Hartley Enterprises specializes In custom high performance engine kits for sport and recreational use.  2.8 and 3.0 liter V8 engines have been built in the past.  The present focus is on 4 cylinder NA and turbo engine kits and a new V8 is under development!




The BOLT 4 is a 16 valve L4 engine.  It utilizes the Suzuki Hayabusa head and incorporates race car  features such as a high capacity alternator, flywheel with an automotive race clutch, adapter for Hewland and other gearboxes, robust crankshaft, advanced dry sump oiling system and low crankshaft center height .  See BOLT 4 Specs. page for details. 



MAXI V8 UNDER DEVELOPMENT. The MAXI will be the biggest, most powerful motorcycle engine based V8 available anywhere.  

Specs? Dimension? Photos? Stay tuned!










  Hartley Enterprises working on the following projects:

  • New MAXI V8  The design is completed. 2 engines being produced.  One is sold.  Dyno testing late 2017, to be offered for sale 1st quarter, 2018.  (updated 8/2017)
  • 900cc 3 cylinder high efficiency engine The target market is power generation for plug-in automobiles.  Design goal is 80 hp continuous and 50% thermal efficiency using improved adiabatic combustion and unique combustion pressure control.