13
Breaking-in the engine
The engine is factory tested and pre adjusted. While breaking-in the engine the level
of wear is increased. While breaking-in use a mixture of 1:25.
We recommend for the rst 30 Minutes a maximum of 3000 RPM. Afterwards you can
increase up to 5.000 RPM for a few seconds. Change continuously the throttle setting
and keep an eye on the engine temperature the rst two hours. Change the mixture to
1:30 and load the engine normally. Usually the breaking-in procedure lasts three hours.
Maintenance
The construction of the engine is laid out for a minimum of maintenance eort. The
valve gap has only to be controlled after all two or three operating hours after break-
ing in.
Lubricate the rocker arm bearings and the valve shafts while you are at it.
While breaking in, the valve gap has to be checked at shorter intervals, check it after 10
minutes the rst time, than go on for about 20 minutes and check it again, after that,
check the valve gap every 30 minutes, until after about ve hours only minor changes
will occur. Afterwards it is enough to check it every four or ve hours.
The backside of the crankcase is connected to the carburetor with a tube. This tube
guides the alternating crankcase pressure to the diaphragm pump into the carbure-
tor to actuate it. If you deploy the engine for aerobatics, with long vertical climbs and
hover maneuver like me, then have a regular look (at least while breaking-in) on this
tube. Oil in this line damps the alternating pressure and reduces the pump capacity.
As a result the engine runs too lean and can stop. Do not worry too much about it,
this is just meant as a hint to be prepared!
The following points have to be kept in mind as well, to guarantee a long faultless life:
Condition of the ignition battery.
Contact gap of the spark plugs, it should be 0.4 mm.
Change the spark plugs, if the electrodes are burned away.
Hint: It is a good idea to change the sparkplugs (NGK CM-6) after breaking-in the engine.
The higher metal abrasion during breaking-in is likely to collect on the insulator of the
sparkplug, it will then short the HT to earth.
Clean your engine occasionally with „WD 40“, especially the valve train needs this.
Afterward lubricate it as described in the section “Lubrication” with chain lube or our
Würth „HHS 5000“.
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General