DZ70 OPERATOR'S MANUAL

Cleaning
Brake-in
This engine is using silicon gaskets, “O” rings etc. Please use methanol or
1. Starting the engine with high speed needle valve 2 turns open from the
SPECIFICATIONS model engine fuel for cleaning. Do not use Kerosene, Gasoline, Machine
FIG 1 fully closed position and idle position on carburetor.
oil, Automobile parts cleaner or house hold lubricants to clean. It will harm
Bore 27.7mm 2. After start the engine, increases rpm gradually by operates throttle control
silicon parts.
Stroke 19.0mm up and down. Do not suddenly open throttle to fully open position.
Weight (engine) 486g 3. If mixture is too rich and miss firing, turn clockwise high speed needle
valve to leaner mixture.
Engine Cooling

Crankcase
(muffler) 33g
4. Brake-in the engine one or two tanks of fuel on the ground with richest Be sure to secure cooling air for engine cooling. If it is not enough cool-
54
45

35
Practical RPM 2,000-15,000rpm ing air for the engine causes heat up the regulator and carburetor to make
possible mixture setting.
vaporized or percolates the fuel and will get deteriorations of engine perfor-
mance or stop the engine. Please read carefully below for provision.
Idling adjustment
1. Please open air intakes and outlets as big as possible.
1. To get 2,000rpm to 3,000rpm idling.
48 20 2. Take off cowling when you make long engine adjustment included idle
2. When the regulator is turned counter-clockwise, the idle mixture is leaner.
adjustment. When air temperature is high, it may heat ups the regulator
High speed needle When the regulator is turned clockwise, the idle mixture is richer. Adjust
and carburetor to make vaporized or percolate the fuel even with out cowl
regulator by turn 45 degree at a time.
ing. If it happens, wait till engine well cooling down before you restart and
3. If idle mixture is too rich, gradually rpm drops and stops after continuous
adjust.
idling. If engine stops when you change attitude of airplane on the ground
Fuel Filter also too rich on idle mixture. If mixture is too lean on idle, rpm is go up
Rusting provision
Regulator Tube A and down and not keep stable when you make continuous idle.
Do not leave fuel in the engine after you finished for day. If you store the en-
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gine long period of time, few drops (about 1cc) of model engine lubricant oil
Glow Plug
from carburetor and clank several times. Do not use Automobile engine oil.
Select the most appropriate glow plug from those designed specifically for
They will not mix together with alcohol.
4 cycle engines. Glow plug selection greatly affects the maximum engine
Tube B
output and low idle. If RPM’s decrease or stop when the booster cord is
removed, replace the plug. We recommend the YS#4 plug for maximum
Parts and Repair Service
Front Nut Fuel tank clunk If you can not find repair parts form hobby shops, you can order parts direct
performance.
Rear Nut to our factory. We also do repair your engine at our factory. If you need
98
repair service, please make detailed of states and send together with the
Tappets Adjustment
engine.
Safety Instructions Fuel 1. Tappet clearance is preset at the factory.
In order for you to use of the engine, please read through this instruction 1. Use a good quality alcohol based model engine fuel containing 10% to 2. Clearance adjustment may need after first one hour running time due to
manual carefully. This instruction manual uses special words, if you have 30% nitro, and oil content 5% to 25%. You can not use gasoline fuel. initial wear. After first adjustment, clearance should be checked as normal Warranty
any difficulties for understanding, please ask the hobby shop you purchased 2. When you filling the tank, disconnects Fuel Tube “A”, or Fuel Tube “B” maintenance for every 10 hours running for maintain maximum perfor We strictly inspect each process of production from parts to final assemble
or contact us directory. see “Fig.1” from connecting tube to filling. If you use “T” nipple on the fuel mance. for keep good quality. If a performance deteriorates or part fails due to a
1. Mount the propeller must use propeller nut supply with the engine. line to filling, use fuel stopper on the Fuel Tube “A” see “Fig.1” to avoid fuel 3. Clearance adjustment should be done when the engine is cool. manufacturing error under normal usage will repair no charge with in 1 year
2. Select a good quality propeller and follow instruction by manufactures. in to the engine. 4. The proper clearance should be set at 0mm (0.000”) to 0.1mm (0.004”). starting from the date of purchase. Warranty will not cover normal wear.
3. Select a propeller size not increases practical rpm in the air. The adjustment is achieved by loosening the lock nut see “Fig.2” and Even with in 1 year warranty term, improper disassemble or assemble, un-
4. Be sure not people standing front and sides of propeller while running. Propeller turning the adjustment screw see “Fig.2”. The engine must be at top der improper usage, any modification will avoid this warranty and there will
5. Use electric starter to start the engine with idle position of the carburetor. 1. Due to the high output power of the DZ70 engine, it is supplied with dead center on the compression stroke before any adjustments are made. be normal charge for parts and labors.
6. After start the engine, move behind of propeller and well adjust needle a double locknut system for added safety. Mount the propeller and tighten This engine runs best with the valves set at a tight setting. If the valves
setting before you fly. the rear nut. Next, tighten the front nut. The rear nut has an offset shoul are set too loose, power will be affected.
7. It becomes extreme high temperature while and after engine runs. Do der so the front nut will secure itself to the rear nut.
not touch engine, exhaust header, muffler, and any parts attached to the 2. Please retighten propeller nut periodically. Fig2
engine while engine runs or before cool it down. 3. Select a propeller that will allow the engine to run at maximum speed be
8. If engine runs not correctly, DON’T FLY! tween 8,000 to 10,000 rpm range. 0 - 0.1mm
9. Do not use this engine other than radio controlled airplanes. Can not 4. We recommend sizes 14x7,14x8,15x7. Other prop sizes may be
use for radio controlled helicopters. used as long as the correct rpm range.
10. You have full responsibility while you operate the engine. Please be ex
tra care for safety when never you operate the engine. High Speed Needle Adjustment
1 Adjustment of the high speed is done by the carburetor needle
valve.When the needle valve is turned clockwise, the mixture is
Installation leaner. When it is turned counter-clockwise, the mixture is richer.
WE RECOMMEND THAT THIS ENGINE BE MOUNTED ON A SHOCK ABSORB- A good starting position for the high speed needle valve is 2 turns Cam Gear Timing
ING SOFT MOUNT open from the fully closed position. At this setting the engine will
If for some reason you have to disassemble your engine, please follow
be very rich and may die when you remove the glow driver.
1 Connect the engine to the tank as shown in fig.1. The recommended fuel these important steps on reassembling the cam gear.
If this happens, turn the needle valve in 1/2 turn and try again.
tank size is 400 to 500cc. A standard clunk type fuel tank may be used. If 1. Remove the carburetor and back plate assembly. Notice the impression
The final running setting for the high speed needle will be approx-
this type of tank is used, you must use the special clunk supplied with the mark or dot opposite the rod journal on the crankshaft.
imately 1 to 1-2 turns open from fully closed.
engine. Please note that with this clunk,all of the fuel cannot be used from 2. This mark is to point straight down or lined up with the outer case seam
2 When the engine is started, open the throttle gradually. Next, find
the tank. As soon as any part of the clunk becomes exposed, the engine will line at the bottom and hold crankshaft securely.
the peak position ( highest RPM ) by adjusting the needle valve.
stop due to air entering the fuel pump.
Then the needle valve should be opened approximately 1/8 _ 1/4 3. Reinstall the cam with the dot facing you. After you fully installing cam
2 Always use a fuel filter. We recommend YS filter ( 6720 ).
turns from full RPM to achieve best performance. and then check dot should be pointing straight down will give you right
With this filter, you must remove the cloth portion of the filter and leave
timing.
both the metal filter screens in place.
NO. ITEM NO. DESCRIPTION QTY
1 G7001 Crank case 1 12
G7002S Cylinder head assembly
2 G7002 Cylinder head with liner 1
3 F5103 Intake valve 1
4 F5104 Exhaust valve 1
5 F5105 Valve spring set 2
82 10
6 F9106 Spring retainer set 2
7 F9107 Valve spring clips 4
8 F3108 Cylinder head gasket 1
9 G7009 Head bolt set 4
10 F5111 Valve cover 1 11
11 F5112 Valve cover gasket 1
12 F5113 Valve cover screws 2 7 81 13
13 F5114 Intake pipe 1
14 F5115 Intake O rings 2
14
15 G7015 Crankshaft 1 6
16 G1016 Crankshaft ring 1
33 9
17 G1017 Rear bearing 1
18 F5118 Front bearing 1
5
19 F5119 Front bearing seal 1 14
20 F5120 Drive washer 1 34 2
21 F5121 Drive washer retainer 1 31
22 F1266 Prop washer 1
23 F2267 Prop nut set 2 84
24 G7024 Piston 1 28 55
25 G1025 Piston ring 1 30 63
26 F6126 Wrist pin 1
31 28 54 56
27 G1027 Wrist pin retainers 2 83
28 F5128 Rocker arm set 2
29 F2013 Intake tappet adjusting screw 1 34
30 F2014 Exhaust tappet adjusting screw 1
31 F1214 Adjuster nut set 2 84 48
32 F5131 Rocker arm shaft 1 9 63
33 F5132 Rocker arm screw 1 32
34 F1217 E ring clip set 2 29
35 G7034 Cam 1 43 3 51
36 F5135 Cam cover 1 62
37 F5136 Cam cover O-ring 1
4
38 F5137 Cam gear cover screws 2
25 52
39 F5138 Cam bearing set 2 41
40 F1236 Cam follower set 2
41 G7040 Push rod 1 26
42 G7041 Push rod cover 1
26 51 53
43 F5142 Push rod cover O ring 4
44 G1043 Con rod 1
26 50
45
G1044A
G1044
Back plate assembly
Back plate 1 A 60
46 G1045 Disc valve 1
47 G1046 Disc valve pin 1 42 24 45
48 G1047 Disc valve set screw 1 59
49 F5149 Back plate gasket 1 46 61
50 F5150 Back plate screws 2
43 79 58
G7050S Carburetor assembly 1 49 78
51 G7050 Carburetor body with throttle 1
8 44 57
G7087 Throttle barrel 1 40 47
52 G7051 Throttole barrel seal 1
53 R6124 Throttle barrel retainer 1 16
54 F1260S Throttle arm set 1
55 F1258 Throttle stop screw 1
75
56 F1259 Throttle stop spring 1
38 71
36 70
F5158S Needle valve set 15 72
57 F5158 Needle valve 1
58 F1546 Needle O ring 1
37
59 F1555 Needle socket 1
39
60 F1556 Needle socket O ring 2 35 74 77
61 F1557 Needle detent 1
62 F5164 Carburetor gasket 1 39 17
64 72
63 F5165 Carburetor screws 4
70
G7163S Fuel pump assembly 71
19 69
64 G7163 Regulator body 1
65 F1245 Regulator adjusting screw 1
1
66 F 1246 Regulator adjusting screw O-ring 1
73
67 G7166 Diaphram 1 80
68 F2051 Regulator spring 1
67
69 G7068 Regulator screw set 2
70
71
G7069
G7070
Fuel pump body with plunger
Pump valves
1
2 18
68 DETAIL A 76
72 G7071 Pump valve springs 2 66
G7072
21
73 Pump plate 1
65
G7073
74 Pump screws 2
20
75 G7074 Pump gasket 1
76 G7075 Pump insulator 1 22
77 F 2188 Insulator O ring 1
78 F 2059 Pump bracket 1
23
79 G7078 Upper push rod 1
80 G7079 Lower push rod 1
81 F 4088 Check valve

82
F5173S
F5173A
Muffler set
Muffler assembly 1
YAMADA MFG. CO.,LTD.
83
84
F5174
F5175
Exhaust pipe
Rock nuts
1
2
67 TUCHITORI, INUYAMA, AICHI, JAPAN 484-0917
F2083 Fuel tank clunk 1 2013 12 TEL (0568) 67-0265/ FAX (0568) 67-7801
G1080 Gasket set 3
G7086 O ring set 13 http://www.yspower.co.jp/