Fieldmaster Bottom End

For gasket sets click here; individual gaskets click here; rocker oil feed pipes click here; pistons click here; for oil, oil pipes and unions click here; for ball bearings click here.

It is a good idea to have the big-end eyes of alloy con-rods checked for ovality and it is imperative that the oil ways are cleaned out. When rebuilding the bottom end of a Fieldmaster or other engine with a plain timing side bearing we strongly recommend that the bushes are fitted to the crankcases and then ‘line bored’. This will ensure that they are in perfect alignment with the drive side roller main bearings, resulting in a perfect bottom end. We consider this money well spent for peace of mind and saves many hours of scraping in bushes, which is frequently required otherwise. The crankshaft end float should be .002”; shims are only available for increasing the end float, which is controlled by the timing side bush and oil seal washer 1180-37

Standard size of the big end crank journal is 1.375”; the timing side journal is 1.250”; con-rod big end eye diameter is 1.5002/1.5007”. Big end nut torque setting is 22 lbs/ft.

Prices of camshafts and followers are for exchange only, THIS MEANS THAT WE WANT YOUR OLD ONE FIRST. If the follower is badly worn there will be an extra charge to cover the cost of building it up, the cost is listed as 1750-94 in the price list and is per cam follower. The Fieldmaster camshafts always bend when they are heat treated and are always reconditioned by building up, which is included in the price. Additionally if the camshaft is worn where it runs in a bush or bearing there will be an extra charge for reclaiming it by industrial hard chrome plating it back to size, price is given by part number RES-14. This guarantees that you get a good cam. The profiles we use are close but not necessarily exact copies of the originals. We can recondition any cams not listed.

The 1948-53 dynamo strap fixing is awkward to use, life is made easier if the front stud is swapped for the later screw, K149-48.

Part No.

Description

Per

Years

PACK-ADV-003

500 / 650 Twin, Crank kitA

0137

Bolt securing crankcase halves, inside mouth21952-57

0520

Sump plate bolt41948-57

0520Q

Sump plate bolt, stainless41948-57

0538A

Bolt securing crankcase halves, inside mouth21948-51

67-1132

Sprocket, 18 tegs11948-57

940-38

Dome nut for breather11948-57

1095-29

Crankshaft and camshaft pinion nut31948-57

1131-37

Small end bush Later models did not have a bush in the rod.21948-53

1180-37

Oil seal washer11948-57

1180-49

Crankshaft oil seal11948-57

1450-37

Timing side bush, supplied rough machined for line boring after fitting see notes at the start of this section. (+.010” bushes also available for worn cases). There is sufficient white metal to allow boring to standard!11948-55

1450-56

Timing side bush with flange, as above11956-57

1557-36

Oil pipe union, delivery & return21955-57

2096-53

Fibre case screw washer (stops oil leaks)1948-57

2118-31

Tensioner blade, pin21948-55

2151-50

Oil pressure relief valve body, in crankshaft11948-57

2154A-50

Oil pressure relief valve spring, in crankshaft11948-57

2157-30

Magneto fixing nut31948-57

2157-30Q

Magneto fixing nut, stainless31948-57

5178-36

Rocker oil feed stud 1/4″11948-49

5178-50

Rocker oil feed stud 5/16″11950-57

5187-37

Rocker oil feed dome nut, 1/4″11948-49

5187-50

Rocker oil feed dome nut, 5/16″11950-55

5437-37

Dynamo strap trunnion21948-57

5890-35

Oil pipe union, short21948-52

5890-51

Oil pipe union, delivery & return21953

5895-35

Fibre washer21948-57

10418-54

Big end nut washer so that spanner will fit41948-57

10419-54

Big end nut, self locking type, cycle thread, not originally used 1947-54, see SN-341954-57

10419-54A

Big end nut, castle type (uses S17-1 split pin), cycle thread, see SN-341954-57

10471-54

Sprocket, 24 teeth Any FH sprocket can be fitted but do check the chain alignment and that there is space for the oil seal.11948-57

114500-48

Timing chain11948-57

K3-??

Crankcase, pairs, previously enjoyed11948-57

K5-48

Timing cover, “ARIEL TWIN”11948-49

K5-50

Timing cover, “TWIN”, brand new made by Ariel!11950-53

K5-54U

Timing cover, “KH”11954-57

K7-48

Camshaft bush, timing side21948-57

K9-48

Camshaft bush, drive side21948-57

K10-48

Half time pinion11948-57

K11C-55

Camshaft sprocket and pinion assembly, inlet, 59T (new)11948-57

K12-55

Exhaust cam pinion only, 57T with rivets, brand new11948-57

K13-48

Camshaft sprocket only21948-57

K22-48F

Cam follower (EXCHANGE)41948-49

K22-50F

Cam follower (EXHANGE)41950-54

K22-55F

Cam follower (EXCHANGE)41955-57

K23-48

Tappet guide41948-54

K23-55

Tappet guide41955-57

K25-48

Cylinder base stud, iron head models.81948-53

K26-48F

Camshaft, inlet (EXCHANGE)11948-57

K27-48

Camshaft, exhaust (EXCHANGE)11948-57

K29/35-48

Oil pump drive shaft with gear11948-57

K30-48

Dynamo strap11948-57

K31-48

Breather cap, without ball & spring, use S9-2 & 2154A-5011948-57

K32-48

Dynamo strap stud, front (later years used K149-48 screw, which is much easier to use)11948-53

K32-48

Dynamo strap stud, rear11948-57

K33-47

Cam follower circlip41948-54

K37-48

Oil pump drive spindle bush11948-57

K43-48

Dynamo strap saddle washer21948-57

K49-48

Tensioner blade11948-54

K49-55

Tensioner blade11955-57

K50-48

Tensioner blade spring11948-54

K51-48

Spring retaining sleeve nut11948-57

K57-48F

Oil pump, alloy, exchange only11948-50

K74-48

Magneto mounting stud31948-57

K84-48

Dynamo pinion, 22 Teeth11948-49

K84-50

Dynamo pinion, 24 Teeth11950-57

K98-48

Sprocket, 21 teeth11948-57

K110-48

Crankshaft (used)11948-57

K112-48

Sleeve for shock absorber11948-57

K113-48

Spring, shock absorber11948-49

K113-50

Spring, shock absorber11950-54

K113-55

Spring, shock absorber11955-57

K115-48/2

Shim, increases end floatAR1948-57

K115-48/4

Shim, increases end floatAR1948-57

K115-48/6

Shim, increases end floatAR1948-57

K116-48

Sump plate, stronger alloy version11948-57

K119-48

Sliding member11948-57

K130-48

Crankshaft sludge trap plug, large, 7/8″21948-50

K130-50

Crankshaft sludge trap plug, small, 5/821950-57

K131-48

Tensioner blade stop11948-54

K131-55

Tensioner blade stop11955-57

K132-48

Lockwasher, tensioner stud11948-57

K133-48

Crankcase tie stud, 1/4 x 1 11/1631948-57

K137-54

Connecting rod, late type that does not have a small end bush, complete with bolts etc. NEW21948-57

K138-48

Big end bolt, CEI thread (use 10419-54 nut)41948-57

K140-47/10

Big end shells (2 pairs) -.010″11948-57

K140-47/20

Big end shells (2 pairs) -.020″11948-57

K140-47/30

Big end shells (2 pairs) -.030″11948-57

K140-47/40

Big end shells (2 pairs) -.040″11948-57

K140-47/std

Big end shells (2 pairs) STD11948-57

K141-48

Main bearing, drive side, unbranded. For branded see K141-48B11948-57

K146-48

Push rod, iron head41948-53

K146-53

Push rod, alloy head41953-57

K149-48

Dynamo strap securing screw, front11954-57

K151Z-48F

Auto advance unit, EXCHANGE – you send us your old one and we send you a good ‘un.11948-57

K157-48

Stud for tensioner blade stop11948-57

K168-48

Spring retaining plate11948-52

K170-48

Spring for sump filter11948-57

K174-48/10

Camshaft shim, reduces end float by .010″1948-57

K196-51F

Oil pump, cost to recondition yours11948-57

K204-51

Oil pump screw41948-57

K233-53

Complicated head stud, not available, alloy head models81953-57

K261-56

Thrust washer distance piece to slider11956-57

K263-56

Oil seal distance washer11956-57

S1-3

Cylinder base nut, iron head models81948-53

S19-3

Cylinder base washer, iron head models81948-53

S17-1

Oil pressure relief valve split pin, in crankshaft11948-57

S18-1

Key for half time pinion and cam sprockets31948-57

S9-1

Oil pressure relief valve ball, in crankshaft11948-57

SN-3

Big end bolt nut, BSF, see 10419-54 for cycle thread version41948-54

Case Screws Individual screws may be ordered but for convenience the contents of each set are listed. Sets with a ‘Q’ suffix are in stainless steel.

FieldmasterSet No.03014014AK149-48K149-50
Length11/16”2”2 ¼”1 3/16”1 ⅝”
1948 <HT1681CS271121
1948 <HT1681CS27Q1121
1949-58CS041121
1949-58CS04Q1121

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