Choosing The Gasket - Derbi GP1 125-250 c.c. Workshop Manual

C
HOOSING THE GASKET
Characteristic
Compression ratio - 125cc version
Re: 11,50 ÷ 13:1
The length «A» to be measured refers to the piston protrusion. It indicates the amount by which the surface formed
by the piston crown tops the surface formed by the upper part of the cylinder. The more the piston descends into the
cylinder, the less the base gasket to be applied (to recover the compression ratio) will be and vice versa.
N.B.
THE MEASUREMENT OF «A» MUST BE CARRIED WITH THE PISTON AT THE TDC, WITHOUT ANY GASKET
INSTALLED BETWEEN THE CRANKCASE AND THE CYLINDER, AND AFTER RESETTING THE COMPARATOR,
COMPLETE WITH SUPPORT, ON A RECTIFIED SURFACE.
125CC VERSION WITH FIBRE HEAD GASKET (1.1)
NAME
Thicknesses 125
Thicknesses 125
113
MEASURE A
÷
2,20 2,45
÷
2,45 2,70
THICKNESS
0,4 ± 0,05
0,6 ± 0,05