Solo 2625 01i neo User manual

solo
service
Service-manual
For the aircraft engines
2625 01i neo and 2625 02i neo
SOLO
Kleinmotoren GmbH
Stuttgarter Str. 41
D - 71069 Sindelfingen
Tel.: [phone]
Fax.: [phone]
Edition 1 dated 26.11.2020

2625 01i neo
2625 02i neo
Service Manual
SOLO
KLEINMOTOREN
GMBH
Edition 1 dated 26.11.2020 page 2
Table of contents
1General hints and description of the engines ............................................................ 3
2Description..........................................................Fehler! Textmarke nicht definiert.
2.1 Basics...........................................................Fehler! Textmarke nicht definiert.
2.2 Engine electrics overview................................................................................... 4
2.2.1 Working method of the engine control unit (ECU)........................................5
2.2.2 Wire diagrams electrics ...............................................................................6
2.3 Fuel supply system.......................................Fehler! Textmarke nicht definiert.
2.3.1 Fuel line diagram...................................Fehler! Textmarke nicht definiert.
2.4 Redundancy functions..................................Fehler! Textmarke nicht definiert.
3Inspections and maintenance intervals ...............Fehler! Textmarke nicht definiert.
4Disassembly, check and assembly......................Fehler! Textmarke nicht definiert.
4.1 Necessary tools, oil, adhesives and sealantsFehler! Textmarke nicht definiert.
4.2 Tolerances for tightening torques.................Fehler! Textmarke nicht definiert.
4.3 Engine..........................................................Fehler! Textmarke nicht definiert.
4.3.1 Disassembly of the engine......................................................................... 13
4.3.2 Check of the individual parts..................Fehler! Textmarke nicht definiert.
4.3.3 Assembly of the engine .........................Fehler! Textmarke nicht definiert.
4.4 Throttle valve system 23 00 891 V1/V2............................................................17
4.4.1 Hints for disassembly.............................Fehler! Textmarke nicht definiert.
4.4.2 Check of the individual parts..................Fehler! Textmarke nicht definiert.
4.4.3 Hints for assembly.................................Fehler! Textmarke nicht definiert.
4.5 RPM sensor..................................................Fehler! Textmarke nicht definiert.
4.5.1 Hints for assembly.................................Fehler! Textmarke nicht definiert.
4.6 Fuel supply unit............................................Fehler! Textmarke nicht definiert.
4.6.1 Hints for disassembly................................................................................. 19
4.6.2 Check of the individual parts..................Fehler! Textmarke nicht definiert.
4.6.3 Hints for assembly.................................Fehler! Textmarke nicht definiert.
5Diagnosis and elimination of engine malfunctionsFehler! Textmarke nicht definiert.
5.1 Basics...........................................................Fehler! Textmarke nicht definiert.
5.1.1 Handling with WinTrijekt NEO.................................................................... 20
5.1.2 One important rule of thumb ….................................................................. 20
5.2 Error memory of the engine control unit .......Fehler! Textmarke nicht definiert.
5.3 Check the status of the engine.....................Fehler! Textmarke nicht definiert.
5.4 Special cases...............................................Fehler! Textmarke nicht definiert.
5.4.1 Engine will not start ...............................Fehler! Textmarke nicht definiert.
5.4.2 Engine gets hot......................................Fehler! Textmarke nicht definiert.
5.4.3 Engine does not achieve full power or power drops.........Fehler! Textmarke
nicht definiert.
5.4.4 The generator control lamp lights up while the engine is running ...... Fehler!
Textmarke nicht definiert.

2625 01i neo
2625 02i neo
Service Manual
SOLO
KLEINMOTOREN
GMBH
Edition 1 dated 26.11.2020 page 3
6Notes...................................................................Fehler! Textmarke nicht definiert.
1 General hints and description of the engines
This service-manual shall give the engine specialist necessary hints for repairs and
maintenance of the engine and help him solving specific problems and familiarize him
with engine-specific special features. This service-manual is valid together with the
engine-manual and the spare-parts-list. General knowledge of two-stroke-engines is
required to work on SOLO-aircraft-engines.
! Attention !
Because this engine is used as a certified engine for motor gliders, the national
authorizations of the specific certifying staff must be maintained.

2625 01i neo
2625 02i neo
Service Manual
SOLO
KLEINMOTOREN
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Edition 1 dated 26.11.2020 page 4
2 Description
2.1 Basics
The aircraft engines SOLO 2625 01i neo and 02i neo are water cooled two cylinder two-
stroke engines with piston-ports and map-controlled intake-manifold fuel injection and
ignition. They are lubricated by a fuel-oil-mixture. They are based on the 2625 01i or
2625 02i.
2.2 Engine electrics overview
Note: Redundant components are underlined in the following overview.
−Sensors:
oInductive RPM-sensor and crankshaft position sensor on the rotor of the
generator (redundant sensor unit)
oAngle sensor of throttle valve(redundant sensor unit)
oEngine temperature sensor
oAmbient air temperature sensor
o2 fuel pump current sensors (included in the fuel pump electronic unit)
oAmbient pressure sensor (included in Trijekt bee)
−Actuator:
o4 injection valves (two per throttle body, of which one belongs to channel A and
one to channel B)
o2 fuel pumps(included in the fuel supply unit) with fuel pump relays (included in
the fuel pump electronic unit)
o2 double ignition coils, of which one ignition line leads to the first and the second
cylinder head. 2 ignition drivers (integrated in the ECU).
oEngine control unit (ECU) Trijekt bee in redundant design (ignition- and injection
control unit)
−Power supply:
oGenerator
oController SOLO GR 30
oCapacitor, generator-LED, resistance
obattery
−Other:
oWiring
oPlug connector
oSwitches, relays
oFuses

2625 01i neo
2625 02i neo
Service Manual
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Edition 1 dated 26.11.2020 page 5
2.2.1 Working method of the engine control unit (ECU)
The engine control unit continuously records the measured values by the sensors. With
the obtained data and the stored maps, the injection quantity and ignition timing are
always adjusted during engine operation, so that the engine works optimally. The ECU
corrects the injection quantity depending on the current density level. When the engine
reaches its maximum permissible speed, it is limited to prevent damage due to
overspeeding.
In addition, the engine control system enables the engine to be started quickly and
without any problems. This is achieved by firstly activating the fuel pumps for about 3
seconds after switching on the engine to build up fuel pressure and secondly by initially
enriching the mixture a little when the engine is cold. The later makes a choke or any
other cold start devices superfluous. The engine is always started in idle position.
To facilitate fault diagnosis, the ECU has an integrated fault memory. It contains all faults
detected by the engine management system as well as information on whether limit
values (e.g. for engine speed or cooling water temperature) were exceeded during
operation.
The engine control unit has two digital communication interfaces: RS 232 (serial
interface) and CAN. The former allows a computer to be connected to check the status of
the engine control unit or read the error memory using the WinTrijekt NEO software,
which can be downloaded from the SOLO website https://aircraft.solo.global/de/. Both
engine operation data and fault messages can be transmitted via the CAN interface, for
example to display them on an engine operation unit. A CAN protocol is available from
SOLO on request.

2625 01i neo
2625 02i neo
Service Manual
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Edition 1 dated 26.11.2020 page 6
2.2.2 Wire diagrams electrics
Wire diagram control unit
-
+
-
+
-
+
-
+
Stromversorgungsstecker
(Deutsch DTM06-4S)
Hauptstecker
(TE 929504-4)
Benzinpumpen-Elektronikeinheit
1
4
Zylinder 2
(vorne)
Kanal B
6
20
21
23
24
5
22
7
Signalstecker
(Deutsch DTM06-6S)
5A M
Sicherung FP 2
5A M
Drehzahlsensor
(Deutsch DTM04-6P
Stecker)
Sicherung IC 2
5A M
Sicherung IC 1
5A M
1
2
6
2
10
8
Hauptstecker
(TE 929504-4)
Benzinpumpen-Elektronikeinheit
1
2
3
4
3
5
7
9
Sicherung 1 ECU
4A M
solo
Vertriebs- und
Entwicklungs- GmbH
10
Wassertemp.
16
Signalmasse 1
25
Benzinpumpe P1
17
Leistungsmasse
26
Signalmasse 2
34
Zündspule 2
8
Signal DKS 1
14
RS 232 RXD
31
CAN H
9
Sicherung FP 1
Drehzahl Kanal 2
Stromsignal P1
15
RS 232 TXD
23
EV Zyl. 2, Kanal B
32
+5V
3
+ 12V
13
Stromsignal P2
21
EV Zyl. 2, Kanal A
30
CAN L
4
Benzinpumpe P2
29
Drehzahl Kanal 1
22
EV Zyl. 1, Kanal B
Verteilerleiste +12V
28
29
15
6
RXD
3
3
TXD
3
4
+
-
ZS 1
ZS 2
-
+
18
19
Sicherung 2 ECU
4A M
CAN
L
H
1
2
3
4
5
1
2
3
4
5
6
16
Winkelsensor
Drosselklappe
(Deutsch DTM04-6P
Stecker)
6
1
2
25
26
8
9
10
27
4
Sensor Wasser-
temperatur
(Bosch 1 928 403 874
Stecker)
30
5
17
Gesamtschaltplan Steuerung
2625 01i neo und 2625 02i neo
ECU
ECU(Trijekt bee) - Pinbelegung
1
Leistungsmasse
11
Verteilerleiste Leistungsmasse
EV
Zylinder 2
(vorne)
Kanal A
Zylinder 1
(hinten)
Kanal A
EV
34
31
32
33
11
12
13
14
EV
EV
1,5 mm2/ 16 AWG (1,5 mm2nicht für ECU-Stecker geeignet)
0,5 mm2/ 20 AWG
1,0 mm2/ 17 AWG / 18 AWG
0,35 mm2/ 22 AWG
Sensor
Umgebungsluft-
temperatur
Anmerkungen: • Alle Knotenpunkte müssen ausreichend vor Vibration geschützt sein. • Falls anstelle der Solo Benzinversorgungseinheit andere Pumpen zum Einsatz kommen, müssen ggf. die Sicherungen FP1 und FP2, sowie die Kabelquerschnitte der Versorgungsleitungen, angepasst werden. (Sicherungen max. 7,5A mt) • Solo empfiehlt für die Motorumgebung die Verwendung feinstdrähtiger, temperaturbeständiger Litze. (z.B. SiFF) • Die Benzinpumpen-Elektronikeinheit ist sowohl mit einem PCB - Hauptstecker als auch mit zwei separaten, kabelgebundenen Steckern (Signal und Stromversorgungsstecker) erhältlich.
04.01.2020
Schalter Zündkreis 2
Schalter Zündkreis 1
5
2
Leistungsmasse
12
Signal DKS 2
20
EV Zyl. 1, Kanal A
27
+ 12V
Lufttemp.
18
Zündspule 1
28
2
RS 232
empfohlene Kabelquerschnitte: (gemäß DIN VDE 0295: unterstrichen, US-Norm: kursiv)
Zylinder 1
(hinten)
Kanal B

2625 01i neo
2625 02i neo
Service Manual
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Edition 1 dated 26.11.2020 page 7
Wire diagram power supply Wire diagram fuel pump
electronic unit
a) with signal and power supply
connector
b) with main connector
Benzinpumpen-
Elektronikeinheit
-
+
Pumpe 1
+
-
Pumpe 2
1
2
3
4
Strom-
versorgungs-
stecker
(Deutsch
DTM04-4P)
6
Signalstecker
(Deutsch DTM04-6P)
1
2
3
4
5
3
4
empfohlene Kabelquerschnitte: (gemäß DIN VDE 0295: unterstrichen, US-Norm: kursiv)
0,5 mm2/ 20 AWG
2,5 mm2/ 14 AWG
4 mm2/ 10 AWG /11 AWG
Ladekontrolllampe
1
1
1
2
DTP
06-2S
DTP
04-2P
0,2A M
DEUTSCH-Stecker
DEUTSCH-Stecker
1
2
DTM
04-4P
DTM
06-4S
2
3
Batterie
Spannung: 12V bzw. 13,2V
6-zelliger Blei- oder
4-zelliger LiFePo4-Akku
WICHTIG!
max. zul. Ladestrom ≥ 30A
+
ELKO 47mF, 40V
EPCOS B41458B7479M000
-
Verteilerleiste +12V
Motorsystem
Verteilerleiste Leistungs-
masse Motorsystem
+
-
80A T
40A M
Generatorsicherung
Gesamtschaltplan Versorgung
2625 01i neo und 2625 02i neo
solo
Vertriebs- und
Entwicklungs- GmbH
Batteriesicherung
470 Ω, 1W
Anlasser
Hauptschalter
Phase 2
Phase 3
+ Supply
GEN
OVP
REGLER
GR30
GND
Charge Out
15.11.2019
6 mm2/ 9 AWG / 10 AWG
10 mm2/ 6 AWG / 7 AWG
DELPHI Metri-Pack 480 Stecker
4
Phase 1
1
1534 4628
1213 1592
1
2
2
3
3
Engine turn
Anmerkungen: • Der Regler sollte nicht direkt am Motor bzw. am Klapptriebwerk montiert werden.
2
GENERATOR
Ducati, 3-Phasig,
permanent-
magneterregt,
500W

2625 01i neo
2625 02i neo
Service Manual
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Edition 1 dated 26.11.2020 page 8
2.3 Fuel supply system
The fuel supply system basically consists of a tank, pipes, a throttle valve system, fuel
cock, fuel pumps with check valves, fuel filters and the pressure regulator.
The SOLO fuel supply unit contains fuel pumps, check valves, pressure regulator and
fine filter.
2.3.1 Fuel line diagram
The following fuel line diagram shows the fuel system when using the SOLO fuel supply
unit (BVE), but without the required tank inlet filter(s). If other fuel pumps are installed,
deviations may occur. These are then at the discretion and responsibility of the aircraft
manufacturer.
shut-off valve
pump 1
pump 2
fuel tank
(main tank)
pressure
regulator
included in fuel-supply-unit
fine mesh
filter
included in throttle-body-unit
IV
IV
IV
Cyl. 1 (rear)
Channel A
Cyl. 1 (rear)
Channel B
Cyl. 2 (front)
Channel A
Cyl. 2 (front)
Channel B
IV

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2625 02i neo
Service Manual
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2.4 Redundancy functions
In order to ensure a high degree of operational safety, almost all electrical components
essential for engine operation are redundant (see 2.3). The exception is the ECU itself,
where redundant electronics have been omitted due to its high reliability. However, all
critical pins on the ECU connector are still duplicated. (= “redundant design”)
The special feature of the “neo-engines” is that the engine control unit monitors some
components and reacts automatically in case of an error:
Component(s)
Automatic
monitoring by the
ECU
Error detection, ECU reaction
and effects of errors
Engine temp.,
ambient air
temp. and
ambient air
pressure sensor
While the ECU is
turned on
If the signal is outside the acceptance range, a
default value is used. The engine is then
(restricted) operable. If the engine temperature
sensor is defective, the cold start behaviour is
bad. If the air pressure or air temperature sensor
is faulty, this leads to a loss of performance at
higher air temperatures and at higher altitudes.
Fuel pump
sensors
none
If a current sensor is defective, the affected
pump cannot be monitored. It is possible that an
error message concerning the pump is displayed
incorrectly.
Angle sensor
throttle valve
While ECU is
turned on
If the signal of one potentiometer (channel) is
outside the acceptance range, only the other is
used. In this case the engine can be operated
normally.
If both signals are within the rejection range, or if
they differ too much, a default value of 90° is
used. The engine can then only be operated at
full throttle.
RPM-sensor
and crankshaft
position sensor
While the engine
rotates
If the signal of a sensor is faulty, the
synchronisation of the affected channel is
restarted. If only the currently active (primary)
channel is affected, the system switches over to
the other one. Normally this has no effect to the
engine performance.
Only if both RPM-sensors fail, the motor cannot
be operated anymore.
Injection valves
During full throttle
operation
Both in full throttle operation and during starting,
the ECU changes the active injection channel at
regular intervals. At full throttle the engine speed
is monitored. If this speed drops, the ECU
switches permanently to the channel with higher
speed until the next restart.

2625 01i neo
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Service Manual
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Component(s)
Automatic
monitoring by the
ECU
Error detection, ECU reaction
and effects of errors
Fuel pumps
While the fuel
pumps are on (for
about 3 seconds
after switching on
the ECU & while
the engine is
rotating)
Both fuel pumps are operated in parallel and
monitored by their power consumption. The
engine is supplied with sufficient fuel even if only
one of the two fuel pumps is working properly.
The ECU sends a message via CAN for every detected fault (see engine manual and
CAN protocol). If the engine rotates, an additional message is stored in the internal error
memory.
Redundancy of the power supply:
The engine electrics can be supplied with sufficient energy from the battery as well as
from the generator. For the later the smoothing capacitor is required, see wiring diagram
supply.
Ignition redundancy:
The dual ignition system consists of two dual ignition coils, two ignition drivers integrated
in the engine control unit and four spark plugs. Each cylinder is always ignited twice per
revolution simultaneously on both ignition circuits –once near the TDC and once near
the BDC. If one ignition circuit fails completely or partially, the engine continues to run
with minimal loss of power.

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2625 02i neo
Service Manual
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Edition 1 dated 26.11.2020 page 11
3 Inspections and maintenance intervals
Daily pre-flight check
Before starting the engine:
−Check fuel supply.
−Check the movement of the throttle lever.
−Check the external condition of the engine and belt
transmission. Check for leaks.
−Ignition off. Turn the engine by hand at the propeller
and check noises or sluggishness.
−Check coolant level.
−Read out the error memory of the engine control unit.
Before take-off (with engine running):
−Check if there are already new error messages.
−Check ignition circuits individually at idle speed at
approx. 2300 rpm. Maximum speed drop 200 rpm.
Check every 25 hours or
once a year (the limit that
occurs first is decisive)
−General, thorough visual inspection: Look for loose or
missing parts and leaks.
−Check spark plugs.
−Clean engine and air filter.
−Lubricate starter gear teeth.
−Check all accessible screws and nuts for torque.
−Check cable pulls and actuations.
−Check cables and electrical connections, especially the
ECU power supply. To do so, temporarily pull the ECU
fuse 1 and check whether the control unit is still
supplied with power. Then repeat the same for ECU
fuse 2.
−During a test run turn off the main switch of the engine
system for a test. The engine must continue running.
Every 100 hours
Replacing the fuel filter of the fuel supply unit.
Every 400 hours
−Special check and general overhaul of the engine at the
manufacturer.
−We recommend checking the complete engine wiring
including connectors.
Engine preservation and
storage
If an engine is not operated for more than 2 months, it must
be preserved. To do so, inject 2.5ml of two-stroke oil into
the intake openings of the throttle valve sockets and turn
the engine on the propeller approx. 10 times.
Cover the inlet opening at the air filter.

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Service Manual
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Edition 1 dated 26.11.2020 page 12
4 Disassembly, check and assembly
4.1 Necessary tools, oil, adhesives and sealants
In order to carry out a professional repair or test, it is necessary to use faultless and
functional tools. In addition to the normal tool available in every engine workshop, the
following special tools and materials are required:
Pos.
SOLO order No.
Description
1
00 80 594
00 10 140
00 80 588
Puller for drive side
Cylinder screw M 12 x 50
Pressure piece
2
00 80 530
00 10 140
3 pcs. 00 10 150
Puller for generator bell
Cylinder screw M 12 x 50
Cylinder screw M 8 x 40
3
00 80 314
Pressure tester
4
Two-stroke oil Castrol Power 1 Racing 2T, SOLO two-
stroke oil or other oils with specification JASO FC or FD
5
00 83 177
Air filter oil
6
Loctite 243
7
Loctite 270
8
Loctite 574
9
Loctite 638
4.2 Tolerances for tightening torques
All tightening torques specified in this maintenance manual are nominal values. The
display deviation of the torque tools used must not exceed ± 5%.

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4.3 Engine
4.3.1 Disassembly of the engine
Pos.
Operation
Tools, aid
1
Clean engine before disassembly.
Fuel
2
Remove the injection system from the rubber
sockets.
Screwdriver
3
Unscrew exhaust pipe, remove adhering
residues and oil.
Allen key 6 mm
4
Loosen the fastening of the generator rotor and
pull off the rotor with a suitable puller.
Puller SOLO-No. 00 80 530
5
Remove the stator of the generator completely
and unscrew the mounting plate.
6
Loosen the hub on the drive side seated on the
crankshaft and pull it off with a puller.
Socket wrench 19 mm
Puller SOLO-No. 00 80 594
7
Loosen nuts on the cylinder head.
Socket wrench 13 mm
8
Lift and remove cylinder head.
9
Mark cylinder head, cylinder and piston for
matching.
10
Loose cylinder fixing nuts and lift off cylinder.
Open end spanner 12 mm
11
Disassemble the piston-pin lock carefully. Push
piston-pin out of the piston by hand.
12
Unscrew the side screws on the crankcase and
carefully disassemble the crankcase without
tilting the two halves. Clean both parts of the
crankcase.
13
Remove shaft seals, retaining rings and outer
rings of the bearings by hand.

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4.3.2 Check of the individual parts
Cylinder heads
−Carefully remove adhering combustion residues. Fuel can dissolve oil residues.
Scrape off stubborn oil carbon residues with a steel brush.
−Check both spark plug threads for damage.
−Clean the sealing surface.
Cylinder
−Visually check the cylinder surface (coating) for damage (scratches, rubbing,
scrapers).
−Measure the diameter of the cylinder in the direction of the crankshaft and
perpendicular to it:
Dimension
New
Wear limit
10 mm below top
76 mm +/- 0.005
76.01 mm
30 mm below top
76 mm +/- 0.005
76.01 mm
25 mm above bottom
76 mm +0.01
76.02 mm
−Visually check the grooves of the O-rings for the sealing of the cooling water jacket to
the cylinder head.
−Check the whole cylinder for cracks and damage to the sealing surfaces.
−Remove oil carbon residues on the coating and in the exhaust port.
Piston and piston rings
−Carefully remove any combustion residues adhering to the piston crown.
−Check piston diameter. Measure the diameter crosswise to the piston pin bore:
−Check the piston ring grooves. (vertical play of the piston rings)
oNew 0.05 mm –0.10 mm
oWear limit 0.20 mm
−Wear control of the piston rings.
oClearance (when the ring is inserted into the cylinder)
oNew 0.2 –0.35 mm
oWear limit 0.8 mm
−No light gap must be visible when the cylinder with inserted piston ring is held against
a light source.
Dimension
New
Wear limit
D1 = DN: 22 mm above bottom
76 mm +/- 0.06
75.9 mm
D2: 59.5 mm above bottom
76 mm +/- 0.08
75.8 mm
D3: 69 mm above bottom
76 mm –0.093
75.7 mm

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Service Manual
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Crankshaft
The crankshaft can only be disassembled by the manufacturer. However, the main
bearings (roller bearings) on the output side and on the ignition or generator side can be
replaced. For this purpose, the inner rings must be carefully ground down radially at one
spot until a maximum wall thickness of 0.3 mm remains. Then blast them with a chisel
and push them off the crank leg.
Check concentricity on centring block. The eccentricity at the bearings should not exceed
0.04 mm. If the eccentricity is greater, the shaft must be straightened by the
manufacturer. Check the axial play of the lower connecting rod bearings. This must be
between 0.35 and 0.5 mm.

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4.3.3 Assembly of the engine
The bearings of the crankshaft, as well as piston pin bearings and pistons must be
lubricated with two-stroke oil during assembly.
Operation
Tool, aid
1
Heat the inner rings of the roller bearings to 180°C and
push them onto the free ends of the crankshaft. The
collar must point towards the crank web.
Heating plate with
temperature control
2
Clean the crankcase with clean thinner. If necessary, first
remove any residues of the surface seal at the separation
point.
3
Coat the joining surfaces of the crankcase halves with
surface sealant and insert the crankshaft into the lower
part. Before doing so oil all bearings with two-stroke oil.
Insert all circlips as well as the shaft sealing rings.
Surface sealant,
Loctite 574,
Two-stroke oil
4
Put on the upper part of the crankcase and screw in the 4
screws on the side of the crankcase (with medium
strength Loctite) and tighten with a torque spanner.
Torque wrench
(12 Nm),
Loctite 243
5
Completely assemble the piston with rings and secure
with the retaining rings. Push the piston pin in by hand
and oil the piston and bearing with two-stroke oil.
Piston ring clamp bent
out of spring steel
6
Put on the cylinder and screw on with the nuts M8 so that
the cylinder can still be moved.
7
Screw the exhaust manifold to the gaskets to align
cylinders. Then tighten the lower cylinder base nuts.
Torque wrench
(20 Nm)
8
Assemble cylinder heads.
Torque wrench
(20 Nm)
9
Seal intake and exhaust openings with sheet metal part
in the shape of the flanges and with rubber plates (3 mm
thick). Check the engine for leaks with a leak tester. Test
pressure 0.5 bar. Pressure drop max. 0.1 bar / 5 min.
Pressure tester
10
Mount generator bracket. Secure screws with Loctite.
Torque wrench
(12 Nm), Loctite 270
11
Mount the rotor. Degrease the cone with thinner first.
Torque wrench
(80 Nm)
12
Mount the injection system on the intake manifold.
13
Mount air filter.
14
Leak test of the cooling water jacket for each cylinder
individually. Test pressure 1 bar. No pressure drop
allowed.
Pressure tester

2625 01i neo
2625 02i neo
Service Manual
SOLO
KLEINMOTOREN
GMBH
Edition 1 dated 26.11.2020 page 17
4.4 Throttle valve system 23 00 891 V1/V2
4.4.1 Hints for disassembly
−The throttle valve screws are caulked and must therefore be drilled out.
−The sensor guide bush is best removed by hand
using an M12 tap. However, it will be damaged
and must be replaced.
4.4.2 Check of the individual parts
Clean all parts and check for wear, cracks, corrosion and other damage. Replace if
necessary.
Wear limits:
1) Shaft bearings: Bearing bushings: 8.1mm, shaft: 7.92mm
2) spring wire holes: 1.55mm
4.4.3 Hints for assembly
−Aligning of the parts
The two sheet metal parts should be flush at the front and the rear.
The fuel distributor must fit tightly to
the flaps of the injector-side metal
sheet.
The axial clearance of the throttle shaft must be between 0.05 and 0.1 mm at
room temperature.
Areas of the same colour must be in
the same place.
The distance between the fuel
distributor and the throttle bodies
must be 26.6 ± 0.1 mm each.
The throttle valves must not touch or
rub against the throttle bodies when
fully closed.

2625 01i neo
2625 02i neo
Service Manual
SOLO
KLEINMOTOREN
GMBH
Edition 1 dated 26.11.2020 page 18
−Note: The holes in the sheet metal parts may be drilled out if necessary:
Through-holes M4 screws: max. 4.9mm, Through-holes M5 screws: max. 5.8mm.
−Thread lockage:
oAll M4 / M5 screws and the plug screws must be secured with Loctite 243.
oThe throttle valve screws must be caulked.
−Tightening torques:
oAll M4 screws: 3.5Nm;
Exception: mounting screws of the throttle position sensor: 1.8Nm
oAll M5 screws: 6.5Nm, plug screws: 12Nm
oThrottle valve screws: by hand
−Throttle valve angle sensor: The angle sensor must be aligned so that the signal voltages
of both potentiometers in the WinTrijekt status window are 4.56 ± 0.08 V when the
throttle valves are fully open.
4.5 RPM sensor
4.5.1 Hints for assembly
−The air gap between the sensor head and the studs on the
rotor of the generator must be 0.5 ±0.1 mm. This has to be
checked with a feeler gauge after mounting the speed sensor.

2625 01i neo
2625 02i neo
Service Manual
SOLO
KLEINMOTOREN
GMBH
Edition 1 dated 26.11.2020 page 19
4.6 Fuel supply system
4.6.1 Hints for disassembly
−The fuel pumps must be removed before the check valves can be unscrewed with an
Allen key 5mm.
−Attention! The spring which holds the fuel filter is tensioned.
4.6.2 Check of the individual parts
−Clean all parts and check for wear, cracks, corrosion and other damage. Replace if
necessary.
−It is recommended to replace the O-rings.
4.6.3 Hints for assembly
−Screw in the check valves up to the end of the thread. Apply Loctite only where the
valves will later be located.
−Do not install fuel pumps until the check valves have been mounted.
−Make sure that the O-rings are properly seated in the corresponding grooves.
−Do not use tension discs more than once.
−Make sure that the spring sits in the recesses provided for it.
−All screws and screw plugs as well as the check valves must be secured with Loctite 243:
−Tightening torques:
oScrew plugs: 12Nm
oBanjo bolts on the fuel pumps: by hand with a screwdriver.
oScrews M3: 1.4Nm
oScrews M4: 3.5Nm
oScrews M5: 6.5Nm

2625 01i neo
2625 02i neo
Service Manual
SOLO
KLEINMOTOREN
GMBH
Edition 1 dated 26.11.2020 page 20
5 Diagnosis and elimination of engine malfunctions
5.1 Basics
5.1.1 Handling with WinTrijekt NEO
To check the status of the ECU or to read the error memory, a computer with WinTrijekt
and a serial connection cable (RS 232) are required. If everything is connected correctly,
the engine control unit will connect automatically after power-up. Status windows and
access to the error memory are freely accessible, but for security reasons the functions
for clearing the error memory and changing the settings can only be carried out with a
password.
5.1.2 One important rule of thumb …
The vast majority of engine malfunctions are related to faults or defects in the wiring.
5.2 Error memory of the engine control unit
If the cause of the engine malfunction is not clear, the first thing to do is to read out the
error memory of the engine control unit. To do this, after establishing the connection,
select the menu item Error => Show error in the WinTrijekt main window and click on
reload in the newly opened window. The contents of the error memory are then displayed
on the screen.
Below are sone hints for troubleshooting, based on the entries in the error memory.
a) Injection system
Fuel pump 1
defective
•Temporary, irrelevant fault messages concerning the fuel
pumps can occur when the tank is (almost) empty.
•In unclear cases: During engine operation, observe the
current consumption of the corresponding pump via
WinTrijekt. Perform a control measurement with a
multimeter. If there is no measurement error, please
proceed as follows:
−Current consumption is OK again (the values in the
status window are black during operation): no action
required, if the error message does not occur again.
−Current consumption 0A: Check wiring and fuse.
−Current consumption >0A, but too high or too low (the
value in the status window is red): Check fuel pump.
Fuel pump 2
defective
Injection bench 1
defective
Check injection valves of the channel A and wiring with
multimeter. The resistance of one valve is approx. 12 Ohm.
Injection bench 2
defective
Check injection valves of the channel B and wiring with
multimeter. The resistance of one valve is approx. 12 Ohm.