Maico 490 Alpha 1
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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.
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. |