Yamaha Xj550j Maxim

YAMAHA XJ550J MAXIM

CYCLE WORLD TEST

Yamaha's Maxim 550 followed the Seca 550 into the marketplace and shares many parts with the sporty Seca. But the cruiser-styled Maxim is farther from the Seca than styling alone would suggest, in terms of feel and performance. This is not simply a motorcycle with a different gas tank and seat and sidecovers to match a changed nameplate. Instead, this is a motorcycle nicely engineered for its intended market and purpose.

There is, of course, the styling. A swoopy tank and abbreviated sidepanels combine with a stepped seat, which terminates in an alloy grab bar. Perched out on the end of the short rear fender is the chrome taillight/license plate holder.

The 4-into-2 exhaust system includes an expansion box between the head pipe, ahead of the mufflers, secured with its own rubber mount. The mufflers sweep upwards and the ends are cut off at an angle.

The leading-axle front end has a chrome fender, headlight and instruments. The upper triple clamp is a beautiful, polished cast alloy piece incorporating set-backs which bring Seca-style handlebars back toward the seat, accomplishing the cruiser seating position without using outlandish pullback bars.

The effect is a sport-edged custom, a bike incorporating the hot-selling semichopper styling without going overboard.

Like the Seca, the Maxim has a 528cc dohc inline Four with two valves per cylinder and shim valve adjustment. Bore is 57mm and stroke is 51.8mm. Compression ratio is 9.5:1 and the cylinder head incorporates the Yamaha Induction Control System (YICS), in which small, interconnected sub-ports shoot a highvelocity stream of gas-air mixture into the cylinder, swirling the charge for better efficiency.

Power is taken from the crankshaft to a jackshaft by a hydraulically-tensioned Hy-Vo link plate chain. One side of the jackshaft carries the alternator, positioned behind the cylinders to narrow the engine. The other end of the jackshaft drives the clutch hub through gears. The transmission has two shafts carrying six gearsets, and final drive is by roller chain.

Cam drive is roller chain off the center of the crankshaft. Maxim camshafts are different than the cams used in the Seca. The Seca’s intake valves lift 7.8mm, its exhausts 7.1mm. The Maxim has 6.8mm lift for intakes and exhausts. The Maxim’s intake valves open 26° BTDC and close 46° ABDC for 252° of duration, while the exhaust valves open 46° BBDC and close 26° ATDC, again yielding 252 ° of duration. The Seca has intake cam timing of 29-59° (duration 268°) and exhaust timing of 57-27° (duration 264°), which gives more peak power at higher rpm. Because the powerbands are different, the Seca is redlined at 10,000 rpm and the Maxim at 9500.

The Seca engine is peaky, demanding lots of rpm when moving through traffic or getting away from stoplights. The Maxim, however, is perfectly happy to get moving at relatively low rpm and to progress through city traffic while being shifted at 4000 or 5000 rpm (it does make its best power above 7000, however). Helping the Maxim leave with minimal fuss is effectively lower gearing (internal ratios and final drive sprockets are identical) due to a smaller diameter rear tire than found on the Seca.

The Maxim, then, makes its power lower on the powerband, and acceleration falls off sharply if the bike is revved past redline. Below 9500, the Maxim pulls well, and will reach maximum rpm in top gear, while the Seca cannot pull its rev limit no matter how much room it has to try.

At the dragstrip the Maxim is understandably slower than the Seca, turning the quarter-mile in 13.3 sec. with a terminal speed of 97.82 mph, compared to the Seca’s 12.99 sec. and 98.57 mph. But because the Maxim’s gearing and power output are better matched than the Seca’s, the Maxim is actually faster in the half mile top speed test, reaching 111 mph (calculated top speed at 9500 is 112 mph) compared to the Seca’s 110 mph (theoretical top speed is 127.73 mph).

The changes in power delivery and gearing also improved gas mileage, the Maxim returning 60.5 mpg on the Cycle World mileage test loop, a combination of city traffic, country roads and expressway. The Seca, demanding more rpm at all times, didn’t do quite as well with its still-creditable 56.9 mpg.

There is—isn’t there always?—a tradeoff. In the Maxim’s case it is on the open highway. The Maxim spins faster at 60 mph (5076 rpm to be exact) than the Seca (4932 rpm) and in spite of the same rubber engine mounts, some buzzing vibration reaches the rider and blurs the mirrors. And because the iMaxim’s sleeker tank is also smaller (3.4 gal. vs. 4.2 gal.), it can’t travel as far as a Seca on a tankful, better mileage or no better mileage. For the record, the range of the Maxim in typical use is about 130-150 mi. before reserve is required. The Seca can usually go 160-185 mi. before going on reserve. (Bear in mind that these figures apply to mostly-legal speeds, not banzai runs across stretches of deserted highway).

Not Just a Seca in Cruisers Clothes, but Rather a Motorcycle Engineered for its Intended Purpose

There are other differences. The Maxim gets a set of leading-axle forks to accentuate the kicked-out-front-wheel look of cruisers, and that change combines with 1 ° more steering head angle (to slow down the steering) to produce an *xtra 0.4 in. (10mm) of wheelbase. According to Yamaha specifications, that should bring the wheelbase to 55.7 in. According to our tape measure, with the rear wheel about in the middle of its chain tension adjustment range, it’s 56.8 in. The steering head angle change also increases trail 0.2 in. (5mm).

The Maxim weighs more than the Seca with half a tank of gas, in spite of the smaller fuel tank. At 432 lb. the Maxim outweighs the Seca (424 lb.) by 8 lb. The weight comes from the heavier leadingaxle forks and the larger (wider) cast rear wheel. The Maxim rear wheel is 16 in. in diameter, compared with the Seca’s much narrower 18-in. wheel.

Beyond the technical features, the Maxim works well in the real world. It starts from cold instantly with full choke (operated by a lever on the left handlebar control pod) and can be ridden away without waiting. And it starts without requiring that the rider pull in the clutch lever, because the electric starter is not interlocked with the clutch. Instead, Yamaha uses a sidestand interlock. That is, the bike starts and runs in neutral with the sidestand down, but if the rider engages gear without first retracting the sidestand, the ignition is cut and the engine dies.

Once running, the Maxim has a deep, throaty exhaust note that sounds exciting. Carburetion is perfect, with no flat spots from idle to redline. The 28mm (nominal) Mikuni C V carbs give constant velocity carburetors a good name, and make one wonder why the CV carburetors on Suzukis used to be so awful.

The Maxim feels small for a 550, and is. The low seat (30.5 in. from the ground) and the relationship of the seat to the footpegs and handlebars makes the machine ideal for shorter riders. It is easy to believe that the Maxim (and the Seca, for that matter) is based on a home-market 400 Four, because it feels more like a 400 than a 550.

The Maxim is not as smooth on the highway as some machines, including the GS650 Suzuki and the Seca 550. But jump onto a Maxim after riding a Yamaha XV920 or other large Twin (of any configuration) and you’ll wonder what this talk of buzziness or vibration is all about. It isn’t a problem.

The suspension is compliant and does a good job of absorbing bumps. Get the Maxim out on the Long Island expressway and you’ll feel those concrete expansion joints more than you would on some bikes. But there isn’t another 550 than does a better job on such small, repetitive bumps.

The performance of the stylish seat, however, is not so clearcut. It seems to depend on the physical size of the rider involved, but even smaller riders can find the comfort limits of the seat, given enough time in the saddle. One taller rider found the seat uncomfortable after 30 min. Another slightly shorter pilot could ride 45 min. before shifting feet to the passenger pegs and squirming. The trouble with step seats, no matter how visually appealing, is the lack of flexibility—the rider cannot easily slide forward or rearward on the seat to alter his position. Instead, the step seat locks the rider into one position, making no allowances for arm and leg lengths or even rider preferences.

To match its small apparent size, the Maxim is responsive and nimble. It steers easy and handles well, although anybody intent on berserking it down twisty canyon roads may find the suspension and steering a bit vague in high-speed sweepers—the rear end pogos slighty, setting up a slight front-end oscillation. It’s only noticeable at very high speeds, and never in a straight line.

The transmission and clutch deserve special mention simply because they work so well. The clutch pull is next to nothing, and the transmission shifts slickly and easily. With the engine’s new torque, the six-speed seems to have almost too many gears, especially in the middle of the gearbox. It’s then that the rider who wants to shift at 5000 rpm finds himself grabbing a gear (it seems) every 100 ft. Yamaha engineers probably could have spaced the middle gears farther apart—the Maxim doesn’t need a closeratio the way the Seca does—and turned 6th into a true overdrive that let the engine turn slower on the highway.

The change would not have made much difference at the drags, since the Maxim (like most bikes) doesn’t get into high gear in the length of one quarter mile. And the powerband achieved by changing the cam timing is wide enough to handle taller gearing in top.

The instruments are exceptionally clean and easy to read, with a minimum of idiot lights and no flashing warnings and computers. Like the Seca, the Maxim has an oil level warning system instead of an oil pressure warning. When the oil level warning light comes on the rider who hasn’t checked the oil lately still has plenty of time to ride to a gas station or motorcycle shop and buy oil. Anybody who waits until an oil pressure light reminds him to add oil is likely to be in for some very expensive repairs.

Night lighting of the instruments is exceptional, although the headlight is not as powerful as the one found on the Seca. The turn signals are mounted on flexible rubber stalks, a nice touch which minimizes damage if the bike falls over in the garage or in a parking lot. Instead of snapping off or bending like conventional, rigid turn signal stalks, the Maxim’s rubber stalks just move mostly out of the way. It’s still possible to break the turn signal lens with a tip-over, but it’s just as likely that the signals will escape with no damage worse than a few scratches.

The horn is not innovative and is less than outstanding. It is not loud enough. That fact is curious considering the excellent dual horns on the Seca.

The whole of the Maxim—taken within the context of it intended purpose and market—overrides its shortcomings. For people who prefer stylish cruisers, the Maxim is the best of the mid-s-ize examples of the type. H

YAMAHA XJ550J MAXIM

SPECIFICATIONS

$2599

PERFORMANCE