YAMAHA

Yamaha
ENGINES
YAMAHA
1976 AND LATER
E338, SS338 AN D SS433 TWO
CYLINDER MODELS
CONDENSED SERVICE DATA
Engine Model
Bore-(mm) . . .. . . ... . . . .. . . . ....
Inches ......... ....... ..... .
Stroke-(mm) .... . .. ... .. . . ... . .
Inches .. ........ . .. . .... ....
No. of Cylinders .. . . ... .... . ....
Displacement-co . . .. . . . . . .. . . . . .
E338
88338
88433
60
2.362
59.6
2.346
2
338
20 I).
Fr ee Air "
Mikuni (B)
1
60
2.362
59.6
2.340
2
338
20.63
Free Air
Keihin (PW)
1
68
2.677
59.6
2.346
2
433
26.4
Free Air"
Keihin (PW)"
1
Cubic Inches . . . . . . . . . ... . . .. .
CoolingType . ... . .. . ... ........
Carburetor Model.... . . .. . .. .
Number Used .... ..... , ......
Ignition:
, .... ... .
cm
Type .. . .. ..
Timing BT,_('
.............. 1.5-1.7 mm
Spark P'
, Li ........................ BR9EV""
Electrode Gap (mm) . ....... .
0.5-0.6t
0.020-0.024t
Inch . . . . . .... . . . .. .. . .. .
Fuel/Oil Ratio .... ... ..... . . .. . .
Autolube
·1·
cm
cm
1.6mm
1.6mm
BR9EV
0.5-0.6
0.020-0.024
Autolube
BR9EV""
0.5-0.6
0.020-0.024
Autolube
"Models prior to 1980 use Free Air cooling. All 1980-1981 models are equipped with
Axial Fan .
""Engine models prior to 1978 use Keihin (PW) model carburetors. All 1978-1981
models use Keihin (BD) model carburetors.
"""Models prior to 1980 use BR9EV. All 1980-1981 models use BR9ES.
tModels prior to 1979 use 0.5-0.6 mm (0.020-0.024 inch) electrode gap. All
1979-1981 models use 0.7-0.8 mm (0.028-0.031 inch) electrode gap .
MAINTENANCE
8PARK PLUG. Selection of spark
plug will depend upon type of service
and ambient temperature. Standard
plug is given in Condensed Service Data
table . Excessively cold weather and/or
light load conditions may require spark
plugs of warmer heat range. Hard
usage, heavy loads and warm weather
may require spark plugs of colder heat
range.
CARBURETOR. A Keihin (PW) type
carburetor is used on S8 models prior to
1978 and a Keihin (BD) type carburetor
is used on 1978-1981 SS models. A
Mikuni (B) type carburetor is used on
E338 models. Carburetor is installed on
a "Y" type intake manifold and provides
the fuel/air mixture to both cylinders.
Standard idle speed setting is 1,700 rpm
294
on E338 models, 2,000 rpm on S8338
models and 1,500 rpm on 88433 models.
Initial fuel/air mixture setting is as
follows:
Model
1976-1977
88338
88433
Model
Number
1976
SS338
SS433
155
155
1977
8S338
8S433
150
150
1978
S8338
8S433
E338
140
152
220
1979-1981
8S433
E338
145
240
Turns Out
1
P/4
1978
SS338
8S433
P /8
P/2
1979-1981
88433
16/8
1978-1981
E338
1
Standard carburetor main jet is as
follows:
If carburetor is removed for overhaul,
refer to LUBRICATION section for syn­
chronizing Autolube pump to throttle
opening.
Yamaha
ENGINES '
YAMAHA
1975 AND EARLIER
338,396 AND 433cc
TWO CYLINDER MODELS
CONDENSED SERVICE DATA
338,
396,
433
Engine Model
810
811,813
818
8ore-{mm)
.
60
65
68
Inches
.
2.36
2.56
2.68
Stroke-{mm)
.
59 .6
59 .6
59 .6
Inches
.
2.35
2.35
2.35
No. ofCylinders
.
2
2
2
Displacement-{cc)
.
433
338
396
20.6
24.1
26.4
Cubic Inches
.
Horsepower @ RPM:
28 @5500
30@5500
SL,SW ,EW
.. 24@5 500
36@6000
40@6500
.. 32 @6500
SS,GP
Cooling Type
. Cent. Fan Cent . Fan Cent. Fan
Carburetor Model
.
Keihin
Keihin or Mikuni
Diaphragm
Diaphr agm
lor 2
lor 2
• v. 2
Number Used
.
Ignition:
Type
.
Ener gy Tra nste r agneto
Point Gap
. See1'ext.
ext
See Text
No
No
Timing Advance?
.
No
Timing 8TDC
. Sf- ~ .\ t
See Text
See Text
Spark Plug:'
SL,SW,EW . .
NGK
NGK
NGK
87HZ
87HZ
87HZ
SS, GP
NGK
NGK
Champion
89H
87HZ
N2G
F , . I rude Gap (mm) . .
0.5-0 .6
0.5-0.6
0.5-0.6
I
, 't
\.
,.
. 0.020-0.024 0.020 -0.0 24 0.020-0.024
Autolube
20 :1*
20 :1*
' nch
.. ,lV"Oil Ratio
.
* If, not equipped with "Autolube".
MAINTENANCE
SPARK PLUGS. Selection of spark
plugs will depend upon type of service ,
ambient temperature a nd horsepower
of engine. Refer to 'Condensed Service
Fig. 1-Vlew showing checking and adJuslmenl
polnls fOI synchlon/z;ng carburelor opening 10
" Aulolube" 011 InJecl/on. Pump Is I//Ied from
nOlmal position to better show the mark . Refer
to text for ltie Iwo melhods of checkIng
adJuslment.
.
C. Clearance
M. Mark
288
N. Nula
T. Throttl e shan
Data for recommended plug for normal
use. Excessively cold weather and/or
light load conditions may require spark
plugs of warmer heat range. Hard
usage, heavy loads, warm weather and
higher horsepower may require spark
plugs of colder he at range :
CARBURETORS. Various carbure­
tors have been used. Refer to the appro­
pri ate carburetor paragraphs in FUN­
DAMENTALS section for carburetor
se rvice . For adjustment of carburetors
and "Autolube" refer to the appropriate
following paragraphs.
ONE (KEIHIN OR MIKUNI DIA­
PHRAGM) CARBURETOR. The car­
buretor is installed on a "Y" type inlet
manifold and provides the fuel-air mix­
ture to both cylinders. Initial fuel-air
mixture setting is as follows:
SL338 (Keih in )­
Idle mixture needle . . . 1 Va turns out
High speed
mixture needle .. .. . 1 V4 turns out
Fuel level (F- Fig. 1A) . .. .. 39 mm
Inlet lever height
(H-Fig. 1A)
5.7 mm
SW396 (Mik uni l-cIdle mixture needle .. . 1 14 turns out
High speed
mixture needle . . . . . 1% turns out
SW433, RW 433 (Mik uni) Idt uu xt ure needle . . . 1 Va turns out
I igh speed
mixture needle . .. . . 1 V2 turns out
On all models with one carburetor.
linkage adjustment is limited to syn­
chronizing the "Autolube" oil injection
to the carburetor throttle. With t~
carburetor throttle completely open
(maximum speed) and the pump con­
trol rod pulled to maximum position.
clearance (C- Fig. 1) should be 1-1.5
mrn (0 .04-0 .06 inch). Clearance is
measured between lower adj usting nut
and lever on carburetor. Adjustment is
accomplished by turning nuts to obtain
correct clearance.The top nut locks the
position onower nut.
Another method is to open throttle
completely and check to see ifoil pump
end of rod is aligned with mark (M). If
not relocate nuts (N). It will usually be
~
'f fl// 1110"~
Fig. 1A - Dlew/ng of Kelhln d/ephlllgm c"butt
tOI. Refel to text fOI distance (F) between c.nl.
of clllbuletol bOil and fuel Ilne/. Height (HI 01
fuel Inlet needle Is listed In text. Refe' to FU,.
DAMENTALS section fOI method of adJustmtllt
ERTER
Speed Tuning
st be remembered that the
lit is centrifugally controlled
Iriven unit responds, therefore
.ion and belt face width have a
.a ring on alignment of sheave
re . Two sheaves which are in
a lig n m e n t with correct belt
will move out of alignment if
omes too tight or too loose . Belt
a r or a belt of incorrect width
) change alignment and tension
ou gh shaft center distance and
re as specified.
lost models, the drive belt can be
e d with a minimum of disas­
by pulling the belt into bottom
ve of driven pulley then slipping
ff drive pulley. Installation is
~ of reinoval procedure.
-n belt is removed and/or unit is
' ~ m b l e d , inspect all components
carefully for wear or other damage . If
wear is abnormal, attempt to discover
the cause before completing the repairs
and returning the vehicle to service.
Excessive or uneven wear on sides of
vee belt may indicate pulley misalign­
ment, bent pulley half or improperly
adjusted idle speed. Examine pulley
faces for wear patterns or heat discolor­
ation. Determine and correct the cause
of trouble rather than just renew the
belt. Sheave parts should fit with a
minimum of clearance without
binding. Apply a light coating of oil or
low temperature grease to sliding
parts, but make sure that no excess
lubricant will be thrown on belt or
sheave faces when unit is in operation.
Check for specific overhaul informa­
tion and disassembly notes in the unit
sections or illustrations.
SPEED TUNING
GENERAL
, to rque converter unit is involved
.Y speed tuning decision for two
ns ; re sults and sa fety.
ere is little point in spending time
noney modifying and fine-tuning
ngine unless the drive trai n is
)!e of ma king t he bes t us e of i,h e
'power gained. The degree of mod­
l ion of the converter drive and
.n units is so inter-related that an
.t procedure cannot be outlined.
, sect ion , therefore , will attempt to
mly the principles which apply and
preca ut ions to be observed.
he high engine speeds associated
h performance tuning makes it
-era t ive that care be used in main­
ling the balance and trueness of
l ch components . Racing drive
ches should be equipped with a
tt er shield .
;peed tuning the converter unit gen­
l ly involves raising the engagement
-ed , ext r a attention to dynamic bal­
ce of the total unit, careful belt selec­
n, and combating down-shift lag of
iv en member. The final step in con­
rt er tuning is mating the drive unit,
It a nd driven unit into a carefully
.la nced package which will transm it
Igine power to the track in its most
fect ive form .
Although the principles of perform­
nee t u n i n g can be documented, so
'an y variables are involved that the
d ua l practice depends on experimen­
ation, experience and a feeling for the
ib (coupled with a fair amount ofluck)
hat only the outlines of procedure can
ie given .
DRIVE CLUTCH
Speed tuning an engine usually sac-
rifices torque at the low end to obtain a
power peak in the performance range.
The degree of "peakiness" depends on
the type of competition involved and
determines the tuning of the drive
clutch.
In a family machine, the drive clutch
sho uld enga ge smoothly at a relatively
low engine speed and u pshift smoothly
through the power range under all
combinations of throttle setting and
load . The converter package should
automatically shift down as necessary
to keep from lugging the engine.
With a "peaky" competition en gine,
engagement speed must be raised
above the stall-out point of engine
tuning and total balance of machine,
track surface and converter should
permit almost instantaneous accelera­
tion to peak horsepower range.
As previously stated, clutch engage­
ment speed can be raised by lightening
the centrifugal weights or by strength­
ening the reaction spring. Clutch and
machine manufacturers; and some perFig. 8-Cross sectional view
of governor centrifugal
weights showing: M-Face
movement and; Dotted
IInes-welght movement; to
high speed 'pos/ll on. Kidney
type weight Is shown at
right while left-hand view
shows curved cam-arm type
In which pivot (P) moves
and fulcrum (F) Is fixed.
Removing material In
shaded area (E) will have
greater effect on engage ­
ment speed; at shaded
area (X) will have greater
effect on shift pattern.
C.
F.
M.
P.
Gravity cente rli ne
Fulcrum point
Advan ce movem ent
Centrifugal pivot
formance specialists, make heavier
springs available. But sometimes the '
spring is not the whole answer. Centri­
fugal force increases geometrically as
speed increases and any inherent im­
balance is correspondingly multiplied.
Also , heavy centrifugal weights plus
high speed plus a correspondingly
strong balance spring in driven unit
exert heavy side pressure on drive belt,
resulting in increased belt wear and
frictional loss of power. For these rea­
sons, weight modification (or selection)
is also a widely used modification tech­
nique .
A new compensating spring for a
competition clutch should be com­
pressed in a vise overnight to pre-set
the spring before installation. Weights,
weight pins, rollers and similar parts
should be installed only in sets and
carefully weighed and balanced (using
druggists scales or equivalent) before
installation. :r weights are altered by
trimming, balance must be maintained
both as to total weight and configura­
tion. Dynamic balance and centrifugal
action are both affected by selection of
trim point. Refer to Fig. 8. As a general
rule, removing weight farthest from
pivot point (P ) , from hea.v.y side of
gravity centerline (C), or nearest
pulley outer rim will have the greater
centrifugal effect. And material nearer
pulley rim will "weigh more", "'.'n a
dynamic balance' st an dpoi u t t h a n
equal weight nearer the hub. Re­
moving weight at shaded area (E) will
affect engagement rpm to a greater
degree while removal from shaded area
(X) will have greater effect on shift
pattern. Do not remove material from
fulcrum point (F) of kidney weight
(right) or from roller contact area of
hammer weight (left) when lightening
the weights.
Paint, rust, gum or grease must be
removed from belt contact surfaces of
pulley faces and the surfaces kept
clean . Bushing surfaces, pivot pins,
rollers and other friction points must
\\
c
315
Carburetor malfun ctionin g can also
be cause d by worn parts . Needle valv e
and seat s hould be che cke d and
replaced as a unit if necessar y. Needle
valves should be checked for grooves
caused by overtig hte ning. Seats will
usu ally be damaged if thi s is th e case.
Needle valve adjusti ng should be done
lightl y to pr event needle and sea t
dama ge.
DISASSEMBLY. Refer to Fig. 4.
Remo ve retainin g scre w (15) and fuel
bowl (13). Knock out float pin and
remove float. Check float for dents,
leak s and wear on float lip or in float
pin holes. Remove inlet needle (9) and
seat (8). Remove idle mixture needle
(21), main fuel needl e (1 ) and springs .
Note cond ition of choke and throttle
s ha fts an d pl at e s. If we ar e xis ts,
ca r b ureto r body a s sembl y must be
r enewed .
r
s equ entially as thr ottl e s hut ter
moved from idle position , thu s sUPI
ing addit ional fuel for correct mixt
as air flow incr eases. At high s p«
th e prim ary venturi and main I
di schar g e nozzl e ar e brou gh t i :
oper at ion. s uppleme nting th e fuel wh
conti nues to flow through th e I
discharge ports. In thi s manner,
and air are balan ced throughout
operating range.
ADJUSTMENT
Carburet ors ar e divided into eo
and lat e typ es as out lined in introo
F uel level (Main) diaphragm (7- Fig.
5) is below fuel pump diaphragm (2). A
choke shutte r closes th e carbure tor air
horn to initiate th e star ting mode.
Slow sp eed oper ation is controlled by
settinz of idle adiust ment needle (l)
and
a se r ies of drilled dischar ge
ports (See Fig. 6) located below the
edge of closed throttle shutter. Dr illed
ports (three or four ) ar e uncovered
by
",'"
~
_ ~8
16~ 1).-9
18
KEIHIN diaphragm type carburetors
are designed for snowmobile use and.
prior to 1972 produ ction, wer e available
in two series; 406 which is roughly
equivalent in size and appli cati on to
Tillots on HR; and 407, equivalent to
Tillolson RD.
Starti ng with the 1972 model yea r , a
new method of identification was used
Model numb er of all carburetors begins
with prefix letters "CD," followed by a
numb er s uch as "33-28." First part of
numb er indicat es throttle bore (in milli­
met er s) and second part of numb er
indicates vent ur i diamet er .
OPERATION
~
:;-?\ 5
R
l;,r11r
made by bending t ang conta ct i
needl e valve. Install new fuel b:
gask et, fu el bowl, r etaining sc r
gasket (if needed), and retaining sen
Install main fuel needle. Install i
mixture needle . Do not overt igh:
needles in sea ts . Make running ad j i,
ments.
KEIHIN DIAPHRAGM CARBURETOR
1
~ · L.3 ~
19
ASSEMBLY. Install inlet sea t and
needle . Install float and float pin. Set
float level by inverting car bure tor with
float r esting lightly on inlet needle.
Measure between body gas ket flan ge
and float at th e point opposite th e
needl e valve . The measurement should
be 11/64 -in ch . Fl oat a dj us t me nt is
~:.;
C
Fig. 6- View of lower surface of cemu«
body showing idle bypass cover remove,
10
I. Gasket
I. Idle bypass cove r
P . Puls e pa­
X. Fu e l po r t
g-13
>-12
15~
-14
Fig. 4-Exploded view of typical Carter
Model UN " carburetor.
I. Main fuel needl e
2. Spr-ing
3.
4.
5.
6.
7.
8.
9.
10.
II.
12.
Car buretor body
Choke s ha ft
Choke disc
Choke det ent
Sea ling wash er
Inlet valve seat
Inlet va lve
F loat pin
F loat
Gasket
120
13.
14.
15.
16.
17.
18.
19.
20.
21.
F loat bowl
Sea lin/{ wash er
Retainer
Main jet
Pl u~
Spr ing
Idle sto p scre w
Th rottl e disc
Idle fuel needl e
~~ : ~h~~~fl e shaft
Fig. 5- View of Keihin Diaphragm Carburetor
showing points of adjustment.
A.
C.
H.
I.
L.
Adjusti ng st ud
Check plug
High spee d needle
Idle needl e
Locknut
R.
T.
2.
4.
7.
Ret urn fitti ng
Sig ht tu be
Fu el pum p diaphr agm
Lower gas ket surface
Operating diaphragm
Fig. 7- View of lower surface of cetbu «
body wi th Idle bypass cover (/) and exp
sian plug 1M) installed . Refer elsa to Fig .
Carburetor Service
'NGINES
nta cting
fuel bowl
g sc r e w
g screw.
tall id le
ertight e n
g adjust -
Dry paragraphs . Principles of adjus t­
lent are s imilar for all mod els but t he
recedure differs on ea r ly units wh ich
lave not been upd at ed. Th e CD units
~e show n in F ig. 5. On ea r ly unrnodi­
ned unit s , check plug (C) was t o th e
~gh t of re turn fittin g (R ), or bleed plu g
lretur n fittin g was not install ed . Most
early car buretors have been modifi ed
oy insta lling late fu el pump body, in
Ihich case carburetor will be adj us te d
~ a lat e un it.
shutter is
FUEL LEVEL. F ue l lev el mu s t be
us sup ply­
.ecked with eng ine ru nning. In st all
mixture
'gh speed , . ught t ube (T-Fig. 5) as show n, t he n
ilart and run e ng ine at a pprox ima te ly
main fuel
ught into 1500 rpm . Fuel lev el should r ise . in
jlast ic sigh t t u be t o low er g as ke t
fuel which
illJ'face of upper fuel pump cove r (4) .
the idle
n models with ea r ly fuel pump body
fuel
the sake sure sight t ube is inst alled in
IGHT port ope ning and ad j ust fuel
level to upper gask et sur face of upper
rover.
If fu el le vel is in corr e ct , loos en
Ocknut (L) and turn adj usting stud (A)
iN to RAISE fuel le vel or OUT t o
LOWER fu el le vel.
NOTE: Some early models rna
,ock screw (19-Fig. 12 )
c u re
idjusling stud (A- Fig. !; I I s tead of
bcknut (l).
, cor r ectl y. adj usted at
r aise re ar of machine a nd
... engine at 3000 r pm; fuel level
~o u l d not cha nge. If fuel le vel varies
cor rect adj ust me nt ca nno t be ob\, , ; . 1
J.
tain ed , overhaul ca r buretor as outlined
in appro pr iate following pa r agra phs .
MIXTURE ADJ USTMENT. Normal
int itial se ttings are 1 1/4-tu rns open for
idle mixture adj ustme nt scre w (I-Fig.
5) a nd one-t urn open for high speed
mix ture sc rew (H ). F inal adj us t me nts
mu st be made for best performan ce
wit h e ng ine at operating temperature
a nd fuel level properly adj us t ed . High
sp e e d m ix bure mu st be r e ch e ck ed
wh en ever idle mixture has been r ead ­
ju st ed .
OVERHAUL
To dis assemble th e Keih in diaphragm
ca r b u reto r, r em o v e th e s ix Phill ip s
head t hro ug h-bolts a nd carefully separ ­
a t e t he uni ts. Ch eck t hro ttle sha ft a nd
bor es for wear and t hro ttle s hut te r for
damage a nd r en ew t he car bure tor if
damage is found . Choke compo ne nts
are available and may he re newed ,
howe ver, new scre ws m ust be used a nd
s ta ked or i ns t all e d wit h "Locti t e ."
Rernovr l"g
speed adj us ti ng sc re w
(11 I
l ) and idle ad ju sting scre w (I ),
,1 ,1 : exa mine tapered e nds for dama ge.
Renew scre ws if tapered ends are
visi bly ri nge d or if ot herwise dam aged .
Ren ew car bure to r if adj us ti ng sc re w
seats are dam aged .
Rem ove idle by pass cover (I-Fig. 6)
a nd its gasket a nd examine idle we ll
a nd por t dr illings for dirt or gum. Soa k
in so lvent an d blow ou t with com ­
pr essed air if dep osits are found . Do
not use a drill or wir e probe in a n
attempt to clea n ports. Reinst all idle
bypass cover (I) as show n in Fig. 7,
tig hte ning retain ing scre ws sec ure ly.
Chec k mai n nozzle expansio n plu g (M)
to be s ure it is tight a nd correctly
install ed . Do not a t te mpt t o re move
expansio n plu g or ma in nozzle.
Wh en rea ssembling carburetor, fuel
ma in and id le s upply passage (X ) mu st
re mai n ope n. In stall gasket (1) a nd
pump diaph ragm (2-F ig. 8) making­
s u re hol e s for fu el passage s a lig n .
Install t he large "0" r ing (3) an d t he
tw o sma ll " 0" rings (in fue l ports " X " )
in fuel pump upper cover (4) and
p osition cove r ov er t he d ow el s in
throttle body .
Install chec k valv e (5- F ig. 9) making
sure th e th ree middl e fla ps are ce n­
t ered over inlet ports (IP) in upp er
cover (-1 ) an d t hat fuel ports (Xl a lig n.
T he six check flap s MUS T be in good
conditio n.
If inlet need le val ve seat is to be
r enewed , rem ove Phillips head scre w
(S-Fig. 10) a nd r etain er (R ). In vert
p ump body a nd rem ove va lve le ver,
spr ing a nd needl e va lve; t he n usin g a
Fig . 10-Top view of fuel pump tower
body (6) showing outlet port» (OP) and top
side of inlet valve seat (V). Seat i s secured
by tetsinet (R) and screw (S). Fuel passage
potts. ale at (X).
fig . 8-Fuel pump d iaphragm (2) installed
on carburetor body. Install large "0 " ring (3)
Ind small "0" ring on fuel ports (X) of fuel
pump upper cover (4).
Fig . 9-Fuel pump upper cover (4) installed
on carburetor body. Position check valve (5)
over upper cover with the three cente; flaps
centered over i n l e t ports (lP) and fuel
passages (X) open .
'
.
Fig . ll-Inlet valve lever button (B) should
be flush with ttoor on bottom side of val ve
body (6). Inlet valve seat is at (V) and in let
needle at (N).
121
Carburetor Service
ENGINE~
Fig . 14-Exploded view of
operating diaphragm (7),
spr ing (8), spring seat (9)
and regulator cover (10).
Upper end of adjusting
stud is shown at (A).
5---,.. . . ;--11
good pin punch of appropriate size,
drive valve sea t (V) 1I ,V•• >I out of
valve body. Valve h,ts are available
in sta ndard size and OD oversi zes of
0.01
, .d 0.002 mm. Oversize valves
"il t' iied by one or two annular
a
<J"'S around outside of body while
s ta ndar d body is s moot h. Rein stall
retainer (R-Fig. 10), needle valve and
lever, then check height of actuating
button (B-Fig. 11) which should be
flush with valve body floor. Adjust if
16
17
Fig. 12-Exploded view of
type carburetor showing
Sight tube (21) is used to
.
is not a part of the
KEIHIN
KEIHIN d iaphragm
component parts.
set fuel level and
carburetor.
TYPE FLOAT CARBURETOR
I. Throttle body
2.
3.
4.
5.
6.
7.
B.
9.
10.
11.
Low speed screw
High speed needle
Low speed need le
Pump diap hragm
Pump upper cover
Gasket
Pump check valves
Pu mp (regu lating) body
Inlet fitti ng
Inlet needle & seat
12.
13.
14.
15.
16.
17.
l B.
19.
20.
21.
Bleed plug
Spring
Pivot shalt
Valve lever
Regulatin g diaphrag m
Spri ng
Regulator cover
Lock screw
Adjust ing scre w
Sight tu be
ne cessary by bending t ang w hicl
contacts valve needle (N).
Fig. 13 shows operatin g diaphr agn
(7), spring (8) and spr ing seat (9
corr ectly positioned. Parts are show r
exploded in proper order in Fig. 14. Ar
initial starting point for adjus t ing st ue
(A) in regulator cover (1 0) is with tWI
thr eads showing when viewed fron
inside as shown. Adjust the assem bled
carburetor after installation as previ
ously outlined.
WITH BUTTERFLY THROTTLE
Carburetors are identified by a model
number which consists of a let ter prefix
"BD" followed by a set of numbers such
as "44-38". Fir st part of number in­
dicates throttle bore (in millimeters) and
second part of number indicates venturi
diameter.
IDLE MIXTURE. Idle mixture ae
justment is done by turning sere.
(6- Fig . 14A). Start engine and bring u
to normal operating temperature. Tur
screw either in (lean) or out (rich) to ot
tain an even engine idle. Readju st idl
speed to recommended setting after idl
mixture is set.
ADJUSTMENT
FLOAT LEVEL. Float is adjusted by
bending metal tang between float body
(16- Fig . 14A) and float pin (17). As
shown in Fig. 14B, distanc e (D) should
be 0.48-0.67 inch when carburetor is
tilted ~t a 20-30 degree angle.
Fig.13-0perating diaphragm (7) and associ­
ated parts installed on lower side of valve
body.
7.
B.
9.
F.
Oper ating diaphr agm
Spring
Spring sea t
Inlet fuel fitting
P . Pulse fitti ng
R. Return fittin g
X. Fuel passages
IDLE SPEED. Idle speed is adjusted
by turning screw (8-Fig. 14A). Idle
speeds vary from model to model, con­
sult resp ective manufacturer specifica­
tion for recommended speed setting.
MAIN JET. To insur e top perforn
ance of engine, main jet (13-Fig. 14..1
may need to be changed if there is :
2000 feet change in altitude or an 1:
degree F change in temperature. Whe:
altitude or weather temperature if
creases a lower number of jet should b
used. Whenever altitude or weathe
temperature decreases a larger numbe
of jet should be used. Caution should b.
taken especially when operating at .
lower altitude, too lean of fuel mixtur.
could shorten engine life.
122
.
•
..
~ ~'I~
'
"
......'
h.
: ,l......,,{.
"'~.
• .. tj;..~..
.."
\
~
.
RolI·Q·Flex, Rupp
VEHICL
---carburator--­
EngIne
Model
Make
Model
Diapl.
Make
Clutch
Sproc:ket
Chain
Ratio
Size
Model
SNit
Make
Cent.
Bo
Nun
RAIDER CONT.
1975
Eagl e . . . ... . . Kohler
Double Eag le . Ko hler
K340-2AS
K440-2AS
339cc
436cc
Walbro
WDA -38
13:29
Walbro
WRA -34(2)
15:31
NOTE: Production Discontinued.
312cc
339cc
398cc
436cc
290.1cc
339cc
398cc
436cc
339cc
398cc
436cc
Kelh ln
Ke lh ln
Keih ln
Kelh in
Kelh ln
Kelh in
Ke ln ln
Kelh in
Kelhln
Kelh ln
Ke ihln
SL292
SL292
SL29 2
338
396
433
396
433
292cc
292cc
292cc
338cc
396cc
43:
29;J
J it!
2cc
338cc
443cc
Kelh in
Kelh ln
Kelh ln
Kelh m
Keih ln
Kelti in
Kelhln
Kelh ln
Kelhln
Ke lh ln
Keih ln
40
428
Sal sbury 780
sa lsbury 850
14 :36
14 :36
15 :36
16 :36
14 :36
15 :36
16 :36
17 :36
14:36
15 :36
16 :36
35-2
35-2
35-2
35-2
35-2
35-2
35-2
35-2
35-2
35-2
35- 2
Eastern
Eastern
East ern
Eastern
Easte rn
Eastern
Eastern
Eastern
Eastern
Eastern
Eastern
14 :38
14 :36
14 :36
15 :36
16 :36
16 :36
16 :36
16 :36
14 :36
16 :36
17 :36
35-2
35-2
35-2
35-2
35-2
35-2
35-2
35-2
35-2
35-2
35-2
Yama ha
Yama ha
Yama ha
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
10 ¥- -11
10'4 -11
10'4 -11
10 '4 -11
14 : 36
15 :36
16 :36
16 :36
15 :36
16 :36
14 : 38
16 :36
17 :36
3502
35-2
35-2
35-2
35-2
35-2
35-2
35-2
35-2
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
Yama ha
10 '4 -11
10 '4 -11
15 :36
16 :36
16 :36
14 : 36
16 :36
17 : 36
14 :36
16 :36
35-2
35-2
35-2
35-2
35-2
35-2
35-2
35-2
Yama ha
Yamaha
Yam aha
Yam aha
Yamaha
Yamaha
Yamaha
Com et
11-11'/,
11-11 'I,
11-11 'I,
11-11 'I,
11-11 'I,
11-1I 'I,
11-11 'I,
11-11'1,
10 : 30
11 : 30
35-2
35-2
SalSbury
Salsbury
11
11;26
11 : 26
40
40
12.6
12.6
6008
6038
ROLL-O-FLEX
1971
Apache 312 .. .
Apache 340 . ..
Apache 400 . ..
Apache 440 . ..
Coma nche 295
Comanc he 340
Comanc he 400
Com anch e 440
Cherokee 340 .
Cherokee 400 .
Cherokee 440 .
CCW
CCW
CCW
CCW
CCW
CCW
CCW
CCW
CCW
CCW
CCW
Comanc he
292Y .. , ....
Comanche ChI
Apac he 292Y ..
A pac he 338Y . .
Apac he 396Y . .
Apa ch e 433Y ..
Cherokee 396Y
Cherokee 433Y
GT292SS ... ..
GT338SS .. . . .
GT433SS . . . ..
Yam aha
Yamah a
Yama ha
Yamaha
Yama ha
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
Yam aha
CCW312
' CCW340/ 1
CCW4oo /1
CCW440 / 1
CCW290 /1
CCW340 /1
CCW4oo /1
CCW440 /1
CCW340 /1
CCW4oo /1
CCW440 /1
CU34-406
CD34-406
CD34 -406
CD34-406
CD34-406
CD34 -406
CD34-406
CD34 -406
CD34-406
CD34-406
CD34-406
10 V,
10 '12
10 '12
lO V,
10 '12
10 V,
10 V,
10 V,
10 V,
10'12
10 '12
SV1::
SV13
SV13
SV13
SV13
SV13
SV13
SV13
SV13
SV13
SV13
1972
.J3
J_~
CD34-406
CD34-406
CD34-406
CD42 -38
CD42·38
CD42-38
CD42-38
CD42-38
CD42-38
CD34-406(2)
CD34 -406(2)
10'1,-11
10', , -11
10'4 -11
10'/, -11
10'/, -11
10 '4 -11
10 '4 -11
7148·
7148­
7148­
7148­
7148 ·
7148·
7148·
7148 7148
7148­
7148­
1973
c'
292
292c~
, "'"' he 396Y ..
Apa ch e 433Y : .
Cherokee 396Y
Cherokee 433Y
GT292SS .. . . .
GT338SS . . .. .GT433SS . . . ..
Yamatia
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
Yamah a
Yamaha
Yama ha
338
396
433
396
396
292
338
433
338cc
396cc
433cc
396cc
396cc
292cc
338c c
433c c
Ke:hlii
Keih ln
Keih ln
Kelh ln
Kelh ln
Kelh ln
Keih ln
Keih ln
Keih ln
A pache . .. . . . .
Apach e . .. . .. .
Apache . . . . ...
G .T. . . . . .....
G .T . . . . . . . . . .
G .T. . . . . .. . . .
Co man che . .. .
W ild One . . . . .
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
Yamaha
Yamah a
Kohl er
338Y
396Y
433Y
292S
338S
433S
292S
K340-2AS
339cc
396cc
433cc
292cc
338cc
433cc
292cc
338cc
Keihln
Keih in
Kelh in
Kelh ln
Kelh ln
Keih ln
Kelh ln
Dual M lkun i
j ~ Y ..
\.Iu.J..• .. VO
CD42 -38
CD42·38
CD42-38
CD42-38
CD42-38
CD42-38
CD42-38
CD42-38
10'/, -11
10 '/, -11
10'1, -11
10 '1,-11
10 '1, ·1 1
10 '4·11
10 '/, -11
7148·
7148·
7148·
7148·
7148­
7148­
7148­
714!l
7148·.
1974
407
407
407
407
407
407
407
1204·03C
1204· 030
1204-030
1204·03C
1204·030
1204·030
1204·03G
NOTE : Production Discontinued.
RUPP
ss II . .. . . . . .. JLO
SS III . . .. . . . . H irth
SS25O.. ... • .. JLO
SS3OO. . . .. . .. Hirth
Sport 281 . . _.. Sachs
G1"3OO . __ . . _. _ Sachs
S2B1 . . . . . . . . . SiGns
GT300 .. • . . . _.
5.iochs
G137V. . . . . . " 5.iochs
26
1966
L252
53R
247cc
300cc
Till otson
Tillotson
HL187A
HL2 14A
L252
53R
247cc
300cc
Tillotson
Tilloison
HL167A
HR3A
SA280
SA290
~
SA2!l()
SA370
I I V,
v,
11831
l 1H'1I
1967
ZTlcc
297cc
'1 '/,·
'I
If.'
1;'("11
I ;'IJ~ I
1968
T./lOl f>Vfl
TlI' CIlJVfl
m~
T,IICA3oVfl
297cc
T,lIo tsvn
TiliOlson
368cc
Own
Own
HL ~7&
H~1t
,:t~
,~
:til
'1', 1'
1' 111,
'JI, I'
/ ,,1
I I/I I,
/ v/
ur.
."yIf',."
.,y"
111',4
111',4
1Wh
Hk l~1t
HF!j(jA
HD14A
n.:as
l Z: 28
13;28
~z
J!r2
J!r2
(JIIII
Own
Own
I i l 'd
111\4
t,