Maico 490 Alpha 1

 

 

 

Make Model

Maico 490 Alpha 1

Year

1982

Engine

Single cylinder, two stroke

Capacity

488 cc / 29.8 cub in.
Bore x Stroke 86.5 x 83 mm
Cooling System Air cooled
Compression Ratio 12:1
Lubrication Oil in fuel, premix
Fuel/oil ratio 20:1
Oil Capacity 0.60 L / 0.63 US quarts
Exhaust Upswept with repackable silencer

Fuel System

Bing, 40 mm carburetor

Ignition 

Motoplat pointless electronic

Spark Plug

Champion NZ, N84G or NGK B9ES
Starting Kick start

Max Power

32.1 kW / 43.7 hp @ 6500 rpm

Max Torque

36.5 Nm / 3.7 kgf-m / 26.9 ft/lb @ 6000 rpm
Clutch Wet, multi-disc

Transmission 

5-Speed, constant mesh
Final Drive Chain
Gear Ratio 1st 2.71 / 2nd 1.97 / 3rd 1.50 / 4th 1.20 / 5th 1.00:1
Frame Dual down tube, full cradle, chrome-molydenum

Front Suspension

Leading axle, air/spring fork
Front Wheel Travel 305 mm / 12 in.

Rear Suspension

Corte & Cosso reservoir single gas shock adjustable for damping and preload
Rear Wheel Travel 320 mm / 12.6 in.

Front Brakes

Single leading shoe, drum 136 mm

Rear Brakes

Single leading shoe, drum 160 mm
Wheels Akront, aluminium alloy, gold anodized, laced wire spokes
Front Rim 1.60 x 21 in
Rear Rim 2.15 x 18 in.

Front Tyre

3.00 x 21 in., Metzeler, moto cross

Rear Tyre

4.50 x 18 in., Metzeler, moto cross
Rake 28.5°
Trail 126 mm / 4.96 in
Wheelbase 1510 mm / 59.5 in.
Ground Clearance 372 mm / 14.6 in.
Seat Height 960 mm / 37.7 in.
Dry Weight 108 kg / 237 lbs
Wet Weight 113 kg / 249 lbs

Fuel Capacity 

9.5 L / 2.5 US gal
Review Cycle, April 1982, Pulpmx.com

The big Maico 490 jumps to the front of suspension technology with its single-shock Alpha Control rear suspension system. So after seeing a single-shock rear suspension system on last year's factory race bikes, we were not surprised to find the 1982 production motocrossers featuring single-shock setups. The new Maico rear, named the Alpha Control

The suspension, is built around a single nitrogen-charged, remote-reservoir Corte & Cosso shock. The top of the shock mounts to the frame; the bottom end connects to an aluminum rocker that fastens to the frame and the steel box-section swing arm. The Alpha Control is a rising-rate system: as the rear end compresses, the rear wheel travels progressively less in relation to shock travel. So for a given amount of wheel movement, the shock moves farther during the final portion of the wheel's travel than in the beginning. This, in effect, progressively increases the shock damping and springing rates, which have the rear wheel respond quickly at first and then require a severe load to compress the shock completely.

Since this is Maico's first try at a single-shock system, we expected to find some bugs. Not so. We were pleasantly surprised to discover that the Alpha Control works very well. The rear end is much better than last year's twin-shock Corte & Cosso setup, largely because of the progressive action of the rising-rate linkage. The shock bottoms only lightly, thanks to the linkage and the large foam-rubber stop bumper on the shock shaft. The Alpha Control rear suspension provides 12.6 inches of travel, an increase of 0.8 inch over the 1981 490. Though there's a wide range of adjustability, the shock action is a bit harsher than other single-shock rear suspension systems. The shock's easily accessible adjusting knob makes setting the rebound damping to one of about 60 positions easy. The shock worked well set 30 clicks in from the fully backed-off (counterclockwise) position. We liked the shock's springing when set up with 200 psi of nitrogen in the shock reservoir and enough preload to set the shock spring length at about 9.5 inches. Naturally, these settings varied with rider weight and different track conditions. There's just one snag in the shock spring preload adjusting collars; the aluminum threaded rings deform rather easily if you change preload settings with a hammer and punch. Change them often as you travel from track to track and your shock will soon be well scarred.


Maico made a few minor modifications to the 488cc power plant in an effort to boost mid-range and low-end power. The new air filter has 40 percent more area than last year's version, but the seat base restricts airflow. Cutting a hole in the right side of the airbox improves airflow and engine performance.

The 490's powerplant remains basically unchanged from last year's version. The 86.5 x 83.0mm bore and stroke displace an actual 488cc, and the four-transfer-port cylinder follows basic two-stroke design; the Maico is devoid of any fancy reed setups or trick boost ports.

The aluminum intake manifold now angles toward the bike's left side in order to clear the centrally located rear shock. The big 40mm Bing carburetor is the same as last year's, but the air filter reportedly has 40 percent more filtering area than the '81 bike's.

For 1982, Maico made a few minor changes to alter the 490's power characteristics. A new exhaust pipe and re-angled transfer ports supposedly increase the Maico's low-end and mid-range power, but we questioned this claim after our first ride. Traditionally, big-bore Maicos have a lot of flywheel effect and are known for their smooth, usable powerbands. Our Alpha 1 felt as if it was running rich; it pulled like a strong 250 rather than a high-horsepower open-classer. In a drag race against a Husqvarna 430, the 490 held even until third gear; then the Husky squirted away. That was surprising, because last year's 48-horsepower 490 was a jet. A call to our Maico West contacts brought some answers. The new airbox is larger than last year's, but the intake opening is so close to the seat base that airflow is restricted. The Maico West representative suggested cutting away the upper portion of the airbox to increase flow; then the stock jetting would be spot-on. We prefer not to modify any test bike because the consumer's machine will be just like our non-modified unit. In this case, however, the stock 490 performed so poorly that it would have been useless to test the bike without the modification; we would have learned nothing about the new Maico's powerband.
A small bit of X-acto-knife surgery opened up the plastic airbox, and though the change was impressive—the 490 pulled much harder, especially through the mid-range—the Maico still gave up a small lead to both the Husky 430 and the Yamaha 490 in a race to the first turn. Properly set up, the Maico has muscle - but don't expect to bully the opposition with raw horsepower.

Our dyno test figures back up these riding impressions. The 490 Alpha 1 produced less horsepower all through the rev range than last year's 490, and the Yamaha and Husky each hold a strong advantage over the new Maico. Although the Yamaha's mid-range horsepower figures match the Maico's numbers almost exactly, the YZ490 makes about five ponies more than the new 490 down low and on the top end. The lightweight 430 Husky, in turn, holds an advantage in low-end and mid-range power, which is the useful portion of the powerband; nobody keeps an open-classer wound out to 7000 rpm. So the bottom line is we'd rather have last year's engine and power characteristics.

The Maico's power train does offer several advantages. The Alpha 1's predictable power delivery makes the bike easy to ride; no sudden burst of power will send you sideways unexpectedly. The five-speed gear ratios are well suited to the 490's powerband, and the shift action is excellent: the throw is short, the gear detents engage positively, and the lever has plenty of feel. Although the clutch requires a hefty squeeze at the lever, the multi-plate unit resists heat-induced slipping or drag, and clutchless upshifts or downshifts are problem-free.
 

 

Starting any big single can be difficult, but the Maico starts "fairly easily — if you follow the proper drill. First, open the reserve-equipped petcock and tickle the Bing until gas overflows freely. Next, actuate the cylinder-mounted compression release and keep it open until the engine starts; the release lowers cylinder pressure enough to facilitate piston travel over TDC but not enough to prevent combustion. The kickstart lever is mounted high and on the left side, so it's best to kick the engine over with your right foot while you stand beside the bike. A healthy kick with a booted foot almost always lights off the 490, hot or cold, within three tries.

The first time you set out on your new Alpha t, you'll recognize some Maico idiosyncrasies. First, you'll note that the hard, barrel-shaped Magura grips should be replaced immediately with any after-market grip. Second, if you don't keep your trial run short you'll have trouble with the wheels; Maicos are notorious for having spokes work loose, especially up front. Check and tighten the spokes often during the extended bedding-in period or you'll surely break some or flat-spot the Akront rims.

The first time we landed the 490 after a sailing jump, we headed straight for the pits, sure that the handlebar clamps were loose and the bar was shifting down under impact. Wrong. Close inspection revealed that the rubber-mounted bar assembly was flexing slightly as the bike hit down heavily. Some testers objected to the handlebar "give" though they knew the cause; others didn't.

We can both praise and fault the 490's exhaust pipe. Complaints first. The most serious concerns the inadequate exhaust pipe/fuel tank clearance. Both the tank and pipe are free to move around slightly; consequently, the raised seam on our bike's upswept pipe melted a small groove into the tank. By taping a couple of shop towels onto the frame backbone, we raised the tank off the pipe (a lazy but effective fix). The hot exhaust pipe also intrudes on knee space when
the rider slides up on the tank in turns. And the clamp that joins the silencer and pipe was forever loosening and letting the muffler rattle around. A stainless steel hose clamp will fix this last shortcoming.

Now praise. The muffler can be rebuilt, so you can replace the fiberglass packing when it gets oil-saturated or blown out. The big improvement in the 1982 pipe is its mounting system; last year's Mega 2 was plagued with fractured pipe mounts. No fractures this year.

Other small but important improvements to the 490 include a new, easy-to-grasp gas cap. Though the old-style Maico caps sealed well, they were difficult to remove. A new, more substantial roller-equipped chain guide is bolted to the swing arm, and the rear brake is now full-floating. The rear end doesn't chatter or hop while braking, but the rear brake offers little in the way of feel or power; only a healthy tromp on the brake pedal gets the rear brake working hard. In addition, both the brake pedal and shift lever become slippery when wet or muddy. Fortunately, the front brake is better than the rear; although it too requires a moderately firm squeeze for maximum stopping power, its feel and progressive action are excellent.

Maintenance chores with the Maico 490 are easy and few. The Motoplat ignition system has no points to adjust or wear; only the easy-to-reach spark plug needs regular attention. The Alpha 1 carries a new set of chain adjusters, making chain maintenance simpler than it was last year. To get to the air filter takes removing only two bolts and the seat. An ingenious wire-rod retaining system holds the filter in place with spring tension; it removes in two seconds.

The filter itself is a good Twin-Air foam element that should be durable and effective. If you cut away the airbox according to our unofficial fix, you may want to pop-rivet a piece of sturdy wire mesh in place to keep out large dirt clumps. In wet weather, tape over this accessory air duct to prevent the engine from drowning.

Maico motocross machines have always been expensive and they still are: the 490 Alpha 1 costs about $400 to $500 more than most other current big-bore motocrossers. However, there's never been any doubt that you can win at the local level on a Maico if you are up to the task; a quick visit to the winner's circle at any track in the country provides concrete proof.