BSA Bantam Repair Workshop Manual 1948-1971

The 1948-1971 BSA Bantam Repair Manual by Haynes covers the following motorcycle models:

• BSA D1, 123cc 1948-1962
• BSA D3, 148cc 1953-1957
• BSA D5, 174cc 1957-1958
• BSA D7, 174cc 1958-1966
• BSA D10, 174cc 1966-1967
• BSA D14/4, 174cc 1967-1968
• BSA DeLuxe, 174cc 1964-1966
• BSA Sports, 174cc 1966-1967
• BSA Supreme, 174cc 1966-1967
• BSA Trials, 123cc 1949-1955
• BSA Bushman, 174cc 1966-1968
• BSA Silver Bantam, 174cc 1965-1967
• BSA D175, 174cc 1969-1971

Book Excerpt: 1948-1971 BSA Bantam Repair Workshop Manual ENGINE, CLUTCH AND TRANSMISSION UNIT

CRANKCASES | EXAMINATION AND RENOVATION

1. Inspect the crankcases for cracks or any other signs of damage. If a crack is found, specialist treatment will be required to effect a satisfactory repair.
2. Clean off the jointing faces, using a rag soaked in methylated spirit to remove old gasket cement. Do not use a scraper because the jointing surfaces are damaged very easily. A leak-tight crankcase is an essential requirement of any two-stroke engine. Check also the bearing housings, to make sure they are not damage. The entry to the housings should be free from burrs or lips.
3. Do not forget to check also the generator inner and outer covers and the primary drive cover. Good jointing surfaces are essential especially in the case of the generator inner and outer covers that have no intermediate gasket.

TRANSMISSION COMPONENTS

EXAMINATION AND RENOVATION

1. Examine carefully the gearbox components for signs of wear or damage such as chipped or broken teeth on the gear pinions and kickstarter quadrant, rounded dogs on the ends of the gear pinions, bent selector forks, weakened or damaged springs and worn splines. If there is any doubt about the condition of a part, it is preferable to play safe and replace the part at this stage. Remember that if a suspect part should fail later, it will be necessary to completely strip the engine/gear unit yet again.
2. It is advisable to replace the kickstarter return spring irrespective of whether it seems to be in good condition. This spring is in constant use, yet if it has to be replaced at a later date, a certain amount of dismantling is necessary in order to gain access. It is cheap and easy to replace at this stage.
3. Do not forget to examine also the kickstarter ratchet assembly, which is held to the back of the clutch drum assembly by a circlip. Examination will show whether the ratchet teeth have worn, causing the kickstarter to slip or whether the ratchet teeth have worn, causing the kickstarter to slip or whether the outer teeth are damaged, causing the kickstarter quadrant to jam. Note that the leading tooth of the quadrant is relieved, to help offset the tendency to jam during the initial engagement.

FRAME AND FORK ASSEMBLY

CENTERSTAND | EXAMINATION

1. The centerstand is attached to a lug on the bottom frame tube, to provide a convenient means of parking the machine on level ground. It pivots on a long bolt that passes through the lug, secured by a nut and washer. A return spring retracts the stand when the machine is pushed forward, so that it can be wheeled prior to riding.
2. The condition of the return spring and the return action should be checked regularly, also the security of the retaining nut and bolt. If the stand stops while the machine is in motion it could catch in some obstacle in the road and unseat the rider.

Subject: 1948, 1949, 1950, 1951, 1952, 1953, 1954, 1955, 1956, 1957, 1958, 1959, 1960, 1961, 1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969, 1970, 1971 BSA Bantam motorcycle service, maintenance, repair. ISBN-10: 0856961175 | ISBN-13: 9780856961175 | Haynes 117