The snowmobile turned rough in appearance, but in the winter test showed it good driving performance: throughput, speed; he was compact and lightweight, economical on fuel consumption. The asymmetric arrangement of the engine, of course, has its advantages: easy access for maintenance, ease of launch and gear shift, the possibility of direct chain drive directly on the drive shaft of the caterpillar. However, on loose snow when cornering, the machine was often filled up. This circumstance determined my decision to move the engine to the middle of the front of the snowmobile. Had to modify the design, especially the front end of the frame, and install the intermediate shaft in the drive unit to transmit torque from the engine to the caterpillar. There were other alterations that I implemented during the modernization of the snowmobile, which improved its ride quality, reliability, and comfort (if I may say this utilitarian car), and about them—in the course of the story.
1 — front cross member frame; 2 — front (steel, pipe 28×28): 3 — bearing rudder (area 25×25); 4 — steering shaft (steel, pipe 20); 5 — rail (steel, pipe 28×28); 6 — timer; 7 — washer (bronze); 8 — support sleeve with the area; 9 — nut M10
1 — support of the seat (steel, rough 28×28); 2 — cross frame (steel, pipe 28×28); 3 — front (steel, pipe 18×18); 4 — traverse (area 45×25); 5 — cosina (steel, plate 40×5. 2); 6 — the bearing 204 in the housing (2); 7 — intermediate shaft (steel, pipe 27×3); 8 — sprocket No. 1 (z=21); 9 — longitudinal frame; 10 sprocket No. 2 (z = 17); 11 — a casing (rubber)
1 — coupling with nut M8 (steel, rod d8, 2 PCs); 2 — sprocket crawler block, 3 — drive shaft of the caterpillar; 4 — tensioning device; 5 — tension roll; 6 — truck (rail 500x38x18); 7 —longitudinal frame; 8 — sprocket driven shaft caterpillar; 9 — support skiing; 10 — a bracket of the supporting ski (channel 45x32x3); 11 — болтМ8; 12,13 — bolts M6; 14 — guide (brass); 15 — screw; 16 — a sole reference skis (polyethylene): 17 — fixing the bearing housing; 18— axle tension rollers
1 —ski (plywood s8), 2 – handle (steel, pipe 10×2), 3— front spring (from the seat of the UAZ); 4 — spar (Board s25): 5 — support bracket (corner 25×25, 2 sh.); 6 — fork (steel, strip s5, 7 – steering column (steel, pipe 33×3). 8 — front (steel, pipe 27×3); 9 — rear spring (shock absorber of a motorcycle “Minsk”); 10 — the undercut (area 25×25, L450, 2); 11 —sole (polyethylene s4), 12 – rivet (aluminium, 40 pieces)
1 — ties (steel, rod 08); 2 — suspension bushing; 3 — ski; 4 sole (polyethylene 84); 5 — guide (brass);
The drive shaft of the caterpillar:
1 – sprocket driven (z=37, homemade), 2— bearing housing 3 — bolt M6 (4 PCs); 4 — caterpillar asterisk (plywood s20. 2); 5 — shaft drive axle (steel, pipe 32×4): 6 — flange caterpillar sprocket; 7 — bearing 204; 8 bushing valuable stars; 9 — insert (steel circle)
1 – bolts, nuts and washers; 2 — conveyor rubber belt; 3 — Trak (birch stick); 4 — guide
Sprocket, tensioner rink
The slipway for the Assembly of a caterpillar (a tree)
To install the engine with the subframe in the middle of the car, to the front traverse frame welded platform, making the appropriate holes for the “feet” of the subframe. The same holes made in the next traverse. The holes in the “legs” of the subframe is altered in the longitudinal slot for tensioning the drive chain by moving the engine forward. The seat frame also had to be redone, shifting her back a little. The engine now runs with the help of a homemade arm, not a kick starter, gear shift — as a normal bike.
Before the upgrade, with the side location of the engine had no forced cooling. After moving it to the middle had under the front panel to install the fan with turbine-coy and “snail” from the heater ZIL-157. The inlet is soldered from tinned sheet metal. Part
the spent (heated by engine cooling) of air sent to the carburetor. The gas tank was moved to the body and put it there in the corner stands to the gasoline to the carburetor through a long hose fed still by gravity.
The transfer engine in the middle greatly improved the stability of the machine, which reduces rut of governors of the ski from 1100 to 950 mm, and this, in turn, has improved the maneuverability of a snowmobile, which is especially important when riding in the woods.
The intermediate shaft not only transmits the rotation from the engine to the drive shaft of the caterpillar, but also reduces the angular velocity, increasing torque, as the first sprocket (d = 21) from the gearbox main gear motorized FDD, and the second (g = 17) is a motorcycle “IZH”, from him and drive chain sprocket Driven shaft caterpillar has 37 teeth. The speed of the snowmobile decreased slightly, but the traction has increased significantly. Now the machine can carry two riders, the cargo in the trunk and pull a light homemade sled with baggage. The width of the runners of the sled fits into the track of a caterpillar. Rarely was the speed of the switch — the engine better pull in the higher gears. This was facilitated by the replacement of the drive sprockets of caterpillar tracks on stars of plywood with the same number of teeth (eight), but a smaller diameter.
Such a small improvement is improved and throughput of the machine — the asterisk is still a little raised above the level of the reference ski, which not only eliminated her contact with the road, but also allowed caterpillar to more easily enter the upper layers of snow and more confident to overcome obstacles — snow ridges, bumps, etc.
Operation of the snowmobile before the upgrade, found that the tension shaft caterpillar teeth quite often came on a wooden track. And I made them rollers, cut away all the teeth of the supporting skis, lined with rigid polyethylene, are bent and the rear end. Now the caterpillar is going with skis on rollers smoothly without crackling and almost silently. Improved tension mechanism, making it a spiral.
The caterpillar is also altered. Reducing the distance between the tracks 45 and 38 mm, increased the number to 33 pieces. Truckee sizes 500x38x18 mm made from birch boards without knots and other defects, double-soaked in their hot natural linseed oil. To build the caterpillar made a template of the slipway, which provided not only convenience, but also the accuracy of the installation of tracks on the tape without any distortions.
Upgraded plywood and the front steering skis. First, strengthened their top spars of spruce boards. Secondly, changed dural “sole” on the plastic, making it the same as that of the reference ski. Thirdly, the suspension of the skis introduced spring and now the machine goes soft even in the snow. This increased vitality of not only the skiing but also frames. In-chegworth, angled noses wad attached to the handle of the steel tubes because of them easier to pull out a stuck vehicle (this may happen somewhere in the snow-covered ravines). With the same purpose, a similar arm secured on the pillar.
To protect the rods from damage during the raids on stumps and other snow-covered obstacles ahead of rods mounted UNDER the bumper of plywood.
In addition to these improvements completed and a number of smaller: attached headlight and tail lights, mounted the fairing with the windscreen and turned the seat from scooter “Vyatka” with removable backrest — now not so tired back and does not freeze back.
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