BSA Clutch Spring Conversion
BSA six spring clutch to four or three spring Triumph clutch
Our #42-3170/A hub for three or four spring clutches is better than the original #42-3170.
It is designed for use with thrust washers #57-3931 or #57-3931/A (has a 1/2" bigger OD, and six oil holes in the thrust surface).
SRM design ensures that the chainwheel is supported from wobble by the thrust washer.
Recommended to use in conjunction with SRM needle roller lift clutch pressure plate.
The centre adaptor is to fit the BSA A7/A10/Goldstar swingarm gearbox shaft.
It then takes the stock four spring BSA/Triumph clutch with solid centre, or can fit the later T120/T140 three spring clutch.
Options are as below:
(A) Convert to three spring Triumph clutch by purchasing the following components:
As you are retaining the crankshaft cush drive, the additional clutch cush centre with rubbers will give you an extremely smooth bike!
(20) #57-0394 ROLLERS
(1) #42-3170/A ADAPTOR
(1) #57-3931 WASHER OR #57-3931/A WASHER
(1) #57-4435 CLUTCH CENTRE ASSEMBLY WITH RUBBERS
(3) #57-1560 SPRING
(3) #57-2526 NUT
(3) #57-4754 BOLT
(3) #57-1931 CUP
(1) #57-2156 PRESSURE PLATE WITH #57-2159 ADJUSTER AND #14-0403 NUT, OR:
(1) #57-2156/A ALLOY PRESSURE PLATE COMPLETE WITH NEEDLE BEARING
(1) #42-3274 CLUTCH PUSHROD
(1) #42-3267 NUT
(1) #57-0420 WASHER
(1) #57-0524 TAB WASHER
(6) #57-1362/E CLUTCH FRICTION PLATE, HEAVY DUTY
(6) #57-1363 PLAIN CLUTCH PLATE
Or (B) Convert to a four spring clutch with solid clutch centre:
(20) #57-0394 ROLLERS
(1) #42-3170/A ADAPTOR
(1) #57-3931 WASHER OR #57-3931/A WASHER
(1) #57-0872 SOLID CLUTCH CENTRE, 4 SPRING
(4) #57-1560 SPRING
(4) #57-2526 NUT
(4) #57-4754 BOLT
(4) #57-1931 CUP
(1) #57-0986 PRESSURE PLATE, CL, P.U. TRI/BSA, 4 SPRING, OR:
(1) #57-0986/A ALLOY PRESSURE PLATE COMPLETE WITH NEEDLE BEARING
(1) #42-3274 CLUTCH PUSHROD
(1) #42-3267 NUT
(1) #57-0420 WASHER
(1) #57-0524 TAB WASHER
(6) #57-1362/E CLUTCH FRICTION PLATE, HEAVY DUTY
(6) #57-1363 PLAIN CLUTCH PLATE
Or (C) The ultimate solution:
Convert to a belt drive with option (A) above, but omit the clutch plates, as the belt drive comes complete with eight plain and eight friction plates!
Then purchase the additional parts for a four or three spring clutch for the belt drive.