CB750F, CB900F, and CB1100

RPE Racing has designed several big bore engines for the Honda DOHC engines through several years of experience in motorcycle tuning for either road and race engines and thorough research and development.

You can send us your complete engine or you can leave your bike with us which will then be dyno tested and tuned to get the most out of the modifications:

CB750F Boldor:

  • 835cc big bore Engine – bore and hone of the original cylinders.
  • 1150cc re-sleeving of the barrel with cast sleeves, bored out crank cases, custom H beam conrods, Hypoeutectic or forged pistons and head gasket to suit. This also available in kit form see products.

CB900F Boldor:

  • 998cc big bore Engine – bore and hone of the original cylinders.
  • 1100cc – re-sleeving of the barrel with either cast sleeves, bored out crank cases + upgrade with our custom heavy duty conrods.
  • 1225cc – re-sleeve of the barrel with cast sleeves, bore out crankcases + upgrade with our custom stronger conrods.
  • 1300cc – re-sleeving of the barrel with cast sleeves, bored out crank cases, custom H beam conrods, Hypoeutectic or forged pistons and head gasket to suit. This also available in kit form see products.

CB1100 Boldor:

  • 1198cc big bore Engine – bore and hone of the original cylinders.
  • 1300cc – re-sleeving of the barrel with cast sleeves, bored out crank cases, custom H beam conrods, Hypoeutectic or forged pistons and head gasket to suit. This also available in kit form see products.

As usual some clients aren’t satisfied with a simple increase in displacement and we RPE also feel that the old twincam engine has a lot more potential to be unleashed so we offer an array of in-house modifications available which include:

  • hotter camshafts
  • head porting to improve flow and volumetric efficiency after a big bore Engine
  • bigger valves to help the bigger engine breathe
  • heavier rated valve springs for more rpm
  • race spec valve guides to avoid seizure at higher rpms
  • standard carburetors can be replaced by bigger, better flowing units (several options)
  • performance 4 into 1 exhausts or 4-2-1 or 4-2
  • ignition timing revised to suit all modifications
  • crankshaft machining to knife edge with lightening and balancing
  • fuel injection
  • engines tested and ran on our dyno

All of these upgrades have the rest of your engine reconditioned.