Weber Carburator Manual.pdf - Power by BMW E21

eturn spring (8 5) in the special hole.
3 Fit the bush (26). spring (2 5), washer (22), spring wa sher
(23) and nut (24) to the end of t he throttle shaft (84), then
tight en the nut (84 ) whilst ho lding the shaft stat ionary w ith a
screwdriver insert ed through t he toothed sector.
4 Tension the spring (85) by turning th e tooth ed sector, then
insert the th rottle valve into th e throttle shaft (84 ) and close th e
valve. Make sure that the angled perime ter of the valve seats
corr ectly in the barrel and allow it to snap shut several times to
centra lise it.
5 Insert the throttle valve retaining screws (29 } and tighten
t hem evenly but without exert ing excessive pressure on the
shaft . It is recomm ended that new screw s are alwa ys fitted to
avoid crcss-t hreacln q previous ly peened screws. Lock the
screws (2 9) by peening with W eber tool no 98010 900 whilst
supporting the shaft with a block of wood. Altematively, coat
the screw th reads with a liquid locking agent (fuel resistant)
prior to inserting them.
6 Insert the Teflon bushes (20 and 2 1) into th e primary
throttle shaft bore of the carburettor body (S6) and light ly
lubricate th em with a little engine oil. Not e that the smaller
bush (2 1) is located at the flo at chamber end.
7 Locate the spacer (30), spring (25) and bush (26) to t he
primary throttle shaft (27 ) w ith the smaller diameter of the
spacer against the accelerator pump operating cam.
S Insert the throttle shaft (27) into th e carburettor body from
t he float chamber side. making sure th at the Tefl on bushes are
not displaced (photo) .
9 W ith the accelerator pump cam facing the centre of the
float chamber, fit the bush (26 }, spring (2 5) and lever 0 5l.
making sure th at the th readed hole in the lever (75) is towards
t he secondary tooth ed sector (photos) .
10 Fit the bush (76) to the throttle shaft (27) then press on the
toothed secto r (83} and mesh it w it h th e secondary sector so
that th e alignment marks are in line (photo ).
o
9.8 Inserting the primary thro ttle shaft
(DGAS type}
9.10 Aligning th e toothed sectors
(DGAS type)
Part 2 Weber carburetors Chapter 9 9-23
9.9a Fittin g the spring to t he primary
throttle shaft (DGAS type)
9.14 Fitting th e sector adjustment screw
(DGA S type}
11 Fit the lever (77L tab w asher {79) and nut (7S}.
12 Locate the spring (74 ) on t he th rottle idling adju stment
screw (7 3), then insert the screw into t he carburettor body and
screw it in as far as it will go. The nut (78) may now be fully
tightened and the Iccktab (79) bent. Fully unscrew the adjustment
screw (73} but leave it in the carburettcr body.
13 Open th e prim ary throttle shaft (27) and insert the throttle
valve (28i, observing the procedure given in paragraphs 4 and 5
to centra lise it. Fit the ret aining screws (29).
14 Insert the sector screw (80) w ith tockw esher (81) and plain
wa sher (82) and tighten it w hilst holding both th rottle valves
compl etely shut ; this will synchronise the throttle valves
(photo).
15 Lubricate the toothed sectors with a little grease and check
that the throttle valves operate smooth ly and fully.
16 Fit the auxili ary veot urls (98) into their respective positi ons
as noted previously, making sure t hat t he supply chann els are
adjacent and th at th e nozzle cut away sections face the thrott le
valves.
17 If removed. locate the fast idle cam on the bush followed by
the spacer, then press t he bush onto the rear of th e automat ic
choke body (53) using a suita ble diameter length of tubing.
Not e t hat when fitted th e round contour of t he cam must face
the diaphragm end of the body with the flat edge upperm ost
(photo).
18 Fit th e screw (59) and plug (58 } to th e cover (5 6), posit ioning
the screw as previously noted.
19 Fit the operating rod (54) to t he body (53), et th e same time
locate th e diaphragm over the brass dowel.
20 Locate the spring (55) into the cover {56} then fit the cover
to the body making sure that the spring locates in th e
diaphragm plate.
21 Insert and tighten the retaining screws (57) evenly.
22 Insert the Teflon bearing (52) into the body (53).
23 Lightly lubricat e th e shaft l43) w ith engine oil and fit it in
9.9b Fitting th e lever to th e primary
t hrottle shaft (DGAS typ e)
_ 0 _
9.17 Correct location of th e fast idle
cam (DGAS type)
-