ducati race Engine cylinder head & dyno tuning specialist ∑ bristolengland



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To increase the power and torque of your Ducati we need to either increase the airspeed into the engine or both airspeed and volume of flow.  Poorly developed heads result in increasing total flow only. This can sometimes result in a slow engine.

CJS Ducati cylinder heads are tailored to your engine.  Each head is carefully re-worked step by step using a flow bench to find the hidden restriction which are not always visible to the naked eye.  They are matched to there chosen camshaft, operating speed and  intended use.  Example : There would be no point in preparing a head with steep race type valve angles and a larger port volume for a head which is using a cam that only lifts to say 10mm.  The valve head  would never see enough cam lift to use the extra airflow resulting in poor airspeed, a slower bike and disappointment to the customer.  Unfortunately this is a common affair for some companies where all they can offer is a one head fits all application.  However there are many other companies out there who are worthy of a great job and I have listed them in my links page.

Examples of How the Heads are reworked 

The Ducati 996 has a pretty good spread of power and torque already.  To successfully port this head  we can enhance the  engines good character.  We do this by fitting a larger intake valve but keeping the cross section of the port around the same size as the original but shaped a little differently.  The larger valve allows us to move more airflow from the same size port  but  the best part is the air is delivered at a much higher speed  resulting in better power and torque throughout the whole rpm range.  For racing cams that lift a lot higher the ports can be reworked further to make the most of the extra lift available.

The Ducati 748r has the worst of the Ducati ports ever seen.  The throat sizes of each port can vary from casting to casting.  The ports are a  little too small for there rpm range and totally strangled by its terrible floor and inadequate valve seat shape.  We correct the ports and use the peg fm1 to re-cut the seats to a different  profile.  This headwork alone will yield between 7 and 13 plus hp with big gains at the  bottom end as well.

Ducati 998/999 race & high velocity porting

The Ducati 998 and 999 has  ports which are actually to big for there camshafts. They can actually be made smaller with no loss of flow. We do this by welding into the port and re-shaping the venturi. This results in a higher velocity  and much improved, power and torque throughout the whole rev range. The mass airflow is mainly  improved  through  careful seat work  and  valves sizes not through the port itself.

making your cylinder head reliable - please read carefully 

A reliable cylinder head should have freshly cut well defined seat angles being cut concentric to its guide bore enabling good sealing without the contact area being too  thin.  A thin contact area may be great on a race engine thatís stripped every few meetings and it may gain a few extra cubic feet per minutes of airflow on paper but its not good for reliability or your wallet.  At CJS we gain airflow in other more thoughtful ways.

Valve guides are seriously important they must be wear resistant, have good oil retentive properties and have an aero dynamic profile for improved airflow.  CJS designed Colsibro bullet nosed race guides attain this in every way.  These guides are flawless and totally finish off your porting job by making it look crisp and professional.  However gas flowing is not about looks but who wants their expensive Ducati heads back looking like they have been attacked by a knife and fork ?