JRM 250-10-106 Installer manual

Technical data Engine type 250-10-106
Engine Air-cooled, four stroke single cylinder, 1xOHC
mcc6.942emulovtpevS
6.35x0.77ekortsxeroB
1:0.41oitarnoisserpmoC
1-nim00201/Wk03rewopxaM
1-nim00021deepsxaM
Fuel Methanol
gk42thgieW
Spare parts catalogue
ENGINE TYPE
250-10-106
D-ANA s.r.o. - JRM Divišov e-mail:[e-mail]
Vlašimská 216 Tel.:+ 420317 721 649
257 26 DivišovTel.:[phone]
http://www.jawa.cz

Instruktion for Naitenance of Speedway Engine JAWA 250-10-106
The speedway engine Jawa type 250-10-106 is instended for junior speedway. Also for the adult long and
grass track racing events the engine can be used. The tuning of our engines for higher engine speed is to
the detriment of their service life interval and not allowed in junior speedway class. The engine fits into
standard JRM speedway chassi, only exhaust pipe diameter is smaller.
Description of engine JAWA type 250-10-106
The air-cooled single-cylinder, four-valve OHC, stroke volume 249.6 cm3, the bore 77.00 mm and
stroke 53.6mm. The crankcase, cylinder head and cylinder are made Aluminium-alloy. Cylinder has nicasil
couting. We do not supply overbore cylinders and piston as the engine is on the limit.
The crankshaft and connecting rod big end have cage-type needle bearings. The chain driven-camshaft is
supported in the cylinder head on needle bearings. The valves operated by rocker arm are at an angle of 35°,
the springs are cylinrical shape. The valve seats are hot-pressed into the cylinder heat.
The piston is a light alloy forging and carries two pistons rings. The circulation-system of lubrication is used.
Oil is sucked through filters into gear type oil pump and squeeze into crankshaft. The oil tank is situated in
the space between the valve gear cover and R.H. of the crancase, the oil filling is 0.6 l. The level must be
checked by the oil level indication before each race.
The engine is intended for the carburettor of diameter 34 mm and provided with electronic ignition,
Technical data
Bore/ stroke: 77.00/ 53.6 mm
Capacity: 249.59 cm3
Power 28-30 kW (38-41 bhp) at 10 200 rpm
Max. rpm: 12 000 rpm
Compression ratio: 14:1
Ignition: electronic Seletrra
Ignition Advance: 30°BTDC (adjustable 25°-30°)
Sparking plug: NGK RO 045-10, Champion G 55R
Fuel: Metanol
Oil : Castrol R SAE 40, Castrol 353, (0.6 l)
Measure at valve lift of 1 mm and at valve clearances inlet 0.1mm/ exhaust 0.15 mm (cold engine)
Valve timing - camshaft No.: 05
Exhaust open/ close 59°/24°
Inlet open/ close 26°/57°

Instructions for engine operation
Before puting an engine into operation and before each race are to be checked:
- valve clearence adjustment
- chain tension and tightening of screw on cam sprocked (in case of great chain clearence the valve timing
is to be checked)
- tension of primary and secondary chain
- clutch adjustment
- oil filling
- working order of ignition cut-out
- working order of icarburettor (free motion of slide valve)
Using of adequate thermal values of sparking plugs:
- colder for long tracks NGK RO 16 - 9, RO 045-9
- warmer for speedway NGK RO 16 - 10, RO 045-10
Before using the engine at full thorttle, the warming up of the engine is necessary. The choke may be used
only for a very short time. Starting is accomplished by pushing or rear wheel rotating. At cold engine
the choke is pulled out and starting without thorttle follows. The starting is made easier by "winding-up"
the engine first, i.e. slight turning of the rear wheel against the direction of turning until turning resistence
appears. Then the usual starting follows.
Setting-ap of ignition advance.
The full engine power output depends on a suitable adjustment of advanced ignition. The advanced ignition
of the engine occurs before the top dead center according to the table of technical data. The screw of checking
hole on the L.H. crankcase will be loosed, the crankshaft moved round a slight amound to the advanced
ignition mark in order to place it into the hole center. After releasing of screw turn slightli a stator in order
to make the checking line of the stator aligned with that of rotor. Then tighten the screws of stator.
Lubrication of engine
The circulation-system lubrication is used. Oil is sucked through rough filter into pump and squeeze into
crankshaft (connection rod big-and bearing lubrication). The rough oil filter must be check after first running
of new engine, and often clearing of this filter is recommended to avoid engine seizing. From crankshaft
space is oil returned to oil tank through reed valve. Oil filling is recommended to be replaced after five or
six heats.

Dismantling, assembly, adjustment and service life of engine
Cylinder heat and cylinder
Minimum thrust of valve springs when assembled has to be310 N - this thrust ensure maximum engine
speed 12 000 rpm. The valve springs are checked as follows: after dismantling of rocker arms the valve is
leant over suitable support against the plate of a balance and during the pressure of the head towards the
balance, the values in kg are read just in the moment when the valve starts opening. This value may not drop
below 31kg (310 N, spring monted length: 33.4-34mm). If the value is lower the valve springs must be
dismantled and check for free length, if the free length is not under 42 mm
(valid for springs 451 925 013 263) then spring may be underlaid but the minimum clearence 1 mm
between springs threads at complete valve lift must be observed.
_Width of intake seats 1.0-1.2 mm, round off the adges of valves and valve seats in the head.
_Rocker arm roller must run freely without grabbing
_Axial clearence of camshaft 0.2-0.4 mm
_Replace the valve upper plates aproximately atter 30 races
_Replace the camshaft drive chain aproximately after 30 races
_Combustion presure is sealet by silicon "O" ring
_Please replace the O ring during every engine overhaul.
_Compression ratio is adjusted by steel plates of different thickness under cylinder.
Cranh mechanism
Repair works of crank mechanism are recommended to be made in specialized repair shops. The crank
mechanism is pressed on cylindrical surfaces. Before pressing the interference size of pressed diameters
has to be checked. The flywheels are forged together with main pin like one piece, the interference of crank
pin at 0.11-0.13 mm. The crank mechanism can be pressed three times without using abnormal parts.
The crank pin can be ordered in an abnormal modification with greater pin diameter for presing by 0.025mm.
Axial clearence of crank mechanism in crankcase is 0.5-0.7 mm. Axial clearenceof connecting rod in
assembled crank mechanism should be 0.4 - 0.6 mm.
The balancing of crank mechanism for horizontal engine has to be 52% of balancing masses.
Clearence of gudgeon pin in piston must be 0.007 - 0.017 mm
Clearence in piston ring lock 0.3-0.35 mm
For safety reasons replace the big end connection rod bearing and pistons after 15 races. During this the
checking of connecting rod dimensions is recommended, the big end diameter should be 42.00/ 42.008 mm
(min/max), the radial clearence between crank pin and big end should be 0.037/ 0.052.
The clearence between piston pin and small end should be for connecting rod
881-12-110(143 mm lenght): 0.02-0.04 mm.
Asembly of crank mechanism
Before assembly all parts must be cleaned. The crank pin must be oriented according the oil hole in right
flywheel. During pressing the holes (pins) should be slightly oiled to prevent pressed serfaces from seizing.
After pressing balancing is necessary. Measurements are made in points and the run-out is measurd 5 mm
from flywheel faces and it should not exceed 0.03mm. The bighest value of run-out must be at the end
of crank pin.
The shaft of ignition rotor is carried separately in two bearings and is connected with the crankshaft
by a clutch. When dismantling the ignition the proper throwing of the shaft in the small valve gear during the
reassembly must be observed.
Valve gear mechanism
The camshaft is driven by chain directly from the crankshaft. The timing of valves is very easy, first by means
of chain on cam sprocket and then final timing by means of oval holes on cam sprocket. The tightening
of 4 screws on the sprocket must not be neglected. The values of cam timing are indicated in
technical data.

Výfuk a řetězy
250-01-005
Exhaust and chains
Auspuff und Kette
# Poz. Název Name Name
1 250-01-510 1 Výfukov trubka Exhaust pipe Auspuffrohr
2 889-01-050 1 Tlumič výfuku - KING Exhaust silencer Schalldämpfer
3 891-01-140 1 Z chyt tlumiče Exhaust bracket Dämpferhalter
4 871-01-011 1 Drž k tlumiče Silencer holder Halter
5 896-01-055 1 Objímka Clamp Klemme
6 896-01-056 1 Vložka Insert Büchse
7 896-01-057 1 Vložka se z vitem Insert with thread Büsche mit M6
8 250-01-011 1 Redukce výfukové trubky Insert of exhaust pipe Büchse Auspuffrohr
9 871-01-014 1 Drž k výfuku Exhaust holder Auspuffhalter
10 250-01-021 2 Drž k přední Front holder Auspuffhalter ( frontal)
11 273 188 901 014 2 Silentblok C 30/20 - 57777 Silentblock Buchse
12 871-01-013 1 Rozpěrka Spacer Distanzstück
13 893-01-032 1 V leček Roller Rolle
14 309 074 060 008 1 Šroub M6x8 Screw M6x8 Schraube M6x8
889-01-013 1 Těsnící šňůra Gasket Dichtschnur
15 961-56-415 2 Pružina Spring Feder
16 888-01-014 1 Drž k výfuku Exhaust holder Auspuffhalter
17 309 503 210 816 3 Šroub M8x20 ČSN 021103.59 Screw M8x20 Schraube M8x20
18 309 741 080 012 2 Šroub M8x12 FABORY 07 141 Screw M8x12 Schraube M8x12
19 309 543 210 620 1 Šroub M6x30 ČSN 021143.59 Screw M6x30 Schraube M8x30
20 311 129 221 080 5 Matice samojist. M8 ČSN 021492.29 Nut M8 Mutter M8
21 311 210 222 084 8 Podložka B 8.4 ČSN 021702.15 Washer B 8.4 Scheibe B8.4
22 889-01-520 1 Řetěz prim rní úplný 1/2''x5/16'' 64 čl. Primary chain Primärkette
318 988 901 012 1 Nýtovací čl nek 1/2" x 5/16" Chain joint 1/2" Shäckel 1/2"
23 250-12-030 1 Řetěz sekund rní úplný 5/8''x1/4'' 96čl. Sekondary chain Sekundärkette
24 318 989 001 042 1 Spojka řetězu 5/8''x1/4'' Chain joint Shäckel

Motorov skříň
250-11-007
Crankcase
Motorgehäuse
# Poz. Název Name Name
1 250-11-007 1 Motorov skříň Crankcase Motorgehäuse
2 889-11-510 1 Motorov skříň s pouzdry Crankcase with bushes Motorgehäuse mit Büchsen
3 309 543 210 618 2 Šroub M6x25 ČSN 021143.59 Screw M6x25 Schraube M6x25
4 309 543 210 626 3 Šroub M6x45 ČSN 021143.59 Screw M6x45 Schraube M6x45
5 311 214 023 061 5 Pružn podložka 6.1 ČSN 021740.09 Spring washer d 6.1 Federscheibe d 6.1
6 875-11-056 1 Pouzdro hlavního ložiska levé Main bearing bushing left Büchse link
7 875-11-021 1 Pouzdro hlavního ložiska pravé Main bearing bushing right Büchse recht
8 875-11-057 2 Šroub M6 Screw M6 Schraube M6
9 309 785 120 010 1 Z tka M12 x 10 FABORY 07850 Plug M12x10 Blindstopfen M12x10
10 875-11-058 2 Centr žní trubička D 14 Dowell pin Centrierrohr
11 889-11-513 2 Vložka oddychu Bush Buchse
12 889-11-514 3 Planžeta Plate Platte
13 889-11-515 3 Opěra planžety Stop of the plate Stütze
14 309 543 210 512 3 Šroub M5x12 ČSN 021143.59 Screw M5x12 Schraube M5x12
15 311 214 023 051 3 Pružn podložka d 5.1 ČSN 021740.09 Spring washer d 5.1 Federscheibe 5.1
16 889-11-516 2 Kolík D4x17.5 ČSN 022150.2 Pin D4x17.5 Stift 4x17.5
17 273 111 016 012 1 "O"kroužek 16x12 ČSN 029280.2 Rubber ring 16x12 Gummiring 16x12
18 880-11-025 4 Z vrtný šroub M10x154 Screw M10x154 Schraube M10x154
19 897-11-057 1 Podložka Washer Scheibe
20 898-11-022 1 Podložka d 35 Washer d 35 Scheibe d 35
21 311 733 100 400 1 Poj.kroužek D40x1.75 ČSN 02 2931 Circlip 40x1.75 Sicherungsring 40x1.75
22 311 733 100 350 1 Poj.kroužek D35x1.5 ČSN 02 2931 Circlip 35x1.5 Sicherungsring 35x1.5
23 273 521 106 205 1 Gufero s prachovkou 25x52x7 Shaft seal 25x52x7 Wellendichtringe 25x52x7
24 273 888 411 025 1 Gufero G 25x35x4 Shaft seal G 25x35x4 Wellendichtringe G 25x35x4
25 884-11-031 1 Napín k řetězu Tightener of the chain Spanner
26 884-11-032 1 Distanční trubička d 8.2 Spacing tube d 8.2 Distanzrohr 8.2
27 884-11-034 1 Napín k řetězu kr tký Tightener of the chain short Spanner kurz
28 884-11-035 1 Distanční trubička d 6.2 Spacing tube d 6.2 Distanzrohr 6.2
29 309 543 210 820 1 Šroub M8x30 ČSN 021143.59 Screw M8x30 Schraube M8x30
30 309 543 210 620 1 Šroub M6x30 ČSN 021143.59 Screw M6x30 Schraube M6x30
31 311 210 222 084 1 Podložka B 8.4 ČSN 021702.15 Washer B 8.4 Scheibe 8.4
32 311 210 222 064 1 Podložka B 6.4 ČSN 021702.15 Washer B 6.4 Scheibe 6.4
33 311 214 023 082 1 Pružn podložka 8.2 ČSN 021740.09 Spring washer 8.2 Federscheibe 8.2
34 311 214 023 061 1 Pružn podložka 6.1 ČSN 021740.09 Spring washer 6.1 Federscheibe 6.1
35 889-11-021 1 Víko rozvodu Cover of the timing gear Steuerungdeckel
36 324 160 030 026 1 Kuličkové ložisko 6003 2RS Ball bearing 6003 Kugellager 6003
37 273 888 020 284 1 Hřídelové těsnění GUFERO 20x28x4 Shaft seal G 20x28x4 Wellendichtringe G 20x28x4
38 627 889 811 024 1 Těsnění víka rozvodu Gasket of the timing gear Dichtung
39 898-11-023 2 Centr žní trubička Dowell pin Zentralrohr
40 309 543 210 620 4 Šroub M6x30 ČSN 021143.59 Screw M6x30 Schraube M6x30
41 309 543 210 622 2 Šroub M6x35 ČSN 021143.59 Screw M6x35 Schraube M6x35
42 309 543 210 630 1 Šroub M6x55 ČSN 021143.59 Screw M6x55 Schraube M6x55
43 898-11-037 1 Šroub napín ku Screw of the tensioner Spanerschraube
44 311 129 221 100 1 Matice samoj.M10 ČSN 021492.29 Nut M10 Mutter M10
45 889-11-031 1 Víko zapalov ní Cover of ignition Zündungdeckel
46 309 543 210 518 4 Šroub M5x25 ČSN 021143.59 Screw M5x25 Schraube M5x25
47 324 162 000 020 1 Kuličkové ložisko 6200 2RS Ball bearing 6200 Kugellager 6200