Sportster Evo Package, Improving your Harley Davidson performance

The Street Port

This is an effective way to eliminate the limitations of the stock head castings. This service is suited to any of the following Andrews cams: V/N2, N3, V/N4, V/N6 and the V/N8. As with the Twin Cam these heads are blasted and inspected before receiving the multi angle intake and exhaust valve job with bowl blending. The heads are then milled to set compression to match the chosen cam profile.

£300 All production years

883 - 1275 Head Upgrade

When considering any performance project, the available displacement is the foundation of the build. It is this combined with the cylinder head flow characteristics that governs the potential power capable of being developed. My 883-1275 Sportster conversions are proving very popular and it is with this upgrade in mind that this cylinder head conversion has been designed. The stock 883 heads have tiny ports and valves that barely flow enough to support an 883 engine and this weakness is further compounded by the addition of an extra 44% increase in cylinder volume. The only way to bring the 883 heads up to the standard required to support the extra gas flow is to fit larger valves, profile the ports and modify the combustion chamber. The stock valves are replaced with high flow stainless steel 1.72 inch and 1.48 inch valves and the ports are then contoured to match. The seats are given precision multi angle and radius profiles to match the larger valves and the bowls and short side radii are blended into the new seat dimension to ensure maximum flow throughout the valve lift range. A 1275cc motor cannot develop to it’s full potential when equipped with heads designed for an 883cc motor.

1991 - present heads £450