3
UPON RECEIVING THE ENGINE
Check external appearance of the box and note any damage, especially any holes caused by
penetration of a sharp object. When signing for a shipment, be sure to
sign it off as “Subject
to Inspection”. In this manner, if there is any damage that was not obvious at the time of
delivery, you will usually have a couple of days to make a damage claim to the carrier.
Check that the engine and equipment, etc. have not sustained any damage. If damaged, make
written note. A photograph of the damage is desirable, not only of the damaged piece but
photos of the box and packaging.
Take care not to touch carburetor adjustments just yet. Carburetors are adjusted at the
factory to a point where the engine will start; yet not overspeed providing that an adequate
propeller is installed.
FORWARD
Congratulations on your purchase of a new Hirth engine! If properly installed and
maintained, you should receive many years of reliable service from the engine.
Description: The engine F-23 of Hirth Motoren GmbH & Co. KG is an air-cooled, Piston
port-controlled opposed two-cylinder 2-stroke-engine. The cylinder consists of an aluminium
alloy with wear-resistant tread alloy. Each cylinder is mounted to crankcase with 4 threaded
studs secured with hexagon head nuts. The cylinder head consists of a special aluminium
alloy that retains the same temper/ hardness in high temperatures. It is attached to cylinder-
by-cylinder screws and does not require a head gasket. The piston consists of an aluminium
alloy and is centered by two piston rings expanding against the cylinder wall. The piston is
attached to the connecting rod by piston pin and needle bearing. The crankshaft consists
Chrom-Molybdän-Steel (42 Cr Mo 4) and is mounted in 3 ball bearings. It conforms to what
is known as a manufactured or segmented crankshaft. The output drive is conical and
equipped with centric external thread for mounting a junction cone on output drive. The
connecting rod is connected with/linked to the crankshaft through a crankpin and a needle
bearing. The crankcase consists of an aluminium alloy. It is constructed as a divided case and
consists of ignition part and an output driving part. Four cylinder screws with locking ring
hold crankcase halves together. It picks up the stator plate of the ignition system on the side
of ignition. Hirth reserves the right to make modifications to their designs without notice.
This manual covers basic engine operations and maintenance. For items and accessories not
made by Hirth, refer to appropriate manufacturer’s service instructions.
When performing maintenance, always use genuine Hirth parts.
Summary of Contents for F-23
Page 17: ...17 Note 1 inch 25 4 millimeters ...
Page 23: ...23 ...
