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KTM (690 Enduro EU, 690 Enduro AUS/UK, 690 Enduro USA). Manual - part 15

30/ENGINE - WORK ON INDIVIDUAL PARTS

117

19.10

Measuring axial clearance of crankshaft and balancer shaft

300126-10

– Insert the crankshaft and balancer shaft in the right engine casing.

Info

Do not forget the dowels.

– Mount the left engine casing.
– Mount and tighten the screws.

Guideline

Screw, engine case

10 Nm (7.4 lbf ft)

– Mount the dial gauge support on the engine case and measure and note the axial

clearance of the crankshaft.
Guideline

Crankshaft - axial clearance

0.15… 0.25 mm (0.0059…
0.0098 in)

» If the measured value does not equal the specified value:

– Remove the crankshaft.
– Remove the crankshaft bearing inner ring. ( p. 114)
– Calculate the thickness of the compensation shims.
– Add or remove compensation shims equally on both sides.

Info

If the axial clearance is too small, remove compensation shims.
If the axial clearance is too large, add compensation shims.

– Install the crankshaft bearing inner ring. ( p. 116)

300164-10

– Mount the dial gauge support on the engine case and measure and note the axial

clearance of the balancer shaft.
Guideline

Balancer shaft axial clearance

0.05… 0.20 mm (0.002… 0.0079 in)

» If the measured value does not equal the specified value:

– Remove the balancer shaft.
– Calculate the thickness of the compensation shims.
– Add compensation shims to the ignition side only.

Info

If the axial clearance is too small, remove compensation shims.
If the axial clearance is too large, add compensation shims.

19.11

Cylinder - Nikasil

coating

300099-10

Nikasil

is a surface protection layer for a coating method developed by the Mahle

company. The name is derived from the two materials used in this method - a layer of
nickel, in which silicon carbide (a particularly hard substance) is embedded.
The most important advantages of the

Nikasil

coating are the excellent heat conduc-

tivity resulting in better performance, less wear, and low cylinder weight.

30/ENGINE - WORK ON INDIVIDUAL PARTS

118

19.12

Checking/measuring the cylinder

300102-10

– Check the O-ring of the chain adjuster for damage and wear.

» If there is damage or wear:

– Replace the O-ring.

– Check the cylinder bearing surface for damage.

» If the cylinder bearing surface is damaged:

– Change the cylinder and piston.

– Measure the cylinder diameter at several places in the



and



axes using a

micrometer to check for oval wear.

– To determine the size, measure the cylinder at a distance



from the top edge of

the cylinder.
Guideline

Distance



55 mm (2.17 in)

Cylinder - bore diameter

Size I

102.000… 102.012 mm (4.01574…
4.01621 in)

Size II

102.013… 102.025 mm (4.01625…
4.01672 in)

300103-10

– The cylinder size



is marked on the side of the cylinder.

400376-10

– Check the sealing area of the cylinder head for distortion using a straight edge and

the special tool.

Feeler gauge (59029041100) (

p. 214)

Cylinder/cylinder head - sealing area
distortion

≤ 0.10 mm (≤ 0.0039 in)

» If the measured value does not equal the specified value:

– Change the cylinder.

19.13

Checking/measuring the piston

400484-10

– Use the special tool to measure clearance



of the piston rings in the piston ring

groove.
Guideline

Piston ring - groove clearance

≤ 0.08 mm (≤ 0.0031 in)

Feeler gauge (59029041100) (

p. 214)

» If clearance



is larger than the specified value:

– Change the piston and piston rings.
– Check/measure the cylinder. (

p. 118)

300099-10

– Check the piston bearing surface for damage.

» If the piston bearing surface is damaged:

– Change the piston and, if necessary, the cylinder.

– Check that the piston rings can move easily in the piston ring grooves.

» If the piston ring is stiff:

30/ENGINE - WORK ON INDIVIDUAL PARTS

119

– Clean the piston ring groove.

Tip

Use an old piston ring to clean the piston ring groove.

– Check the piston rings for damage.

» If the piston ring is damaged:

– Change the piston ring.

Info

Mount the piston ring with the marking facing upward.

– Check the piston pin for discoloration or signs of wear.

» If the piston pin has strong discoloration/signs of wear:

– Change the piston pin.

– Insert the piston pin into the connecting rod and check the bearing for play.

» If the piston pin bearing has too much play:

– Change the connecting rod and the piston pin.

301758-10

– Measure the piston at the piston skirt, at right angles to the piston pin, at a dis-

tance



Guideline

Distance



31.5 mm (1.24 in)

Piston - diameter

Size I

101.955… 101.965 mm (4.01397…
4.01436 in)

Size II

101.965… 101.975 mm (4.01436…
4.01476 in)

Info

Piston size



is marked on the piston head.

19.14

Checking piston ring end gap

300098-10

– Remove the piston ring from the piston.
– Place the piston ring in the cylinder and align it with the piston.

Guideline

Under the upper edge of the cylinder

10 mm (0.39 in)

– Measure the end gap with a feeler gauge



Guideline

Piston ring end gap

Compression rings

≤ 0.80 mm (≤ 0.0315 in)

Oil scraper ring

≤ 1.00 mm (≤ 0.0394 in)

» If the end gap is more than the specified value:

– Check/measure the cylinder. (

p. 118)

» If the cylinder wear is within the tolerance range:

– Change the piston ring.

– Mount the piston ring with the marking facing toward the piston head.

30/ENGINE - WORK ON INDIVIDUAL PARTS

120

19.15

Checking piston/cylinder mounting clearance

– Check/measure the cylinder. (

p. 118)

– Check/measure the piston. (

p. 118)

– The smallest piston/cylinder mounting clearance is the result of the smallest cylinder bore diameter minus the largest piston diam-

eter. The largest piston/cylinder mounting clearance is the result of the largest cylinder bore diameter minus the smallest piston
diameter.
Guideline

Piston/cylinder - mounting clearance

New condition

0.035… 0.060 mm (0.00138… 0.00236 in)

Wear limit

0.10 mm (0.0039 in)

19.16

Checking oil pumps for wear

Info

The oil pump wear check shown here is on the suction pump but it applies to all oil pumps.

300106-10

– Use a feeler gauge



to measure the play between the external rotor and the

engine case as well as between the external rotor and the internal rotor.

Oil pump

Clearance between external rotor
and engine case

≤ 0.20 mm (≤ 0.0079 in)

Clearance between external rotor
and internal rotor

≤ 0.20 mm (≤ 0.0079 in)

Axial clearance

0.04… 0.08 mm (0.0016…
0.0031 in)

» If the measured value does not meet specifications:

– Change the oil pump and, if necessary, the engine case.

19.17

Replacing autodecompressor

300107-10

– Take the lock ring



off the autodecompression shaft and dispose of it.

300108-10

– Pull the autodecompression shaft



from the camshaft.

300109-10

– Disconnect the autodecompression spring. Loosen the screw



and remove it

together with the autodecompression spring and the autodecompression weight



30/ENGINE - WORK ON INDIVIDUAL PARTS

121

300110-10

– When assembling, first connect the autodecompression spring and then insert the

screw through the autodecompression weight.

The arm of the autodecompression spring



is long enough to pass right

through the autodecompression weight.

– Position the autodecompression weight. Mount and tighten screw



. Reconnect

the autodecompression spring.
Guideline

Screw, autodecompression M6

3… 4 Nm
(2.2…
3 lbf ft)

Loctite

243™

– Mount the autodecompression shaft in the camshaft. Install a new lock ring.
– Check the functioning.

» If the autodecompression spring does not completely retract the autodecom-

pression shaft:
– Replace the autodecompression spring.

19.18

Preparing timing chain tensioner for installation

200171-10

– Fully compress the timing chain tensioner.

Info

This requires considerable force since the oil has to be pressed out.

– Release the timing chain tensioner.

Without pressure, the timing chain tensioner expands fully.

200172-10

– Place two spacing washers or similar aids next to the piston of the timing chain

tensioner. This should ensure that when pushed down, the piston does not fully
withdraw.
Guideline

Thickness of spacers

2… 2.5 mm (0.08… 0.098 in)

– Release the timing chain tensioner.

The latching system locks and the piston stops moving.

End position of piston after latching

3 mm (0.12 in)

Info

This position is necessary for installation.
If the timing chain tensioner is now pressed in once more (while it is
installed) and then pulled out no more than halfway (preventing it from
coming out fully), the latching system locks and the timing chain tensioner
can no longer be compacted; this function is necessary to ensure sufficient
tension of the timing chain, even at low oil pressure.

30/ENGINE - WORK ON INDIVIDUAL PARTS

122

19.19

Checking timing assembly

300113-01

– Clean all parts well.
– Check the timing chain gear / timing chain sprocket



for damage and wear.

» If there is damage or wear:

– Replace the timing chain gear / timing chain sprocket.

– Check timing chain tensioning rail



for damage and wear.

» If there is damage or wear:

– Change the timing chain tensioning rail.

– Check timing chain guide rail



for damage and wear.

» If there is damage or wear:

– Change the timing chain guide rail.

– Check timing chain securing guide



for damage and wear.

» If there is damage or wear:

– Replace the timing chain securing guide.

– Check timing chain



for damage and wear.

» If there is damage or wear:

– Change the timing chain.

– Check that the timing chain links move easily. Let the timing chain hang down

freely.
» If the chain links no longer straighten out:

– Change the timing chain.

19.20

Removing rocker arm

300113-10

– Remove screws



300114-10

– Screw a suitable screw



into the rocker arm shafts



. Pull out the rocker arm

shafts.

– Take off the rocker arm



19.21

Changing camshaft bearing

– Remove the rocker arm. (

p. 122)

300226-10

– Clamp the cylinder head.

Clamping plate (75029050000) (

p. 218)

– Remove the large camshaft bearing using the special tool



Push-out drift (75029051000) (

p. 218)

30/ENGINE - WORK ON INDIVIDUAL PARTS

123

300228-10

– Remove the small camshaft bearing



using the special tool.

Insert for bearing puller (15112018100) (

p. 212)

Bearing puller (15112017000) (

p. 212)

300229-10

– Press in the small camshaft bearing as far as possible using the special tool



Push-in drift (75029044020) (

p. 217)

300230-10

– Press in the large camshaft bearing as far as possible using the special tool



Push-in drift (75029044010) (

p. 216)

– Install the rocker arm. (

p. 126)

19.22

Removing valves

300115-10

– Take the shims



out of the valve spring retainers and lay them to one side accord-

ing to their normal built-in position.

300116-10

– Pretension the valve springs using the special tool.

Valve spring compressor (59029019000) (

p. 213)

Valve spring mounting device (78029060000) (

p. 220)

– Remove valve keys and release tension on the valve springs.
– Remove spring retainers and spring.
– Pull the valve down and out of the valve guide, remove the valve stem seal and

valve spring retainer.

300117-10

– Mark the valves according to their normal built-in position.

Info

Place the valve into a box according to the installation position and label the
box.

30/ENGINE - WORK ON INDIVIDUAL PARTS

124

19.23

Checking valves

200193-10

– Check the run-out at the valve plate.

Valve - run-out

On the valve plate

≤ 0.05 mm (≤ 0.002 in)

» If the measured value does not equal the specified value:

– Change the valve.

400373-10

– Check the sealing seat



on the valve.

Valve - sealing seat width

Intake

1.60 mm (0.063 in)

Valve - sealing seat width

Exhaust

2.00 mm (0.0787 in)

» If the sealing area is not in the center of the valve seat or deviates from the

specified value:
– Machine the valve seat.

19.24

Checking valve springs

300118-10

– Check the valve springs for fractures and wear (visual check).

» If the valve spring is fractured or worn:

– Change the valve spring.

– Measure the valve spring lengths.

Valve spring

Minimum length (without valve
spring cap)

42.3 mm (1.665 in)

» If the measured value does not equal the specified value:

– Change the valve spring.

19.25

Checking valve spring retainer

300162-10

– Check the valve spring retainer for fractures and wear (visual check).

» If the valve spring retainer is fractured or worn:

– Change the valve spring retainer.

– Measure the thickness of the valve spring retainer.

Valve spring cap - thickness

2.4… 2.5 mm (0.094… 0.098 in)

» If the measured value does not equal the specified value:

– Change the valve spring retainer.

19.26

Checking cylinder head

300119-10

– Check the valve guides using the special tool



Limit plug gauge (59029026006) (

p. 213)

» If the special tool is easy to insert into the valve guide:

– Change the valve guide and valve.

– Check the sealing area of the spark plug thread and the valve seats for damage and

tearing.
» If there is wear or tearing:

– Change the cylinder head.

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