Author Topic: Honda VT 500FT Ascot  (Read 21858 times)


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Honda VT 500FT Ascot
« on: August 19, 2013, 04:12:10 pm »
There are a lot of ways to look at a motorcycle's performance, and in the rush to record elapsed time, top speed, mileage, braking distance, comfort, whatever, it's easy to overlook Fun.

Fun. All it takes is a ride on the Honda VT500 Ascot to remember how important Fun is.

But first, an identity problem. Make that two identity problems.

One, the Ascot VT500 is named for Ascot Park, a California track where countless legends have been born. Team Honda races at Ascot and has won there. But they don't do either there with the Ascot VT500. For TT, Honda runs a special-framed version of the XL600 Single. For the half mile, the factory uses the CX500-based NS750 or the Shadow 750-based RS750. Despite what the innocent may think they've seen on TV, the VT500 is not a racer, nor is it related to the racers.

Two, there's the Ascot VT500, as seen here, and the Ascot FT500, the same styling but with the XL500-de-rived air-cooled, chain drive Single, that is, two different bikes with a name in common. Next to the Ascot VT500 is the Shadow VT500C, which shares engine and drivetrain with the VT500 Ascot but looks like the VT750C Shadow, which in turn has a water-cooled V-Twin similar in principle but different in nearly every detail from the VT500 V-Twin.

Confusing. There will not be a quiz, but for the sake of brevity, in this text references to the Ascot will mean the VT500 version, ditto for the V-Twin, unless otherwise noted.

Luckily for us all, the styling department has done a more tidy job with this bike. With its small gas tank, flat seat, integrated side panels and sleek tail section, the Ascot looks like a track bike, in the blazing red shown here or is it related to the racers. the optional nearly black blue.

The engine is as successful and as interesting. The VT500 is off the same drawing board as the VT750, although there are no shared parts.

A 90° Vee has natural balance. A 45° Vee is compact and has an, um, traditional look. Honda and Yamaha are busily reinventing the V-Twin and both are looking for ways to get good balance and traditional compactness. Yamaha is using 70° Vees and going to counterbalances when the engine is designed to rev beyond traditional speeds. The Ascot has a 52° angle between the cylinders, not for vibration control.

Honda's cure for imbalance is development of another idea, the offset crankpin. Har-ley, Ducati, Moto Guzzi and Yamaha Vees have both connecting rods on the same throw. The fore-and-aft Honda Vees have a throw (pin) for each cylinder, spaced according to a formula that makes the connecting rods and pistons think they're spaced more widely than the cylinders are. They're also spaced side by side and that introduces another source of vibration, the rocking couple, but as we'll see Honda's solution is workable if not perfect. The crankshaft itself is a one-piece forging, with plain bearings and two-piece connecting rods.

There's more innovative engineering in the cylinder heads. To start with, the Ascot has three valves, two intake and one exhaust, packed into a heart-shaped combustion chamber. The shape would push a single spark plug off center, so to speak, so there are two plugs per cylinder. Lighting the fire two places at once shortens flame travel and that means the engine will tolerate a high compression ratio with so-so fuel and moderate spark advance. We sort of hoped for a Twin version of the radial four-valve heads on the new Honda Singles, but the factory reps say the two engine families are done by separate design teams. But, as with the offset crankpins, the three-valve, two-plug head gives good results. The heads are low, rather than no, maintenance: the single overhead cam works the valves via rocker arms and clearance is adjusted with screw tappets. The timing chains tension automatically.

Top gear in the six-speed box is 0.931:1, i.e. speeds up the output shaft, allowing Honda to fit another one of those "OD" lights on the instrument panel. Final drive is shaft, with the usual bevel gears.

The Ascot's two 32mm Keihin CV carbs are linked to a single push-pull throttle drum and are fed by a horn-shaped chamber which fits between the frame backbone tubes and connects the carbs to an under-seat airbox and filter. The exhaust pipes both exit on the right side of the engine and meet in an expansion box under the swing arm pivot, in front of the rear wheel. Exhaust gasses exit through a single, large muffler. The exhaust is finished in black chrome.

The frame is round steel tubing with dual front downtubes and twin backbone tubes. The steel swing arm runs in tapered roller bearings and is rectangular box-section on the right and round on the left, since the left side encloses the driveshaft. There are two rear shock absorbers with adjustable preload.

The leading axle forks have 37mm stanchion tubes and individual air caps. There's a forged aluminum brace bolted between the two sliders, and the lower triple clamp is steel.

The upper triple clamp is forged aluminum, and the steering stem rides in ball bearings.

The tall, narrow radiator mounts between the frame downtubes and a compact electric fan sits behind it. A section of the right downtube unbolts to ease engine removal and installation, but doesn't carry coolant as similar tubes do in some Hondas. Instead, metal tubes and rubber hoses link the cylinders with the water pump and radiator.

The headlight is rectangular, and a plastic cover just below the headlight hides the single horn. The handlebars are short, with little pullback. The instruments are housed in a square-edged panel. There's a mechanical 120-mph speedometer with odometer and re-settable trip meter, a mechanical 10,000-rpm tachometer (redline is 9500 rpm), a coolant temperature gauge, warning lights for oil pressure and taillight failure, and indicator lights for turn signals, neutral, high beam and OD. The ignition switch and fork lock is mounted with the instruments, while the choke control lever is built into the left handlebar control pod.

Wheels are ^


Honda's pressed-together combination of a cast aluminum hub and spokes and a hollow, extruded aluminum rim. The front wheel is 2.15 x 18 in., the rear wheel 2.50 x 18 in., carrying a Bridgestone 3.50-18 L303 and a Bridgestone 4.25-18 G504 respectively. The single front disc brake has a twin-piston caliper. The rear brake is a mechanical drum.

The Ascot is in the hunt, especially if factors like retail price and ease of service are added to the equation.

There's more to the Ascot than numbers and some of what goes beyond numbers appears contradictory. Vibration. True, vibration is relative. Ride the Ascot after time on a Really Big Twin and the little Vee is smooth as a baby's cheek. Ride the Ascot after time on a Nighthawk 550 and the Twin feels like the washing machine sounds when one leg falls off and the washer starts running around the garage.

Back in class, the Ascot is normal for its type and size. Ever since the invention of the internal combustion engine there have been certain laws and limits, as in one cylinder is more difficult to balance than two, two are more difficult than four, etc. Cylinders have been put in different places; side by side, in a variety of Vees, opposed to each other. There have been counterweights, rubber mounts, opposing crank pins, shared pins and now offset pins.

All of which has come to prove that what matters most are the size of the pistons and the state of engine tune. The VT500 doesn't shake things off, it doesn't blur the mirrors.

We rather like the sensation. Lets you know it's an engine. Good vibes, as they used to say. At the same time, despite no scientific measurement, we suspect that the Yamaha's low-stress Virago 500 and counterbalanced Vision 550 vibrate a bit less.

Because Honda offers all those other models 250 and 600 Singles, 450 and 650 Twins, Twins with automatic transmissions and Twins with turbochargers, right down to the Shadow VT500C, the same internals in a different body, Honda gets to make the Ascot VT500 a definitely single purpose machine.

That purpose is sport. The seat is firm and sloped to keep the rider snug against the tank. The bars are narrow and low. The pegs are high. There is only only riding position, borderline cramped, adding an immediacy and slightly frantic quality to the rider's position, the same sort of no-frills quick-response seat and controls relationship found on a racebike.

the saddle, with a 2.5-gal. gas tank and that narrow-narrow engine. There isn't a lot of mass before the rider's eyes. Maybe it's a case of out of sight, out of mind, but convincing an Ascot rider of the hard facts is difficult unless that rider mans the tape measure and scale himself.

The Ascot isn't the most comfortable motorcycle in the highway, mainly because of the seating position. The suspension plays a role here, too, being tailored for sporting use and also being non-adjustable except for shock preload and fork air pressure within the range of 0 to 6.0 psi. The forks work well enough, but the shocks are not as compliant as we'd like over small bumps in the road surface, and that's a compromise forced upon a sporting bike without adjustable suspension.

Oh, yes. Suspension. We nearly forgot to mention the shaft drive. We nearly forgot because it's not noticed. The Ascot doesn't leap up under power or crouch when the throttle is rolled back. The engineers have used the correct swing arm length and swing arm pivot position and tuned the suspension damping to achieve what the others have said couldn't be done. Okay, the Ascot doesn't have great fistfuls of power and that helps not create driveshaft symptoms, but even so, the only time the Ascot's drive-shaft comes to mind is when the chain doesn't need lube.

Cornering clearance is excellent and the rider has to work to drag the early-warning footpeg "feelers," which extend downward from the ends of the high, folding footpegs. The bike is stable in a straight line and in all sorts of corners. About the most distressing thing it ever does is hop the rear wheel slightly if the throttle is chopped going into a sharp corner.

Out on country roads the Ascot is at home, the rider busy running up and down the gears and setting up for this corner or that. It will pull at low rpm and plonk through city traffic, but the Ascot is happiest reaching for the red-line, making good power over 6000 rpm and best power be-

tween 7000 rpm and redline at 9500 rpm.

The Ascot reached 104 in the half mile and is geared for 107 at redline in 5th gear, which is the gear used for the top speed runs. Sixth, which Honda calls overdrive, would be good for 123 at redline if the engine had the power to pull it, which it doesn't. The advantage of that tall top gear is that the engine spins slower at cruising speeds, as in 4600 rpm at 60 in top.

Just as the Ascot feels lighter than it is, so does it feel more powerful than it is. This isn't a complaint, because the bike is certainly fast. Instead, it's surprising when cruising at speed to arrive at a grade or meet a headwind, reach down for more throttle and discover there isn't as much left as you thought: oh yeah, it's only a 500.

There are some genuine complaints. The key switch is recessed below the instrument panel and it's awkward to reach with gloved hands. The tank is smaller than it looks because of the wide tunnel needed for the hose from carbs to air box. Some of the crew didn't like the bend of the bars although because they're conventional style they can be swapped. The slick rear side panels shield the frame tubes so there's no place to attach luggage. (The grab handles recessed into the panels have tiny studs for bungee hooks, but that's not enough.)

Passenger accommodations are impossible. The muffler is high so the passenger pegs are higher still. The rear portion of the seat is thin and short. It's legal but barely possible for a human being to perch there.

And now, the intangibles. The Ascot VT500 isn't the bike raced at Ascot. Honda's offset crankpins don't undermine the laws of physics. The suspension is stiff and the riding position cramped.

But the handling is crisp, the controls delightful and the engine responsive beyond its numbers. The Ascot is quick and sure and rewarding. The hype and compromises somehow fade away.

The Ascot is fun. B!

Source Cycle World 1983

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« Last Edit: August 19, 2013, 04:40:03 pm by J6G1Z »