Derbi ATV DXR 200, Workshop Manual

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67
NOTE
PROBLEMS SHOOTING:
<Q-A> Poor performance at idle speed - compression too low?
- incorrect valve clearance too small
- burned or bend valve
- incorrect valve timing
- broken valve spring
- valve seas not airtight
- leaking cylinder head gasket
- warped or cracked cylinder head
- poorly installed spark plug
<Q-A> Compression to high?
- excessive carbon build-up in combustion chamber or on pinion head
<Q-A> White smoke from exhaust muffler?
- worn or damaged valve stem or guide
- damaged valve stem oil seal
- Worn piston ring
<Q-A> Abnormal noise?
- Incorrect valve clearance; too large
- Burned valve and rocker arm
- Worn camshaft or cam follower
- Worn valve guide
4-4-1. Cylinder head cover removal Fig. 4-42
01. remove the 3 bolts attaching on cylinder head cover
02. remove the cylinder head
03. check the cylinder head cover o-ring, replace it if damage
4-4-2. Rock arm set removal. fig- 4-42, 4-42A
01. remove the 3 bolts
02. remove the rock arm set
03. measure L & R rocker am clearances (a)
*
standard: 0.05-0.25mm
CAUTlON
TURN THE PISTON ON TOP END BEFORE MOVING THE ROCK ARM SET. WHEN REMOVING THE ROCK
ARM SET. LOOSEN THE CENTER BOLS AND THEN L & R BOLT.
4-4-3. Cylinder head removal (Fig. 4-43)
01. remove the intake and exhaust valve push bars
02. remove the cam follower bolts (1)
03. remove cylinder head lock nuts diagonally (2).
04. remove the push bar guide plate (3)
05. remove the cylinder head (4)