Click on the Image Above for a Slide Show of 1275 Available Colors and Fin Styles HAMMER PERFORMANCE RAISES THE BAR AGAIN!
We're pleased to announce the world's first and only BOLT-ON 1275 KITS for the XL platform!
These kits stand alone as the biggest XL engine kit available that can be installed in an afternoon without case boring and without removing your engine from the frame.
Each kit comes standard with the best components on the market: The 1275 cylinder is based heavily on our legendary 1250 kit, with one key difference: the liner is made of special 120,000 psi tensile strength steel.
This extra strong liner material enables a thinner spigot, which in turn enables the bigger bore.
The working area of the cylinder remains at a full four inches outside diameter, maintaining the thick, strong cylinder wall. One of the great things about the 1275 kit is that it delivers more power over the entire rpm range, unlike a lot of mods that tend to rob from one area to give more somewhere else.
As a result, this cylinder delivers superb ring seal in even the most highly stressed, demanding applications, enabling more power! Take a look at these actual results: Here's what a 1275 brings to a late model EFI 1200This motor has stock EFI 1200 heads, stock W cams, and stage 1 mods (air cleaner, exhaust, tuner) In blue is a flat top 1275 kit In red is a flat top 1250 kit In green is the stock 1200 cylinders and pistons Click here for more information on converting your 1200 Here's what a 1275 brings to a late model EFI 883This motor has stock EFI 883 heads and stock W cams In blue is a 1275 kit with reverse dome conversion pistons and stage 1 mods (air cleaner, exhaust, tuner) In red is a 1250 kit with reverse dome conversion pistons and the same stage 1 mods (air cleaner, exhaust, tuner) In green is the stock XL883 Click here for more information on converting your 883 Actual Result From our 2007 XL883/1275 Sportster With the 120 Horsepower Package This shows what's possible with the 1275 kit in combination with head work, cams, and other components As with the 1250 kit, the 1275 kit is available in either the 1986-2003 small fin or 2004 big fin style: You can see what a massive difference in fin sizes this represents!
HD introduced big fins in 2004 when the cylinder pressure in 1200's was raised dramatically.
The larger fins were part of a coordinated plan to improve the cooling of the motor to handle the additional heat, along with oil squirters under the pistons and MAP based ignition.
Don't compromise the cooling or appearance of your motor - use big fin cylinders on 2004 bikes! Big fin cylinders will also fit on 1986-2003 bikes.
We offer the 86-03 small fin style as well, so that owners of that year range can maintain the proper appearance.
Also notice the CNC highlighted fins in the above photo! All black highlighted HAMMER 1275 cylinders, big fin or small fin, receive the CNC machined fin edge treatment.