Yamaha TDM850 User Manual page 58

10.6b On TRX models, remove the blanking cap, then remove the frame-
to-cylinder head bolt (arrowed) on each side
6 On TDM and TRX models, unscrew the engine
mounting bolts which thread into the cylinder
head on each side (see illustrations). On TRX
models, first remove the caps.
7 Each cylinder head is secured by two bolts,
located in the cam chain tunnel, and six nuts
(see illustration). First unscrew and remove the
bolts (see illustration 10.16). Now slacken the
nuts evenly and a little at a time in a criss-cross
pattern until they are all slack, then remove the
nuts and their washers (see illustration 10.15).
8 Pull the cylinder head up off the block (see
illustration). If it is stuck, tap around the joint
faces of the cylinder head with a soft-faced
mallet to free the head. Do not attempt to free the
head by inserting a screwdriver between the
head and cylinder block - you'll damage the
sealing surfaces. Remove the old cylinder head
gasket and discard it as a new one must be
used.
9 If they are loose, remove the dowels from the
cylinder block. If they appear to be missing they
are probably stuck in the underside of the
cylinder head.
,10 Check the cylinder head gasket and the
mating surfaces on the cylinder head and block
for signs of leakage, which could indicate
warpage. Refer to Section 12 and check the
flatness of the cylinder head.
10.13 Lay a new head gasket over the
dowels (arrowed) and onto the head
Installation
11 Clean all traces of old gasket material from
the cylinder head and block. If a scraper is used,
take care not to scratch or gouge the soft
aluminium. Be careful not to let any of the gasket
material fall into the crankcase, the cylinder
bores or the oil passages.
IJTHJT33 Refer to Tools and
milUSi workshop Tips in the
Reference section for details of
gasket removal methods.
HiWT
12 If removed, install the dowels into the
cylinder block (see illustration 10.13). Lubricate
the cylinder bores with engine oil.
13 Ensure both cylinder head and block mating
surfaces are clean, then lay the new head gasket
in place on the cylinder block, making sure all the
holes are correctly aligned (see illustration).
Never re-use the old gasket.
14 Carefully fit the cylinder head onto the block,
making sure it locates correctly onto the dowels
(see illustration 10.8).
15 Lubricate the threads of the cylinder head
nuts with clean engine oil (if the camshafts are in
place, one or two drops of oil can be squirted
around the nuts into the stud holes). Install the
nuts with their washers and tighten
10.15 Install the nuts with their washers
and tighten them as described to the
specified torque
Engine, clutch and transmission 2»19
10.7 Cylinder head bolts (A) and nuts (B)
them finger-tight (see illustration). Now tighten
the nuts evenly and a little at a time in a criss-
cross pattern to the torque setting specified at
the beginning of the Chapter.
16 Install the two cylinder head bolts and
tighten them to the specified torque setting (see
illustration).
17 On TDM and TRX models, install the engine
mounting bolts and tighten them to the specified
torque setting (see illustrations 10.6a and b). On
TRX models, fit the caps into the bolt heads.
18 Install the oil pipe onto the cylinder head,
using new sealing washers on each side of
10.8 Carefully lift the head up off the block
10.16 Install the bolts and tighten them to the
specified torque
Scaned by Stalker