Husqvarna 2011 SMS 630, Workshop Manual

Page: 138 / 455

G.6 Part. N. 8000 H2051 (02-2010)
ENGINE OVERHAUL
Ream the valve guide using a suitable reamer and lubricate with cutting fluid.
Rotate the reamer when extracting it to avoid scoring the valve guide.
When a valve guide is changed, the valve seat must be refaced.
Valve
Inspect valve stem and valve seating face to make sure they are in
good condition. There should be no signs of pitting, cracking, distortion or
wear. Check for the following:
- Valve stem runout: place valve on a V block and measure runout with a dial
gauge. (Service limit: 0.05 mm).
- Valve head out-of-round: place valve on a V block and check with a dial
gauge at right angles to the head while turning the valve. (Service limit: 0.03
mm).
Valve spring
Check free length “L”. If outside the specified service limit,
replace the springs.
Spring: L = 43.4 mm - Service limit: 41 mm
Replace all valve springs whenever any one spring exceeds the
service limit.
Check the valve springs for proper squareness.
Maximum acceptable deviation is 1.5 mm on each side.