BSA Motorcycles 1950s

Today in Motorcycle History

Modern Improvements to BSA A10 parts

A number of parts are currently in production today which are superior (at least in my opinion) to the original A10 parts. I have tried to summarize some of these parts and some sources for these parts here. If you order from any of these folks, be sure to tell them where you found out about them (none of these are paid advertisers so I am doing them a favor).

Quartz Halogen Headlight bulbs to fit the Lucas 700 series headlamp as fitted to the BSA A10. These are available in 6V 35/35W and 12V 35/35W or 60/55W. They drop right into place without any adapters or modifications required and give much better lighting. They are priced at £7.00 GB, £8.00 Europe or the US carriage paid. I also stock a 12V 23W Quartz Halogen pilot bulb that is ideal for daytime running. Paul Goff carries the bulbs.

cartridge oil filter kits for S/A A10s The A10 kit mounts in the toolbox on ST./ST. spacers and comes with proper oilline ST./ST. hose clips and full step by step fitting instructions. The kit can be easily fitted using ordinary workshop tools in about 45 minutes. The filters are standard car parts readily available. Paul Goff (62 Clare Rd. Prestwood Bucks. HP16 ONU 01494 862841) carries the oil filter kits if you are interested.

fork springs for BSA A10 and Gold Stars Multio-rate fork springs suitable for BSA A10 and Gold Stars are now available. Priced at £40.00GBP inc post UK, £51.00 inc post USA & £62.00 inc post Australia. NORBSA02 at> - Paul Goff - 62 Clare Rd. Prestwood Bucks. HP16 ONU 01494 862841) carries the fork springs if you are interested.

stainless steel carburetor drip shields - these replace the original drip shields which were prone to vibration breakage and rusting. I have successfully obtained a stainless steel drip shield from Mike Partridge at Walridge Motors in Canada

stainless steel fork oil seal holders - Source details to come later

Taper roller steering head bearings - these roller bearings can directly replace the standard cup and cone ball race on BSA A10 steering heads. These bearings provide for improved handling, easier assembly and adjustments, and a long life (up to 250,000 miles). I have obtained these from Mark Dasher with The Classic Cycle Company in Utah. SRM in the UK also carries these bearings (part number SRMTR1 for BSA A&B range swing arm models).

"Superlift" alloy clutch pressure plate - these SRM pressure plates are said to take the "crunch" out of clutches. The no drag, die-cast alloy pressure plate replaces the inferior pressed steel plate. This, together with the radial needle roller lift device, pushes the pressure plate out squarely and true to the mainshaft and stops clutch drag and gear crunch. This enhanced pressure plate will supposedly stay true even if one of the screws loosen or springs loose tension; thereby preventing clutch drag and keeping the clutch cooler around town.

belt drive dynamo This contraption uses a standard toothed V belt and is used without the need to pack grease in the chain area. This item is also easier to adjust and is geared up slightly for if you use the 12 volt conversion.

12 volt conversion Tired of weak headlights at night, buy a 6 to 12 Volt converter. A number of these kits are available such as the JG 12V conversion. JG is distributed by Dave Lindsley in the UK (sorry, I don't have an address). Another person whom britbikers should become familiar with for electrical improvements to their BSA is Bob Kizer who manufactures PODtronics regulators. He also makes AC rectifier-regulators for alternators and solid state voltage regulators for DC dynamos. Bob's POD-6-PE (pos. earth) doesn't require rewiring of the dynamo. The DC regulators are small enough to fit inside a Lucas mechanical box as well as a Miller mechanical box.Side Note: you must maintain RPM's in order to get the "extra" voltage to keep the 12V battery charged which may be difficult at night in stop and go traffic. Some say that it is better to go with a good 6V solid state regulator and use halogen headlight bulbs. Side note: Boyer also makes a 6 Volt steady state voltage regulator for preunit positive earth bikes (available through SRM).

SRM oilfeed and roller bearing conversion This modern improvement will help maintain oil pressure over thousands of miles of abuse. (previously at

sump filter kit with brass magnetic drain plug - This drain plug can be used with a special sump filter kit to extract ferrous metal particles from oil. This drain plug also allows for easier sump draining without the need for gaskets. These filter kits are also available from SRM.

allen type crankshaft oil hole end plugs - End plugs with a hexagonal allen wrench indentation instead of a screw driver slot make life easier by allowing you to get additional torque when removing the end plugs around the sludge trap. This custom type of end plug can be ordered from SRM in the UK (part number SRMSP10)

Pearson clutch - Phil Pearson, a machinist in England, produces a modern day Suzuki 550 clutch that has been machined to work in an A10. Phil Pearson , 34 St Johns Road, Great Yarmouth, Norfolk NR32 9NS,England, Ph / FAX 01493 780055. Phil is also reportedly a source for other improved BSA such as cranks and stainless steel fasteners, float needle improvements, etc.

4 spring Triumph or later model BSA clutch - Installation of this clutch is supposedly a significant improvement over the 6 spring BSA clutch. These later pre-unit clutches are identical between BSA and Triumph except there is BSA mainshaft piece. As a side note, the A10 and Gold Star clutch [4 spring] are the same as Triumph's but the hub adapter for the BSA can be different [depending on which hub adapter] by 3/16 in. in alignment with the engine sprocket and you may have to shim the engine sprocket out 3/16 in. In addition, the clutch shaft in the transmission for the A10 is longer that the main shaft in the GS. [explains why the engine mounting plates on the A10 are off set.] That would cause a huge alignment problem for either bike - is using the wrong transmission and also explains the different length clutch rods. Also, the splined bushing in the cush drive [the part that splines onto the crankshaft] has several different width shoulders between the engine sproket and the bearing spacer that goes on just before the cush drive. This also changes alignment. There are several different spacers listed that can be inserted into this space to help provide alignment. The spacer that goes between the inner primary and the engine case is not listed in earlier parts books, the later parts books do show it. It should be used in all cases. Without the spacer, the oil seal grooves on the inside of the clutch bearly engage the alloy slider in the inner primary case.

(info supplied by George, BSAGoldStar at ).

If any readers have additional information on enhanced or superior replacement parts for these parts, please write me: Daniel Boss