25
TECHNICAL DATA
170
25.1
Engine
Design
1-cylinder 2-stroke gasoline engine, water-cooled, with mem-
brane inlet
Displacement
249 cm³ (15.19 cu in)
Stroke
72 mm (2.83 in)
Bore
66.4 mm (2.614 in)
Crankshaft bearing
1 grooved ball bearing/1 roller bearing
Conrod bearing
Needle bearing
Piston pin bearing
Needle bearing
Pistons
Aluminum cast
Piston rings
2 half keystone rings
X (upper edge of piston to upper edge of cylinder)
0… 0.10 mm (0… 0.0039 in)
Primary transmission
26:72
Clutch
Multidisc clutch in oil bath/hydraulically activated
Gearbox
6-gear, claw shifted
Transmission ratio
First gear
13:32
Second gear
16:30
Third gear
16:24
Fourth gear
23:28
Fifth gear
23:23
Sixth gear
26:20
Ignition
Contactless controlled fully electronic ignition with digital igni-
tion adjustment, type Kokusan
Ignition point (BTDC)
1.9 mm (0.075 in)
Spark plug
NGK BR 7 ES
Spark plug electrode gap
0.60 mm (0.0236 in)
Starting aid
Electric starter
25.2
Engine tolerance, wear limits
Piston - diameter
Size I
66.355… 66.365 mm (2.6124… 2.61279 in)
Size II
66.366… 66.375 mm (2.61283… 2.61318 in)
Cylinder - drill hole diameter
Size I
66.400… 66.412 mm (2.61417… 2.61464 in)
Size II
66.412… 66.425 mm (2.61464… 2.61515 in)
Piston/cylinder - mounting clearance
New condition
0.035… 0.060 mm (0.00138… 0.00236 in)
Wear limit
0.10 mm (0.0039 in)
Piston ring - end gap
Ring 1
≤
0.40 mm (
≤
0.0157 in)
Ring 2
≤
0.40 mm (
≤
0.0157 in)
Cylinder/cylinder head - distortion of sealing area
≤
0.10 mm (
≤
0.0039 in)
Connecting rod - axial play of lower conrod bearing
0.60… 0.70 mm (0.0236… 0.0276 in)
Crankshaft - run-out at bearing pin
≤
0.03 mm (
≤
0.0012 in)
Clutch facing disc - thickness
≥
1.9 mm (
≥
0.075 in)
Clutch spring - length
≥
38.0 mm (
≥
1.496 in)
Contact surface of clutch facing discs in outer clutch hub
≤
0.5 mm (
≤
0.02 in)
Shift shaft - sliding plate/shift quadrant clearance
0.40… 0.80 mm (0.0157… 0.0315 in)
