engine, protect the engine without collecting mud.

Yamaha has done a nice job of making a 3.6 gal. gas tank look good. The tank is fairly low on the frame and blends into the side panels. The thick seat extends up the back of the tank. The radical climb means the rider can't slide up on that part of the seat but it does pad him nicely if he’s suddenly slammed forward.

Brakes are excellent. The double-leading shoe front will haul the bike down to a crawl from eye-watering speeds with

little elTort from the rider. The rear is strong but doesn't stall the engine if the rider panics and jabs it, and both are fairly waterproof.

Like all Yamaha Monos, the IT is narrow in the middle and easy to move around on. The thick seat is comfortable for all-day rides and the cover holds up well. The side number plates are nicely styled but aren’t as sturdy as they should be; The left side split the second ride.

That’s the only failure we had with the IT250. We rode the IT in the mountains, desert and Baja. It never failed to start or run all day. All together it has gone over 1000 mi. It’s not perfect but it does endure.

YAMAHA

IT250

$2049