MINI-BIKE STUDENT

This micromatic created a budding Amateur designer — senior Artyom Pokrovskiy from the city of Tver. Creatively using the publication of “Modeller-designer” of yesteryear (in particular, published in No. 2 of’79 and # 8’89), he is from parts, components and assemblies used bikes and mopeds collected miniature vehicle. This car does not need a garage— it can be stored on the balcony of a city apartment, lifting her in the Elevator. Mini dirt bike has a high cross, but rather “portability” — trudnoreshaemyh place can be overcome, taking him in hand (even a child), and then take it further.

Frame mini-bike regular: tubular, trapezoidal (often it is called triangular, not taking into account the short steering column) with an additional strut. It is made of frame road bike, which has undergone little alteration: it was cut off seatpost stand together with the BB node and the adjacent portion of the front pipe. Became unnecessary and the rear fork. New seat tube is set a little steeper and closer to the steering column and under the rear end of the upper pipe summed up the brace (cut the old seat tube). Before you weld the new frame parts, their ends were carefully customized round file for the radius of the abutting pipes. The welding was made on flat ground to all elements of the frame are in the same plane.

After that, the tubes of the frame was welded foot pegs cut from solid tubes and three tube-bushings for axes: upper ends of shock absorbers, pedals, foot brake and fork rear suspension pendulum. Before welding the place mates at the bushings and the tubes of the frame was a little undermined a round file to increase the area of contact between the parts so that they fit snugly to each other, extending the perimeter of the seam. When attaching the foot pegs and bushings must comply with the perpendicular to the plane of the frame. It is especially difficult (but most important) to fulfill this condition when docking the pendulum sleeve, as it attaches to the seat tube using two steel plates.

General view of mini-bike:

1 — power unit with engine D-6; 2 — front fender (part of the wing from the old mini-mokik); 3 — front wheel (from a child’s Bicycle); 4 — front fork (moped “Gazole”); 5 — headlight (from the tractor); 6 — wheel (of a Bicycle “Desna”); 7— fuel tank capacity 2 l (from motorbike); 8 — frame (road bike, converted); 9 — saddle (from moped “Gazole”); 10— tail light (from moped); 11 — rear shock (from a moped “Riga”, 2); 12— rear wing (part of the wing from the old mini-mokik); 13 — rear wheel (from a child’s Bicycle, converted); 14—brake scraper type; in the front view of the front fender not shown

Set mini-bike D-6 engine

Front fork is shortened, from the Riga moped. Feathers plug cut to the dimensions shown in the figure, and their lower ends welded tapered ears brackets as the regular wheel axle from the children’s bike short. The upper part of the lugs before welding is curved to fit the tube elongation of the same axis would entail and the increase in its diameter, and this would lead to undue alteration of the wheel. Even more of a challenge to reduce the distance between the feathers plugs would be the alteration of bridges connecting them, and from this I also refused. Tying feathers to each other, the bridges connect the plug with the rod of the steering column. The rod in the column pivots in two bearings and the cones, taken from the same moped, although it would be possible to leave a Bicycle.

The back of the pendulum fork is made of chain mentioned fork road bike, which was taken frame. Pipe diameter of 22 mm., From feathers plug cut the front tapered part along with the bridge, and left the necessary size of pipe with tips. The slots in the lugs of the fork to the axis of the rear wheels at an angle to the feathers and open front. Such a location will allow you to tighten the chain, but if it is accidental breakage will not let the axle pop out of the plugs. Left tip is slightly twisted to the side of the sprocket wheel. The front ends of the tubes of the feathers tapered, corners rounded, and here the drilled holes with a diameter of 10 mm for axis (from moped). The feathers are connected by a welded bridge of a segment of the same pipe. Around the fork tips to the feathers welded on the brackets for fastening the lower eyelets of the shocks.

Frame road bike

Frame mini-bike:

1 — used part of the road bike frame; 2— front seat (tube 28×2); 3 — brace (cut from a seat tube of a Bicycle); 4— bushing the axis of the upper support of shock absorber (tube 22×3); 5 — bushing rear axle of the pendulum fork (tube 22×3); 6— footboard (pipe 22×3); 7— bracket bushings (St3, sheet z, 2 PCs.)
 

Front fork (shortened, from a moped):

1 — bridge upper; 2 — body of feathers; 3 — lower bridge; 4 — feathers 5 — ears-brackets (St3, sheet s)

Axis in steel grommet installed in the two end rubber bushings, made of silent blocks of the engine mounts V50 moped “Karpaty”. Excess material was removed with ordinary sandpaper, and the holes are bored by a steep bastard file.

Wheel — children’s Bicycle. In the rear wheel spokes replaced with duralumin plates. Eight of them; it is cruciform, four on each side of the wheel (bushing). The holes from under the spokes, intended for fastening of inserts, reamed to a diameter of 4.2 mm., Each plate is attached to the hub with two bolts M4, and the rim — one in the same bolt. To avoid unwinding under the nuts of the supplied washers and the ends of the bolts a little flattened.

Next, one side of the wheel planted on the hub flange and attached to the plates with four bolts M5 drive sprocket. Between the sprocket and the plates installed spacer, and under nuts bolts washers placed slant. The ends of the bolts again a little flattened. Despite artisanal manufacturing, “eights” in the wheel is not observed. Brake scraper type (it’s not). The force from the brake pedal is transmitted through the rigid rod to the pad mounted pivotally on the bridge of the pendulous fork, which is pressed against the tire of the rear wheel.

The power unit with the engine D-6 alterations almost not exposed. Only when installing on the frame the engine is tilted slightly forward, so between it and the carb fitted dural spacer oblique to the axis of the throttle sociopatterns device is located vertically.

The back of the pendulum fork (all the details — from the rear fork road bike):

1 — right-feather; 2 — bridge; 3 — left feather; 4 — left-tip; 5 — right tip; 6 — brackets of shock absorbers
 

Installation of the planks instead of spokes in the rear wheel (from a child’s Bicycle):

1 — hub wheel hub bearing; 2 — bolt M4 (3 PCs. per plate); 3 — plate (duralumin, sheet s); 4 — rim; 5 — rubber ring (from old camera); 6 — spacer; 7 — an asterisk; 8 — M5 bolt; 9— washer oblique

Wiring diagram, miii-bike

Now about the other components parts and components. The wheel from the Bicycle “Desna”. Cables, handles and levers — from mopeds. Both wings are made from a single cut to pieces the rear fender mini-mokik and elongated rubber mud flaps. The front wing is bolted to the lower fork bridge with one bolt. The rear wing is fixed in two places: the front clamp to the brace frame, rear — bolt to the bracket of the signal lamp. Rear shocks — moped “Riga-3”. Tank capacity 2 litres with a tap and a silencer from a motorbike. Saddle from bike.

Onboard — Seliverstova, at this voltage, all bulbs appliances. The headlight from the tractor, it’s the switch. Taillight from the bike. The diagram shown in Fig.

Mini-bike lived up to my expectations: there is a soft, easily controlled. Fuel consumption is small compared with the present motorcycle — around 1.8 l / 100 km. So that the mini-bike I’m happy.

POKROVSKY, G. T V e R s