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Instructions Titan ZG 45PCI-HV
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forget the short piece of brass tube for the pump impulse. The rear screw on the cyl-
inder flange is difficult to reach, better use a hexagon headed screw for this. Secure
with Loctite. The copper bend can break due to vibration, to prevent this, fit a steel
supporting strap 10x1 mm between a carburettor and motor mount screw.
As written before, the straight ends of the copper water pipe bend must be cut off.
The complete length of the copper bend has too large an internal surface area. This
causes more droplets of petrol to form and cling to the inside due to the slow airspeed
through the bend, when the engine is throttled back. By opening the throttle these
droplets will be sucked into the engine, causing the engine to run extremely rich
momentarily, it is even possible, that the engine will not accelerate at all. If you then
decide to correct this problem by leaning out the low speed jet, you will notice that
you now have a problem when advancing the throttle again straight after throttling.
The engine will not accelerate into high speed, and will most probably stop, as not
enough time had elapsed for the build up of droplets in the bend. Now you see why a
too long a bend will not allow you to be able to adjust the two needle valves to cover
the whole throttle range satisfactorily.
We have discovered that it is an advantage to paint the inside surface of these
intake bends with two component car paint
. This leads to less fuel droplets forming
or more probable, these droplets do not adhere so strongly. This form of tuning, by
the way, works as well with our cast aluminium bends. If you have the patience, you
can make a bend from epoxy glass fibre, which would allow a rather longer bend, as
the epoxy has the same desirable effect on the droplets as the car paint.
Where the intake ram tube is not long enough to reach right through the firewall, it is
best to fit a tube of a minimum of 50 mm diameter to go over the bell-mouth of the
intake ram tube. This tube can be fairly long and can end in a silencer box. The gap
between the 50 mm tube and the ram tube should be sealed with a piece of plastic
sponge to make it almost airtight. The tube need not be round, it also can be a square
box from 3 mm thick balsa sheet glued together. This tube does not effect the en-
gine‘s performance, as it is in effect a reservoir of air and it's length will not detune
the intake resonance.
Something to be carefully avoided is any screw or other metal part that falls in the
fuselage. You can guarantee it will end up being sucked into the engine. To avoid this
you must make up an air filter, which can easily be done by cutting a square piece
10x10 centimetres from the filter mat that is supplied for kitchen air filters, and then
gluing it to a Balsa frame. This filter element should be at least 20 mm away from the
intake bell mouth.
A (plastic) tea sieve placed over the intake bell mouth and glued directly onto the
firewall works just as well and is easier to make.
Warmed air from the exhaust system must not be sucked in by the carburettor!
