Gearbox Component Clearances & Specs

The following list gives clearances and specs for gearbox components in a 1969 Triumph T120R.

57-0023 / T23
Bush, kickstarter spindle
BoreD 0.751-.752" Clearance .003-5" Spring Len 1/2"
Ref# 2   Fig.  9 Page 29 #7 (Qty:1)
 ¹ #7 reverses Ref# for 57-0043 & 57-0023

57-0057 / T57
Bush, gearshift quadrant (outer bush)
BoreD 0.7495-.7505" Shaft clearance .0005-.0025"
Ref# 3   Fig.  9 Page 29 #7 (Qty:1)
 ¹ #7 reverses Ref# for 57-0057 & 57-0023

57-0412 / T412
Bush, gearshift quadrant (inner bush)
BoreD 0.6245-.6255" Shaft clearance 0.0007-.0032"
Ref# 15  Fig.  7 Page 25 #7 (Qty:1)

57-0928 / T928
Bush, layshaft low gear
BoreD 0.8135-.8145" Shaft clearance 0.0025-45"
Ref# 8   Fig.  8 Page 27 #7 (Qty:1)

57-1370 / T1370
Bush, mainshaft high gear
BoreDia 0.8135-.8145" Clearance .0032-47" Len 2 19/32"
Ref# 4   Fig.  8 Page 27 #7 (Qty:1)
 ¹ Bush protrusion 7/16" before DU66247, none after)

57-0926 / T926
Layshaft low gear (30T)
BUSH bore dia:0.8135-.8145" BUSH clearance:0.0025-.0045"
Ref# 7   Fig.  8 Page 27 #7 (Qty:1)

57-2093 / T2093
LAYSHAFT, C/W HIGH GEAR (20T)
Dia:.6845"T.S./6850"D.S.;Len: 6 31/64"
Ref# 11  Fig.  8 Page 27 #7 (Qty:1)

57-0912 / T912
Locating peg, layshaft thrust washer
Dia:.07-.074" Length:.3135"(2).2585"/6.57mm(1)
Ref# 13  Fig.  2 Page 15 #7 (Qty:1)
 ¹ #7 calls for 1, 2 are required

57-2436 / T2436
MAINSHAFT C/W LOW GEAR (16T)
UNF Dia.DS-.8098/.8103";TS-.7494/.7498";Len:11 19/64";9/16-18UNF
Ref# 1   Fig.  8 Page 27 #7 (Qty:1)

57-2316 / T2316
Mainshaft high gear (26T)
Bore dia-.8135/.8145"; Clear-.0032/.0047"; Bush Len-2 19/32
Ref# 3   Fig.  8 Page 27 #7 (Qty:1)

57-1607 / T1607
Washer, thrust, gearbox inner cover, layshaft
New: .0905-.0910; Used 2018: .0938(outer)/.0916(inner spun)
Ref# 12  Fig.  7 Page 25 #7 (Qty:2)
 Orient: Grooved sides face AWAY from bearings