User:A40-3011dS/sandbox

The BSA C25/B25 was an update to the C15 and was as successful in the sense of selling in similar annual quantities to the C15. A frame based on the successful competition versions of the C15/B40 was used. The engine was significantly changed with new crankshaft, barrel and cylinder head. The purpose of the engine modifications seem to have been centred around enabling it to achieve higher revs and greater power output. This was achieved, with some models putting out as much as 25BHP. Unfortunately the changes, as well as including some straightforward flaws (the con-rod was initially weak and BSA soon uprated it) made the engine more demanding in terms of maintenance, less tolerant of abuse (regular oil changes were essential) and the performance available at higher revs was paid for with noise, vibration and more rapid wear.