CJS Customer Projects

998- 155bhp tune

Phill was a previous Japanese bike owner.  He decided to purchase a Ducati 998 which he liked very much but was dissatisfied with the straight line performance compared to his old gsxr.

Phill had his heart set on getting 150 hp from the 998s with big midrange power. After a long chat at the CJS workshop Chris said he could make this possible.

In order to get this sort of power from a 998 and keep the engine reliable the engine had to be blueprinted using a balanced crankshaft/flywheel assembly with pankil conrods and pistol 13.1 pistons. The crankshaft balance is critical for high rpm smoothness and prolongs engine life.

As usual the bottom end was shimmed to spec assembled with squish set to the optimum but safe distance for 11.000rpm use.

In standard trim the cylinder heads are only good for 139hp with a big exhaust .  To reach 150hp it needed serious revision especially to the short side radius, throat size and valve angles. Chris re-worked the ports on the flow bench to make the desired shape and installed 2mm larger flat nail intake valves using the PEG multi angle seat cutter.  Chris knew Phil was  a member of the DSC and many people would get to hear about the project so he  ran several more than usual flow tests to establish a better valve and seat combination for more airflow and power . 

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The new port shape with colsibro race guides.

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New combustion chamber shape with oversize inlet valves.

The new re-worked heads were shimmed using the standard cams which were degree'd to a tried and tested spec to boost the midrange power.

After the engine was installed  a full 57mm Leovince exhaust system was added along with a powercommander 3.

DYNO CHART click image to enlarge

People ask how reliable a 155hp tune would be.  This engine  is now stronger and more reliable then Ducati ever  made it . The peak power is produced at a lower rpm than originally intended prolonging service, valve and rocker  life !!

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