BSA Rocket 3 - Engines

SRM Quality Engine and re-conditioning service.

  • Full engine rebuild
  • Crankshaft grinding
  • Dynamic crankshaft balancing
  • Rebores
  • Helicoils & thread repairs
  • Lead free valve seats
  • Colisbro valve guides
  • Fin repairs
  • Alloy polishing
  • Electronic Ignitions



The standards for engine rebuilds are extremely high - giving you oil-tight and trouble-free motorcycling. All our engines are assembled in a purpose built dust free room with no machine tools present, this ensures the engine components, and there are plenty of them in the triple, do not get contaminated.

Initially your engine is inspected for wear and damage. An estimate is then compiled listing all new parts, engineering work, repairs and a list of options such as exterior cosmetics and other useful modifications, options such as dynamic balancing, lead free conversion, tuning options etc etc. This allows you to tailor the work to your requirements.



The crankshafts are reground accurately, with the correct specification radii. Dynamic balancing of the crankshaft is recommended not only for the circumferential balance but also the balance across the shaft (rocking couple). It’s this method of balancing which produces the smoothest ride.


Accurate and quality cylinder head renovation work. We also strongly recommended to use our Colisbro material valve guides that comprise of a Copper, Nickel, Silicone alloy which resists wear, corrosion, a high tensile strength and can cope with rapid temperature changes. Hardened valve seats fitted for use of unleaded fuel.


All our cylinders are bored to within 0.002” (thou) then put onto our Delapena Honer and honed to an exact size. The use of a modern bring machine eliminates the chances of misalignment with the cylinder and ensures the rebores are vertical & parallel.


The conrod is one of the most stressed components in the engine, it’s failure can totally ruin an engine. With most original rods being over 40 years old, we at SRM would advise that new rods are fitted to each re-conditioned engine. We produce our own high strength billet alloy rods for the BSA Rocket 3 engine.


We would  replace the worn bushes with high quality bushes, often these would have to be to special sizes to accommodate wear in the engine cases.