Engine repair/rebuild

Most motors that pass through the BSD Performance engine room are in for extensive tuning either pre or post-season. Occasionally accident damage has to be sorted and parts sourced prior to any further work and often – especially for one-make race series or Superstock bikes – an engine will require blueprinting to get the very best from it.

All engines, road or race, are stripped and rebuilt in the same way, patiently and methodically. On disassembly every engine part is washed and cleaned with solvent, removing any debris and foreign matter.

For blueprinting the engine is initially stripped down to check everything against spec; this includes weighing, balancing and measuring all the internals. The crank, rods and pistons are individually and collectively weighed and balanced, while the gearbox is shimmed and ‘rumbled,’ giving a much smoother gear change.

Optimizing squish – getting the tolerances between piston and head as close as possible – with improved compression is next. Cams are dialed-in to work without the emissions equipment that is fitted as standard, and redundant for race use. On reassembly crankshafts are measured up with plastigauge to ensure the correct tolerances allowing for oil clearance and application; race engines run ‘looser’ for reduced friction. Cylinder bores – including Nikasil liners – are honed to a perfect ‘cross-hatch’ finish for good compression.

Once we’re happy with the internals and cases they all go through a second, high temperature liquid washing process and all oilways are blown through with high-pressure air. As the engine slowly goes back together two specific lubes are used; a molybdenum sulphide anti-scuffing paste and Silkolene Assembly Lube coat the crankshaft journals and bearings, protecting them on initial start up before being absorbed in to the oil. Trebond, an expensive Japanese jointing compound, is used for gasket surfaces and all gaskets are genuine OE or composite race-only items.

We use and recommend Silkolene and it’s our oil of choice for many reasons; we have a long working relationship with the company and have found, over time, that their products perform consistently well in terms of wear rate and protection. All our rebuilt engines are filled with either Pro4 or Comp4 depending on use, refitted to the chassis and in most instances completely run-in on our dyno under acceleration and deceleration load, ready for use.