24 Series 4144 Powerhead
: Pull the ball bearing (1) off the 
straight crankshaft stub.
The crankshaft (1), connecting rod 
(2) and needle bearing form an 
inseparable unit.
When fitting a replacement 
crankshaft, always install new ball 
bearings and oil seals.
– Before installing, clean the 
crankshaft, b 9
938RA058 TG
1
1
938RA059 TG
2
Use a firm base (2) to protect the 
crankshaft.
: Apply a suitable sleeve (1) to the 
inner race of the ball bearing at 
the carrier side and press it home 
as far as stop.
Use a firm base (2) to protect the 
crankshaft.
: Apply a suitable sleeve (1) to the 
inner race of the ball bearing at 
the ignition side and press it 
home as far as stop.
– Lubricate needle bearings in 
small end and on crankshaft with 
oil.
– Install the piston, b 6.7
– Fit new oil seals and install the 
crankshaft, b 6.5.1
– Install the engine – see service 
manual for "Series 4144 
Components – FS, FC, KM"
938RA060 TG
1
2
938RA061 TG
1
2
– Tightening torques, b 3.3
– Reassemble all other parts in the 
reverse sequence.
6.7 Piston
– Remove the engine – see service 
manual for "Series 4144 
Components – FS, FC, KM"
– Remove the cylinder, b 6.4
The piston has only one snap ring. It 
is fitted at the carrier side (short 
crankshaft stub).
: Use a suitable tool to grip the 
hookless snap ring at the recess 
(arrow) and ease it out.
: Apply assembly drift (1) 
1130 893 4700, small diameter 
first, to the ignition side of the 
piston.
938RA062 TG
1
938RA063 TG