Carburetters - twin h4, hs4 and hs6 (special tuning)

Special Tuning Carburetters
We could not hope to cover all the SU carburetter specifications, both official and unofficial, that Minis have been fitted with over the years. What we can do though is to acknowledge the factory's own Special Tuning range, which we show here. Space precludes us from listing all the parts for these carburetters, so we have limited ourselves to showing complete carburetter assemblies, linkages, gasket kits, service kits, rebuild kits, sundries kits and a range of more frequently asked for parts. Most other parts are however available on request.

Identification of your carburetters is absolutely necessary before ordering parts. It should be a simple matter of looking at the aluminium tag attached to each float chamber lid; the number stamped on the tag should correspond to one of the carburetter part numbers listed here. Failing that, if the tag is missing, a study of the applications below will help.

H4 Carburetter Assemblies
One of Special Tuning's most popular products of the 1960s, the twin H4 (1 1/2") carburetter installation came in four different specifications: right hand drive or left hand drive with choke mechanism and right hand drive or left hand drive with thermo jet (without choke mechanism). The new replacement carburetter assemblies listed here are fitted with AUD1118 CP4 needles (AUD178 carburetters) or AUD1265 MME needles (AUD59 carburetters). Reconditionedcarburetters are available; please contact us for details.

The replacement twin H4 installations are faithfully original in appearance. They are supplied with inlet manifold and linkage, or as simply a pair of carburetters (with choke mechanism) or a pair of carburetters with linkage (thermo jet).

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
1	FZX3056	CARBURETTER INSTALLATION, replacement, H4	1	RHD; pair of AUD178 carburetters (with choke mechanism) complete with inlet manifold and linkage.
	FZX3075	CARBURETTER INSTALLATION, replacement, H4	1	RHD; pair of AUD59 carburetters (thermo jet) complete with inlet manifold and linkage.
2	AUD178T	CARBURETTERS, pair, replacement, H4	1	RHD; pair of AUD178 carburetters (with choke mechanism) without inlet manifold or linkage.
	AUD59T	CARBURETTERS, pair, replacement, H4	1	RHD; pair of AUD59 carburetters (thermo jet) without inlet manifold, but with linkage.
3	AUD178L	CARBURETTER ASSEMBLY, H4, left hand	1	RHD; with choke mechanism.
	AUD176/8R	CARBURETTER ASSEMBLY, H4, right hand	1	RHD; with choke mechanism.
	AUD176L	CARBURETTER ASSEMBLY, H4, left hand	1	LHD; with choke mechanism.
	AUD176/8R	CARBURETTER ASSEMBLY, H4, right hand	1	LHD; with choke mechanism.
	AUD59L	CARBURETTER ASSEMBLY, H4, left hand	1	RHD, thermo jet.
	AUD59R	CARBURETTER ASSEMBLY, H4, right hand	1	RHD, thermo jet.
	AUD165L	CARBURETTER ASSEMBLY, H4, left hand	1	LHD, thermo jet.
	AUD165R	CARBURETTER ASSEMBLY, H4, right hand	1	LHD, thermo jet.
Note that for the choke-fitted carburetters, the right hand carburetter is the same for both right hand drive and left hand drive, whereas the left hand carburetter is different (the float chamber changes from left hand mounting on right hand drive cars to right hand mounting on left hand drive cars).

H4 Linkage
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
4	AUC2431	ROD, throttle connecting	1
5	AUE75	COUPLING ASSEMBLY, throttle rod	2
6	AUE230	LEVER ASSEMBLY, throttle rod	1
7	AUC5062	TRUNNION ASS'Y, throttle cable to lever	1
8	AUE235	LEVER ASSEMBLY, throttle return spring	2
9	AUE92	STIRRUP ASS'Y, choke cable to jet levers	1	For AUD178 and AUD176 carburetters.
10	AUE34	TRUNNION ASS'Y, choke cable to stirrup	1	For AUD178 and AUD176 carburetters.

H4 Gasket, Service, Rebuild and Sundries Kits
A gasket kit includes manifold gasket, air filter gasket, suction chamber damper washer, float lid gasket, banjo connection washers, jet bearing washers and glands and float chamber hold up washers, for one carburetter.
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
11	AUE801	GASKET KIT, H4, choke mechanism type	2	For AUD178 and AUD176 carburetters.
	AUE901	GASKET KIT, H4, thermo type	2	For AUD59 and AUD165 carburetters.

A service kit includes the gasket kit, plus float chamber needle and seat and jet assembly, for one carburetter.
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
12	CSK40	SERVICE KIT, H4, choke mechanism type	2	For AUD178 and AUD176 carburetters.
	CSK42	SERVICE KIT, H4, thermo type	2	For AUD59 and AUD165 carburetters.

A rebuild kit includes the service kit, plus throttle spindle, throttle spindle bushes, throttle disc, throttle disc screws, jet lever and link fitting hardware (included in CRK205 only), throttle lever tapered pins and float lever pivot pin, for one carburetter.
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
13	CRK205	REBUILD KIT, H4, choke mechanism type	2	For AUD178 and AUD176 carburetters.
	CRK206	REBUILD KIT, H4, thermo type	2	For AUD59 and AUD165 carburetters.

A sundries kit includes suction chamber screws, float lid nut, gland spring, jet return spring, jet adjusting spring, jet sealing ring, jet locking nut, stop screw and spring, pivot bolt, banjo bolt, float lever (both types) and inlet filter, for one carburetter.
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
14	CSK001	SUNDRIES KIT, H type with choke mechanism	2	For AUD178 and AUD176 carburetters.
	CSK006	SUNDRIES KIT, H type with thermo jet	2	For AUD59 and AUD165 carburetters.

H4 Components
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
15	AUD9500	SUCTION CHAMBER ASSEMBLY	2
16	AUC2057	SCREW, locking needle	2
17	AUC8114	DAMPER, suction chamber	2
18	AUC4587	SPRING, piston, light blue	2
19	AUD1118	NEEDLE, jet, fixed, standard (CP4)	2	For 970cc with 12˚ BTDC static timing.
	AUD1265	NEEDLE, jet, fixed, standard (MME)	2	For 1071cc with 7˚ BTDC static timing.
	AUD1067	NEEDLE, jet, fixed, standard (BG)	2	For 1275cc with 5˚ BTDC static timing (C-AEA648 camshaft).
	AUD1006	NEEDLE, jet, fixed, standard (No. 7)	2	For 1275cc with 2˚ BTDC static timing (C-AEG510 camshaft).
20	WZX1595	JET ASSEMBLY, choke mechanism type	2	For AUD178 and AUD176 carburetters.
	AUC8188	JET ASSEMBLY, thermo type	2	For AUD59 and AUD165 carburetters.
21	AUC3230	BEARING, jet, upper	2
22	AUC3231	BEARING, jet, lower	2	For AUD178 and AUD176 carburetters.
	AUC4656	BEARING, jet, lower	2	For AUD59 and AUD165 carburetters.
23	WZX1303	FLOAT KIT	2	Includes float lid gasket.
24	WZX1101	NEEDLE AND SEAT ASS'Y, float chamber	2	Includes float lid gasket.
25	AUC1051	TAG, carburetter identification	2
AUC1051 is a blank tag; when ordering, please state the carburetter assembly number you require stamped on the tag.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
26	WZX987	THROTTLE SPINDLE KIT	2
A throttle spindle kit includes throttle lever taper pins, throttle disc screws, manifold and air filter gaskets.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
27	AUD3080	BUSH, throttle spindle	4
Note that the throttle spindle bosses on the carburetter body must be reamed to 9.5mm diameter before fitting bushes.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
28	WZX1323	THROTTLE DISC KIT	2
A throttle disc kit includes throttle disc, throttle disc screws, manifold and air filter gaskets.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
29	12G2125	GASKET, air filter	2
30	AUC4278	GASKET, manifold and insulator	4
31	LNZ206	NUT, nyloc, carburetter to manifold	4
32	PWZ106	WASHER, plain	4

HS4 and HS6 Carburetter Assemblies
In the 1970s, Special Tuning offered a choice of twin HS4 (1 1/2") or twin HS6 (1 3/4") carburetters for use on 998cc and 1275cc Minis (HS6s were available for 1275cc only). Earlier carburetters were of the fixed needle type and later versions had 'swing' or biased needles. The new replacement HS4 carburetter assemblies listed here are of the biased needle type. No Special Tuning HS4 or HS6 carburetters were manufactured with Capstat temperature compensating jets. Reconditioned carburetters are available; please contact us for details.
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
	FZX3054	CARBURETTER INSTALLATION, twin HS4	1	Includes a pair of AUD640 carburetters, linkage, fuel lines, manifold and heatshield assembly.
33	FZX3050	CARBURETTERS, pair, replacement, HS4	1	Pair of AUD640 carburetters with linkage.
34	AUD224R	CARBURETTER ASS'Y, HS4, right hand	1	Fixed needle type.
	AUD224L	CARBURETTER ASS'Y, HS4, left hand	1	Fixed needle type.
	AUD640R	CARBURETTER ASS'Y, HS4, right hand	1	Biased needle type.
	AUD640L	CARBURETTER ASS'Y, HS4, left hand	1	Biased needle type.
	AUD709R	CARBURETTER ASS'Y, HS4, right hand	1	Biased needle type.
	AUD709L	CARBURETTER ASS'Y, HS4, left hand	1	Biased needle type.
	AUD416R	CARBURETTER ASS'Y, HS6, right hand	1	Fixed needle type.
	AUD416L	CARBURETTER ASS'Y, HS6, left hand	1	Fixed needle type.
	AUD641R	CARBURETTER ASS'Y, HS6, right hand	1	Biased needle type.
	AUD641L	CARBURETTER ASS'Y, HS6, left hand	1	Biased needle type.

HS4 and HS6 Linkage
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
35	AUE481	ROD, throttle and choke connecting	2	HS4 carburetters.
	AUC2439	ROD, throttle and choke connecting	2	HS6 carburetters.
36	AUE586	LEVER ASSEMBLY, pick up, LH	2
37	AUE587	LEVER ASSEMBLY, pick up, RH	2
38	AUE180	LEVER ASSEMBLY, throttle	1
39	AUC5062	TRUNNION KIT, throttle cable	1
40	AUE34	TRUNNION AND SCREW, choke cable	1

HS4 and HS6 Gasket, Service, Rebuild and Sundries Kits
A gasket kit includes manifold gasket, air filter gasket, suction chamber damper washer, float lid gasket and jet union washer and seal, for one carburetter.
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
41	AUE811	GASKET KIT, HS4 carburetter	2	For AUD224, AUD640 and AUD709 carburetters.
	AUE812	GASKET KIT, HS6 carburetter	2	For AUD416 and AUD641 carburetters.

The service kit for the Special Tuning HS4 carburetters includes two gasket kits, plus float chamber needles and seats, one each AUD9141 and AUD9142 jets and clips for the jet pick up links, for two carburetters.
The HS6 service kit includes two gasket kits, plus float chamber needles and seats, jet assemblies and clips for the jet pick up links, for two carburetters.
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
42	CSK59	SERVICE KIT, pair of HS4 carburetters	1	For AUD224, AUD640 and AUD709 carburetters.
	CSK55	SERVICE KIT, pair of HS6 carburetters	1	For AUD416 and AUD641 carburetters.

Each rebuild kit includes the service kit, plus throttle spindles, throttle spindle bushes, throttle discs and throttle disc screws, for two carburetters.
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
43	CRK254	REBUILD KIT, pair of HS4 carburetters	1	For AUD224, AUD640 and AUD709 carburetters.
	CRK249	REBUILD KIT, pair of HS6 carburetters	1	For AUD416 and AUD641 carburetters.

The sundries kit includes choke cam pivot bolt and tubes, suction chamber screws, float lid screws and washers, stop screws and springs, jet nut, jet spring and washer, spindle lock tab and float pivot pin, for one carburetter.
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
44	CSK003	SUNDRIES KIT, HS type carburetter	2

HS4 and HS6 Components
Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
45	AUD9635	SUCTION CHAMBER ASSEMBLY	2	For fixed needle HS4 carburetters.
	AUD9988	SUCTION CHAMBER ASSEMBLY	2	For biased needle HS4 carburetters.
	AUD9187	SUCTION CHAMBER ASSEMBLY	2	For fixed needle HS6 carburetters.
	AUD9999	SUCTION CHAMBER ASSEMBLY	2	For biased needle HS6 carburetters.
46	AUC2057	SCREW, locking fixed needle	2	Included in HS4 and HS6 fixed needle suction chamber ass'ys.
	AUD4251	SCREW, locking biased needle	2	Included in HS4 biased needle suction chamber assembly.
	AUD4252	SCREW, locking biased needle	2	Included in HS6 biased needle suction chamber assembly.
47	AUC8114	DAMPER, suction chamber	2
48	AUC4587	SPRING, piston, light blue	2	For HS4 carburetters.
	AUC4387	SPRING, piston, red	2	For HS6 carburetters.
49	AUD1006	NEEDLE, jet, fixed, standard (No. 7)	2	For fixed needle HS4 carburetters.
	CUD1015	NEEDLE, jet, biased (AAR)	2	For biased needle HS4 carburetters.
	AUD1247	NEEDLE, jet, fixed, standard (KW)	2	For fixed needle HS6 carburetters.
	CUD1151	NEEDLE, jet, biased (BCD)	2	For biased needle HS6 carburetters.
50	AUD9102	JET ASSEMBLY, RH	2	For HS4 carburetters; black coloured jet body with black identification sleeve. Original specification item.
	AUD9141	JET ASSEMBLY, RH	2	For HS4 carburetters; black coloured jet body with green identification sleeve. Alternative specification item.
	AUD9098	JET ASSEMBLY, LH	2	For HS4 carburetters; black coloured jet body with white identification sleeve. Original specification item.
	AUD9142	JET ASSEMBLY, LH	2	For HS4 carburetters; black coloured jet body with pink identification sleeve. Alternative specification item.
	AUD9149	JET ASSEMBLY, RH	2	For HS6 carburetters; black coloured jet body with orange identification sleeve.
	AUD9148	JET ASSEMBLY, LH	2	For HS6 carburetters; black coloured jet body with yellow identification sleeve.
51	WZX1341	JET BEARING KIT	2	For fixed needle carburetters.
	WZX1340	JET BEARING KIT	2	For biased needle carburetters.
52	WZX1300	FLOAT KIT	2	Includes float lid gasket.
53	WZX1100	NEEDLE AND SEAT ASS'Y, float chamber	2	Includes float lid gasket.
54	AUC1038	TAG, carburetter identification	2
AUC1038 is a blank tag; when ordering, please state the carburetter assembly number you require stamped on the tag.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
55	WZX1177	THROTTLE SPINDLE KIT	2	For HS4 carburetters.
	WZX1178	THROTTLE SPINDLE KIT	2	For HS6 carburetters.
A throttle spindle kit includes throttle lever taper pins, throttle disc screws, manifold and air filter gaskets.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
56	AUD3080	BUSH, throttle spindle	4
Note that the throttle spindle bosses on the carburetter body must be reamed to 9.5mm diameter before fitting bushes.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
57	WZX1323	THROTTLE DISC KIT	2	For HS4 carburetters.
	WZX1321	THROTTLE DISC KIT	2	For HS6 carburetters.
A throttle disc kit includes throttle disc, throttle disc screws, manifold and air filter gaskets.

Ill. No.	Part No.	Description	Qty. Rqd.	Remarks
58	12G2125	GASKET, air filter	2	For HS4 carburetters.
	AUC1283	GASKET, air filter	2	For HS6 carburetters.
59	AUD2219	GASKET, carburetter to manifold	2	For HS4 carburetters.
	GUG705561	GASKET, carburetter to manifold	2	For HS6 carburetters.
60	LNZ205	NUT, nyloc, carburetter to manifold	4/8	Qty. increases for HS6 carburetters.
61	PWZ105	WASHER, plain	4/8	Qty. increases for HS6 carburetters.

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Carburetters - twin h4, hs4 and hs6 (special tuning)

STAMPED HS CARBURETTER TAG. State number when ordering

THROTTLE SPINDLE KIT-SINGLE H4 CARBURETTERS

JET ASSY.-H4 CARBURETTERS WITH CHOKE MECHANISM

JET BEARING KIT-FIXED NEEDLE HS CARBURETTERS

USE: WZX1442

THROTTLE DISC KIT-H4 & AUD170,250,393 &453 HS4 CARBS

THROTTLE DISC KIT-HS6 CARBURETTERS

FLOAT KIT-H4 CARBURETTERS

FLOAT KIT-'STAY UP' ALL HS CARBURETTERS

THROTTLE SPINDLE KIT-HS6 CARBURETTERS

THROTTLE SPINDLE KIT-HS4 CARBURETTERS

NEEDLE AND SEAT KIT-H4 CARBURETTERS

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