YS DZ170 User manual
3 If the engine is running rough at idle or too rich, turn the regula-
tor adjustment counter-clockwise to lean out the low end.
4 If the engine speeds up at idle, the low speed mixture is too
lean. Turn the low speed regulator adjustment clockwise to
richen the mixture.
TAPPET ADJUSTMENT
Tappet clearance is preset at the factory. Adjustment, if you needed,
should be checked after the initial break-in. For maximum perfor-
mance, valves should be checked as normal maintenance.
1 Clearance adjustment should be done when the engine is cool.
2 The proper clearance should be set at not more than 0.002"
maximum. The adjustment is achieved by loosening the lock nut
(g.3)andturningtheadjustmentscrew.Theenginemustbe
at top dead center on the compression stroke before any adjust
ments are made. This engine runs best with the valves set at a
tight setting. If the valves are set too loose ,power will be affected.
CAM GEAR TIMING
If for some reason you have to disassemble your engine, please follow
these important steps on reassembling the cam gear.
1 Remove the carburetor and backplate assembly. Notice the im-
pression mark or dot opposite the rod journal on the crankshaft.
This mark is to point straight down or lined up with the outer
case seam line at the bottom.
2 Reinstall the cam with the dot facing you and pointing slightly
to the left. This will allow the cam to turn to the right when prop-
erly installed. The dot should be pointing straight up when cam
is fully installed. Reinstall cam cover and timing is now set.
FUEL PUMP
If you must disassemble the fuel pump to change the diaphragm or
to clean, take care that the valves and springs are replaced in exactly
the same manner in which they were removed. Do not disassemble
thepumpneedlessly. Usecare withltering yourfuel andkeeping
the entire fuel system in good working order. It will help to prevent
fuel pump problems.
FEATURES
The DZ170 was developed for serious aerobatics competition and
large IMAC style aircraft. It differs from previous YS Engines in that
it does not use a high pressure fuel system but rather a true fuel
pump.
*Crankcase supercharging system unique to YS 4 stroke egines
*Fuel injected
*Convenient fuel pump adjustment
*High horsepower output with long service life
GLOW PLUG
Select the most appropriate glow plug from those designed specifically
for 4 cycle engines. Glow plug selection greatly affects the maximum
engine 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 performance. These are available from YS Parts & Service
or your favorite dealer.
INSTALLATION
WE RECOMMEND THATTHIS ENGINE BE MOUNTED ON ASHOCK
ABSORBING SOFT MOUNT
1 Connect the engine to the tank as shown in g.1. The recomm-
ended fuel tank size is 18 to 24 oz. A standard clunk type fuel
tank may be used. If this type of tank is used, you must use the
special clunk supplied with the engine. Please note that with
this clunk,all of the fuel cannot be used from the tank.
As soon as any part of the clunk becomes exposed, the engine
will stop due to air entering the fuel pump.
2 Alwaysuseafuellter.WerecommendYSlter(YS1195).
With this filter, you must remove the cloth portion of the filter
andleaveboththemetallterscreensinplace.
START UP
1 Alwaysbreakthefuellinebetweenthefuellterandthetankfor
lling.Thiswillhelptopreventdirtfromenteringthefuelpump.
To prevent ooding the engine, clamp the fuel line with a hemos-
tat or clip where it enters the fuel pump.
2 Open the high speed needle 2 turns from the closed position.
The engine should run very rich with the recommended fuel and
glowplug.WerecommendYS20/20fuel(20%nitro/20%oil)
which is available from several manufacturers.
3 An electric starter is mandatory for starting this engine.
Attemptingtohandstartthisengineisdifcultanddangerous.
4 Close the throttle to the idle position and connect the glow driver.
The engine is now ready for starting.
DO NOT ATTEMPT TO START ENGINE AT FULL THROTTLE AS
THIS IS VERY DANGEROUS. ALWAYS USE EXTREME CAUTION
WHEN ENGINE IS RUNNING.
BREAK-IN
To maximize engine performance and increase durability, please follow
this break-in procedure.
1 Usethesamesize(orslightlysmaller)propellerthanyouintend
touseinying.
2 Useagoodqualityfuelcontaining15%to30%nitro,andoilconn-
tent of 20% to 24%. Synthetic oil only. If you use caster oil, no
more than 2% is recommended.
DO NOT USE FOUR CYCLE FUEL DUE TO LOW OIL CONTENT.
3 After the engine has started, slowly bring the throttle up to full.
Set high speed needle so it is running at a good rich setting with
out the glow driver.
4 After the initial 20 minute break-in, mount the engine in the air-
craft and set the high speed to a richer than normal setting for the
rst10ights.Thiswillhelptolubricateallmovingparts.
HIGH SPEED NEEDLE ADJUSTMENT
1Adjustment of the high speed is done by the carburetor needle
valve.When the needle valve is turned clockwise, the mixture is
leaner. When it is turned counter-clockwise, the mixture is richer.
A good starting position for the high speed needle valve is 2 turns
open from the fully closed position. At this setting the engine will
be very rich and may die when you remove the glow driver.
If this happens, turn the needle valve in 1/2 turn and try again.
The nal running setting for the high speed needle will be approx-
imately 1 to 1-1/2 turns open from fully closed.
2 Whentheengineisstarted,openthethrottlegradually.Next,nd
thepeakposition(highestRPM)byadjustingtheneedlevalve.
Then the needle valve should be opened approximately 1/8 _ 1/4
turns from full RPM to achieve best performance.
REGULATOR ADJUSTING
DO NOT ATTEMPT TO ADJUST THE REGULATOR SCREW WITH
THE ENGINE RUNNING. STOP THE ENGINE BEFORE ADJUST-
ING THIS SCREW
The low speed adjustment is the regulator screw on the front of the
engine. Turning the screw clockwise will richen the idle mixture, and
counter-clockwise will lean the idle mixture. It is preset at the factory
but may require further adjustment depending on fuel and conditions
in your areas.
1 Wait until the engine is up to operating temperature before adjust
ing the idle mixture.
2 Closethethrottlegraduallytoanidle(approximately2,200rpm).
Letitidlefor15-20secondsandthenslowlyadvancethehrottle.
The adjustment is correct when low to high speed has a smooth
transition.
OPERATOR’S MANUAL
DZ170
(Parts No.YS0089)
SPECIFICATIONS
Bore 34mm
Stroke 30.8mm
Displacement 27.95cc
Weight 955g
Practical rpm 2,000 -10,000rpm
g.1
g.2
g.3
Fuel Filter
6 25
58
134
114
Regulator
Fuel Tank Clunk
High Speed Needle Valve
PROPELLER INSTALLATION
Due to the high output power of the DZ170 engine, it is supplied with
a double locknut system for added safety. If you use any other type of
spinner or prop nut device, make sure it is of the double nut type.
1 Mount the propeller and tighten the rear nut. Next, tighten the
frontnutasshowning.2.Therearnuthasanoffsetshoulder
so the front nut will secure itself to the rear nut.
2 Select a good quality propeller that will allow the engine to run
at maximum speed between 7,800 to 8,800 rpm range.
We recommend sizes 17X13 to 18X11. Other prop sizes may
be used as long as the correct rpm range.
TappetClearance
# Part# Description QTY
1 YS5900 Crankcase 1
2 YS4495 Valvecover 1
3 YS0510 Headcovergasket 1
4 YS0515 Valvecoverscrewset 2
5 YS5905 Headgasket 1
YS5910 Headassembly
6 YS4505 Cylinderhead 1
7 YS2160 Intake valve 1
8 YS2165 Exhaustvalve 1
9 YS5915 Exhaustvalvespring 1
10 YS5920 Intakevalvespring 1
11 YS2175 Springretainerset 2
12 YS2180 Valve spring retainer clips 4
13 YS0555 Rockerarmset 2
14 YS4510 Intaketappetadjustingscrew 1
15 YS4515 ExhausttappetAdjustingscrew 1
16 YS0565 Tappetadjustinglocknuts 2
17 YS0570 Rockerarmshaft 1
18 YS0575 Rockerarmshaftscrew 1
19 YS0580 Eringset 2
20 YS2615 Headboltset 5
21 YS5925 Crankshaft 1
22 YS2190 Crankshaftring 1
23 YS5930 Cylinderliner 1
24 YS5935 Piston 1
25 YS5940 Wristpin 1
26 YS5125 Pistonring 1
27 YS5945 Connectingrod 1
YS5980 Backplateassy.
28 Back plate 1
29 Discvalve 1
30 Disc valve pin 1
31 Disc valve screw 1
32 YS0645 Backplategasket 1
33 YS4550 Carburetorinsulator 1
34 YS4705 Iusulatorgasket 1
35 YS4560 Backplatescrewset 6
36 YS0655 Camgearcover 1
37 YS0660 Cam gear cover O-ring 1
38 YS0665 Camgearcoverscrewsset 2
39 YS4565 Cam 1
40 YS5985 Camfollowers 2
41 YS4580 Exhaustpushrod 1
42 YS4585 Pushrodcover 1
43 YS0690 PushrodcoverO-ring 4
44 YS1050 Frontbearing 1
45 YS1730 Frontbearingoilseal 1
46 YS0701 Rear bearing 1
47 YS0705 Camgearbearingset 2
YS5950 Pumpassembly
48 Regulator body 1
49 YS0195 Regulatoradjustingscrew 1
50 YS0725 RegulatoradjustingscrewO-ring 1
51 YS4605 Diaphragm 1
52 YS4610 Regulatorspring 1
53 YS4615 Regulatorscrewset 2
54 Fuelpumpbody 1
55 YS4625 Pumpvalve 2
56 YS5990 Pumpvalvespring 2
57 Pumpplate 1
58 YS4640 Pumpscrews 2
59 YS4645 Pumpgasket 1
60 Plunger 1
61 YS4655 Pumpinsulator 1
DZ170 Parts list
62 YS4660 Insulator O ring 1
63 YS4665 Pumpbracket 1
64 YS4735 Upperpushrod 1
65 YS4740 Lowerpushrod 1
YS4745 Carburetorassembly
66 YS4750 Carburetorbodywiththrottlebarrel 1
67 Throttle barrel 1
YS2740 Needle valve assembly
68 YS2690 Highspeedneedlevalve 1
69 YS2695 HighspeedneedlevalveO-ring 1
70 YS2700 High speed needle seat 1
71 YS2705 NeedlevalvesocketO-ringset 2
72 YS2710 Needle valve detent 1
73 YS4755 Throttlebarrelseal 1
74 YS1090 Throttlebarrelretainer 1
75 YS0785 Throttlestopscrew 1
76 YS0790 Throttlestopspring 1
77 YS0200 Throttle arm set 1
78 YS4760 Carburetor gasket 1
79 YS2715 Drivewasher 1
80 YS2720 Drive washer retainer 1
81 YS6000 Intake pipe 1
82 YS0840 Intake pipe O-ring 4
83 YS1540 Wristpinaccessplug 1
84 YS0825 Propellerwasher 1
85 YS6145 Propellernutset HEX13mm 2
86 YS4723 Wrist pin access screw 1
87 YS5130 Checkvalve 1
YS4710 Gasket set 4
YS4715 Oringset 14
YS4720 Fuel tank clunk 1
YS5970 Tubeholder 1
YS Parts and Service
1370 PORTER DRIVE MINDEN NEVADA 89423
Phone: 775-267-9252 Fax: 775-267-9690
56
56
52
69
76
82
35
82
43
43
B
C
D
A
4
2
3
1
5
71
74
85
86
64
63
54
60
65
61
62
59
55
55
57
51
58
48
50
49 D E TA IL D
53
70
72
68
78
66
75
73
67
77
DETAIL C
DETAIL B
28
32
29
30
81
35
34
21
33
46
83
47
39
47
37
36
38
45
44
80
79
84
40
43
40
41
42
27
25
24
23
26
19
13
14
16
20
18
15
13
17
19
16
22
DETAIL A
11
9
6
8
11
10
12
12
7
87
31
Other YS Engine manuals
Popular Engine manuals by other brands
Mile HaoXianG Model Technology
Mile HaoXianG Model Technology DLE30 user manual
SELVA MARINE
SELVA MARINE Antibes Series owner's manual
Kohler
Kohler LOMBARDINI MARINE LMG 4000 owner's manual
BRP
BRP RORAX V-810 Shop Manual
FAAC
FAAC T-MODE TM R Series manual
SEW-Eurodrive
SEW-Eurodrive R...7 Series operating instructions
