Rotax 125 Micro MAX User Manual

DK00026.fm
REPAIR MANUAL
BRP-Powertrain
Effectivity: 125 MAX/125 Junior MAX/125 Mini
MAX/125 Micro MAX
Edition 2 / Rev. 0
Chapter 4
Page 35
December 01/2010
4.8) Inspection and adjustment of “squish gap”
General NOTES: The gap between the piston (at the TDC of the piston) and
the combustion chamber insert (= “squish gap”) is partly
responsible for the power and the power characteristics of
the engine.
NOTES: The smaller the squish gap the higher the engine com-
pression. This means that the engine response to the feed
from the carburetor becomes more critical under changing
operating conditions (temperature, air pressure, humidity).
Special tools The following special tools and equipment are required:
Instructions See Figure 24.
NOTES: We recommend setting a squish gap in the upper
tolerance range of the relevant model.
Part number Description Use
Part no. 580130 Solder 2 mm Combustion chamber
Part no. 580132 Solder 3 mm Combustion chamber
n.e Vernier calliper Solder
Step Procedure
1 Rotate crankshaft by hand until the piston is approx. 5 mm below TDC.
2 Right thickness of solder
2.0 mm (for 125 MAX only)
3.0 mm (for 125 Junior MAX only)
bend as shown in the picture and insert through the spark plug thread into the
combustion chamber until the solder is in contact with the cylinder bore.
The squeeze edge must alway be measured in the direction of the axis of the
piston pin. The result of a measurement of the squeeze edge in the direction
of the exhaust port will be falsified by the tilt of the piston and is not approved.
3 Rotate the starter gear assembly by hand over the TDC position.
NOTES: This will crush the solder between the piston and the com-
bustion chamber insert.
4 Remove the solder from the combustion chamber and measure the thickness
(= “squish gap”) of the crushed end of the solder with a vernier calliper.
NOTES: A vernier calliper with an accuracy of 1/100 mm is required
for this measurement.
5 The squeeze edge must be within the specified tolerance
range.
1.05 mm + 0.25 mm (125 MAX only)
1.45 mm + 0.25 mm (125 Junior MAX only)
NOTICE

Rotax 125 Micro MAX Specifications

General

Brand	Rotax
Model	125 Micro MAX
Category	Engine
Language	English