Description Of The Engine, Its Systems, And; Model 2706 - Gobler-Hirthmotoren KG 2706 Service Manual

Chapter 1
Description of the Engine, Its Systems, and Essential Technical Data
1.1 Overview

1.1.1 Model 2706

The Hirth 2706 engine (Illus. 1.1.1-1), from Göbler-Hirth Engines Ltd., is a fan-cooled, side-
regulated, two cylinder inline, two stroke engine.
The cylinders consist of an aluminum alloy coated with an abrasion-resistant surface. The
cylinders are attached to the crankcase with bolts, washers and hexagonal nuts. The cylinder
heads consist of a special non-melting aluminum alloy, which resists high temperature with
an even hardness. They are fastened to the cylinder without any sealant, using cylinder bolts
and washers .
The pistons consist of an aluminum alloy and are packed with two piston rings against the
cylinder surface. The piston is connected to a piston rod with a gudgeon pin and needle roller
bearing.
The crankshaft is made of Chromoly steel (42CrMo4) and is positioned in five grooved ball
bearings. It is a constructed crankshaft in which the individual parts are pressed together to
form the complete crankshaft. Two grooved ball bearings are attached on the power take off
side, two more between the crank control handle, and one on the ignition side. The power
take off is cone-shaped and has a centric coil in order to wind a connecting cone onto the
power take off side. The piston rods are connected to the crankshaft with crank pins and
needle roller bearings.
The crankcase consists of an aluminum alloy. It is constructed as an axial divided case and
consists of a lower and an upper part. It is held together by three cylinder bolts with safety
washers, and in addition by the eight fastening bolts of the cylinders. On the ignition side, it
includes the statorplate of the ignition and is consctructed so the the fan housing can be
mounted over it.
Illustration 1.1.1-1 (Engine 2706)
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