APRILIA TUONO V4 R 2010 Service Station Manual page 238

Engine
key:
1. rear left cylinder;
2. front left cylinder;
3. rear right cylinder;
4. front right cylinder.
Combustion sequence:
1 - 3 - 2 - 4
Combustion angle:
cyl 1: 0°
cyl 2: 180°
cyl 3: 425°
cyl 4: 605°
ENG - 238
TUONO V4 R