Miles-Motors TT-Racer 700 based on Yamaha SR 500

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Miles-Motors TT-Racer 700 based on Yamaha SR 500

Miles-Motors TT-Racer 700 based on Yamaha SR 500
Precious drops

With more volume and unusual ingredients, Yamaha’s SR 500 Single should reach full maturity as the TT-Racer 700.

Gerfried Vogt

04/06/2000

A motorcycle cannot be single-cylinder and four-stroke enough? since Yamaha 1976 with the XT 500 on »back to the roots ?? set, this sentence applied not only to fiery Italians and oily Brits, but also to current bikes from Japan. Quite simply, the XT was soon a hit, the street version offered since 1978 SR 500 became even bigger. In Japan, the bike sold there as the SR 400 quickly became a cult object, but in Germany too, countless companies were soon trying to get the no-frills single. But those who wanted to help the engine professionally on the jumps often burned their fingers, because the stability of the actually simple engine was (and is) not that easy to get under control.
The fact that the heavily dusty construction has not been built since this year has no bearing on the work of the two business owners of Miles Motors, Sabine and Michael Michiels. Because the SR frame required for a freshly built Miles bike cannot and must not be younger than the year of construction 1989. From that year, new noise regulations curtailed the robust half-liter engine, and the 80 dB (A) valid from 1990 onwards could not be met by the 60 hp Miles engines.
Sabine’s motorcycle career also began on an SR 500. Together with her boyfriend, who was still a FZR 1000 driver at the time, she went looking for horsepower five years ago. Fortunately, screws were not new territory for Michael as a master car mechanic. When the SR tuning started to be successful and soon they weren’t just serving friends and acquaintances, “dat just started rolling ??, as the now married couple explains.
The newly rebuilt star, the 700 TT-Racer, is just about to start rolling. Compression 10.5 instead of 9: 1 ?? starting the bike trimmed for British Clubman single shouldn’t be a problem. After a successful OT search, kick a few times with smack? you think, tight calves are required here until the forged piston starts moving by itself in the 100 millimeter larger bore. When you first couple the clutch and shift gears, thoughts of leisurely motorcycle hikes fly away, because instead of the standard pegs, the feet rest here on an LSL aluminum peg system. And the 200 cc extra displacement make the single cylinder significantly more powerful than the standard single from 2500 tours. Highway speed is reached in no time? Third gear is sufficient because of the long 17/40 secondary ratio.
If the chassis is not overwhelmed with this engine power, every sensible SR driver will surely ask himself now. After all, the single-loop frame is not exactly one of the most stable. But don’t worry, the Michiels have taken precautions with progressively wound fork springs and precise bearings on the steering head and swing arm from specialist Emil Schwarz from Schorndorf. The SR 500’s Achilles’ heel, the rapidly wearing swing arm mounting, seems to have been eradicated, the rear wheel moves without a life of its own. Annoying rocking of the rear of the vehicle over long bumps counteract two “progressive suspension struts”, which keep the rear tire on course with quite good damping.
And in order to be able to really enjoy the power of the engine, especially in fast corners, the TT-Racer rolls on 110 and 140 wide tires. So that really weird things can be organized with it, Michael Michiels had a specially developed stainless steel elbow bent to which the short but effective VA silencer hangs. It hides a Supertrapp damping system tailored to the 700 engine using fire-proof sewn insulating material and twelve baffle plates.
The successful coordination of the braking system ensures clear safety reserves. A Kawasaki GPZ handbrake pump, the double disc brake on the front wheel and steel braided lines from Fischer in conjunction with the two lush 290 millimeter discs give the SR driver a completely new deceleration experience. This is also necessary, because the top speed of 176 km / h noted in the certificate can hardly be doubted after various turns on the whisk.
The crucial question: does the engine last? Miles Motors worked for a long time on the utility model-protected strain relief of the cylinder with a separate base plate on the cylinder base and special screw connections. Of course, the engine ventilation has also been adjusted accordingly. Fine ingredients such as Carillo connecting rods, JE forged pistons and TRC camshafts give hope, and a year warranty with unlimited mileage creates trust. »Such high quality parts have never disappointed me ??, explains Michiels while meticulously assembling the next 700s single ?? and answers patiently on the phone again to the question of whether the Miles SR engine has been drilled out.

Technical data – Miles-Motors TT-Racer 700 based on SR 500

Engine: Air-cooled single-cylinder four-stroke engine, an overhead, chain-driven camshaft, two valves per cylinder, Carillo connecting rod, dry sump lubrication, a Mikuni flat slide carburetor, diameter 40 mm, contactless CDI ignition, kick starter, three-phase alternator 167 watts, 12V battery / 7 Ah bore x stroke 100x 88 mmHub volume 691 cm³Compression ratio 10.5: 1Nominal output 44 kW (60 HP) at 6500 / minMax torque 63 Nm (6.4 kpm) at 4600 / minPower transmission: primary drive via straight-toothed gears, multi-disc Bamett oil bath clutch , Five-speed gearbox, O-ring chain Chassis: Powder-coated single-loop frame made of tubular steel with split beams, telescopic fork, standpipe diameter 35 mm, two-arm swing arm made of tubular steel, two spring struts at the rear, double disc brake at the front, 0 290 mm, drum brake at the rear, 0 150 mm, Daytona aluminum tank spoke wheels 3.00 x 18 front, 3.50 x 18 rear Tires 110 / 80-18, 140 / 80-18 Chassis data: wheelbase 1405 mm, steering head angle 63 °, caster 105 mm, Suspension travel front / rear 150/110 Weight 179 kg (dry) Tank capacity 17 liters Price: 23950 Mark Manufacturer: Miles Motors, Im Venn 12, D-41844 Wegberg, Tel./Fax 02434/25358, miles-motors gmx.de

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