Derbi ATV DXR 200, Workshop Manual

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47
3 31. E
NGINE
A
DJUSTMENT
(F
IG
. 3-55, 3.56, 3-57, 3-58, 3-59. 3-60)
3-31-1. Valve clearance
01- remove the cylinder head cover Fig. 3-55
02. rotate the generator flywheel on camshaft on the top dead centre (TDC) and align the “T” mark. Fig.
3-56, 3-57
03. Valve clearance (IN: 0.05mm EX: 0.05mm) Fig. 3.58
04. adjust by loosening the lock nut and turning adjusting bole
05. after adjustment, turn the crankshaft several rotations to make sure the valve clearance is correct.
CAUTION
1. CHECK THE VALVE CLEARANCE WHILE THE ENGINE IS BELOW 35C.
2. CHECK THE VALVE CLEARANCE AGAIN AFTER THE LOCK NUT IS LIGHTENED.
3-31-2. Ignition timing (15 degree/1,500 rpm)
01. remove the ignition timing hole cap on L crankcase Fig. 3-57
02. use the ignition timing light, to check ignition timing Fig. 5-59
03. the correct ignition timing at idle speed mark on “F” in flywheel
CAUTION
THE CDI IGNITION TIMING IS NOT ADJUSTABLE. IF TIMING IS INCORRECT, CHECK THE IGNITION
SYSTEM.
3-31-3. Cylinder compression (Fig. 3 – 60)
01. warn up engine few min. and then stop engine
02. remove the spark plug and insert the compression gauge.
03. open. the throttle fully and re-start engine
04. measure the compression: 1.3kg/cm2 Fig. 3-60
05. if compression is low, be checked:
1). leaky valve
2). small valve clearance
3). damaged cylinder head gasket
4). worn piston rings
5). worn cylinder and piston
06. if compression is high, be checked:
1). carbon deposits have accumulated on combustion chamber
2). carbon deposits have accumulated’ on the piston head
3-31-4. idle speed adjustment. -- refer to part 3-07