Aeon 350cc, Service Manual

Page: 63 / 192

ENGINE
4-63
CYLINDER HEAD DISASSEMBLY
Wear eye protection or a face shield during cylinder
head disassembly and reassembly.
NOTE: Keep all parts in order with respect to their
location in the cylinder head.
NOTE: Valves have inner and outer springs.
1. Using a valve spring compressor, compress the valve
springs and remove the split keeper.
NOTE: To prevent loss of tension, do not compress
the valve spring more than necessary.
2. Remove spring retainer and spring.
NOTE: The valve springs should be positioned with
the tightly wound coils against the cylinder head on
progressively wound springs.
3. Push valve out, keeping it in order for reassembly in the
same guide.
4. Measure free length of the inner and outer springs with a
caliper.
Valve Spring Free Length
Outer Spring Limit: 41.5mm
Inner Spring Limit: 31.3mm
5. Check spring for squareness as shown. Replace spring if
measurements are out of specification.
Valve Spring Tilt Limit
Both Spring Limit: 2.5
˚˚˚˚
/ 1.5mm
NOTE: Replace seals whenever the cylinder head is
disassembled. Hardened, cracked or worn valve
seals will cause excessive oil consumption and
carbon buildup.
VALVE INSPECTION
1. Remove all carbon from valve with a soft wire wheel.
2. Check valve face for run out, pitting, and burnt spots.