Hammer Performance - for All Your Harley Davidson XL Sportster and Big Twin Performance Needs
Hammer Performance Horizontal Bar



Dyno Room and Results for Harley Davidson and Buell Performance Products and Services from HAMMER PERFORMANCE


New Harley Davidson and Buell Performance Products from HAMMER PERFORMANCE


Garage Sale Products from HAMMER PERFORMANCE


Harley Davidson and Buell Performance Photo Gallery


Pictures of Harley Davidson and Buell Performance Cylinder Heads


Pictures of Custom Air Hammer Air Cleaners








BIG BORE KITS

For Sportster & Buell

Quick Links:


INTRODUCING BOLT-ON 1275 Kits from HAMMER PERFORMANCE

For 1986-present 883 & 1200cc Sportsters and Buell - From $850

Black Highlighted 2004-Present 1275 Kit for Harley Davidson XL Sportster or Buell
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:


Features and Benefits


First on the list is our innovative new cylinder design!

HAMMER PERFORMANCE bolt-on 1275 cylinder spigot Harley Davidson XL Sportster
The 120,000psi Tensile Strength Steel Liner Enables a Thin Spigot for a Bigger Bore

HAMMER PERFORMANCE bolt-on 1275 cylinder liner Harley Davidson XL Sportster
The Working Area of the Liner Remains Thick to Promote a Straight, Round Bore that Doesn't Distort Under the Heat and Pressure of a Running Engine. This Results in Superb Ring Seal.


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. As a result, this cylinder delivers superb ring seal in even the most highly stressed, demanding applications, enabling more power!.

How much more power? 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. Take a look at these actual results:

Dyno Sheet for Sportster 1200 1250 and 1275
Here's what a 1275 brings to a late model EFI 1200
This 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


Dyno Sheet for Sportster 883 Conversion to 1250 and 1275
Here's what a 1275 brings to a late model EFI 883
This 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


Dyno Sheet for 132 horsepower 1275cc Sportster
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:

Small Fin 1986-2003 1275 Cylinder and Big Fin 2004-present 1275 Cylinder for Harley Davidson XL Sportster or Buell


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!

CNC machining fin edges on HAMMER 1275 kit cylinders for Harley Davidson Sportsters and Buells


We don't sand fin edges! All black highlighted HAMMER 1275 cylinders, big fin or small fin, receive the CNC machined fin edge treatment. If you're going for the black highlighted look, there's no need to settle for the sanded fin edges found on some competing 1250 kits. HAMMER 1275 cylinders match the factory fin highlighting on 1200 models and maintain your engine's beautiful appearance!


For the ultimate in convenience, add our pre-assembly option to your engine kit. We'll thoroughly clean your cylinders, precisely gap your rings, and then pre-lube and assemble the pistons and rings into the cylinders. The ready-to-install assembly will then be shipped to you in a sealed plastic bag to keep it clean and safe. This service makes the installation a breeze, as you simply lower the piston down enough in the bore to expose the wrist pin hole, position it over the connecting rod, insert the wrist pin and circlip, and push the cylinder down into position. No special tools required!

Note: 04-up style large fin cylinders will fit on 86-03 bikes. 86-03 style small fin cylinders will fit on 04-up bikes with some grinding on the lowest fin on the pushrod side.

Tech Tip: Are you converting an 883? Be sure to read our tech article on conversions for lots of good information to make your project a success!

GET THE BEST! GET A 1275 KIT FROM HAMMER PERFORMANCE TODAY!


Hammer Performance 1275 Kits for Sportsters & Buells

Heads

Select Details

86-Present XL883
Note: the pistons in these kits
have valve pocket placement that
works with 883 heads only

Fin Style & Color
Pistons
Specific Year of the Motor

88+ XL1200
86-87 XL1100
88-10 Buell 1200

Fin Style & Color
Pistons
Specific Year of the Motor


Note 1: 30 degree pistons require machine work in the chambers to size and shape them appropriately. HAMMER PERFORMANCE can handle this service for you.


BOLT-ON 1250 Kits from HAMMER PERFORMANCE

For 1986-present 883 & 1200cc Sportsters and Buell - From $750

Black Highlighted 2004-Present 1275 Kit for Harley Davidson XL Sportster or Buell
Click on the Image Above for a Slide Show of 1250 Available Colors and Fin Styles



The legendary HAMMER 1250 Kit is a bolt-on 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:


What Makes HAMMER 1250 Kits the Best?

Several things! Let's start with the Sledge Hammer 1250 cylinders, which feature an extra heavy duty ductile iron liner and aluminum fin construction:

Small Fin 1986-2003 1250 Cylinder and Big Fin 2004+ 1250 Cylinder for Harley Davidson XL Sportster or Buell


Why a thick liner? A thick liner promotes a straight, round bore under the heat and stress of a running motor. This provides superb ring seal. The iron liner material is also rock hard for a long, trouble free life, and the aluminum fins promote excellent heat dissipation. Iron lined aluminum is the proven best cylinder construction for street ridden bikes, without the streaking issues of nikasil or the heat and weight issues of full cast iron construction, and we believe the HAMMER 1250 cylinder is the best iron lined 1250 cylinder on the market. There are thousands and thousands of these cylinders in service, in bikes all over the world, making great power and performing flawlessly. You cannot buy a finer cylinder!

In addition to the superior construction, these are the ONLY 1250 cylinders available in the 2004+ big fin style! See the picture above. Other companies ask you to put the 1986-2003 small fin cylinders onto your 2004+ bike. And yes, they can be made to fit the late model bikes by grinding on the lowest fin. But that's a hack! And on top of that, you'll reduce the cooling capacity of your motor. Big fins came out in 2004 for a reason; cylinder pressures on the 1200 models were raised dramatically starting in 2004. Big fins were part of a coordinated plan to manage the additional heat. Other things that were done were MAP based ignition and oil jets to cool the undersides of the piston domes. Head fin sizes were changed at the same time, and using small fin cylinders causes an appearance mismatch. It's just an all around bad plan. Don't go backwards in cooling capacity or appearance - use SLEDGE HAMMER CYLINDERS from HAMMER PERFORMANCE!

And finally, if you've got the black highlighted look on your bike, there's yet another compelling reason to choose SLEDGE HAMMER cylinders:

Sanded fin edges versus machined fin edges on 1250 cylinders for Harley Davidson Sportsters and Buells


One of our competitors doesn't even offer cylinders with highlighted fins. Another of our competitors just hits them with a sander resulting in the product you see on the left in the above picture. HAMMER PERFORMANCE takes the extra time and trouble to CNC machine the fin edges as shown on the right above. This properly matches the factory black highlighted cylinder heads. We do this for both small fin and big fin cylinders (additional cost).

HAMMER PERFORMANCE Black Highlighted Big Fin 1250 kit for 2004+ Harley Davidson Sportsters and Buells
HAMMER 1250 Kits Offer Superior Appearance and Superior Cooling
Don't Settle for Less!


We'd show our big fin black highlighted cylinders next to the competition's offering, but no one else even offers big fin 1250 cylinders!


These kits give a power increase over the entire rpm range. Unlike most mods that rob from one area to give to another, with a 1250 kit you get an across the board gain. Take a look at these actual results:

Dyno Sheet for Sportster 1200 to 1250 conversion
Here's what a 1250 kit brings to a late model EFI 1200
This motor has stock EFI 1200 heads, stock W cams, and stage 1 mods (air cleaner, exhaust, tuner)
In blue is a flat top 1250 kit
In red is the stock 1200 cylinders and pistons
Click here for more information on converting your 1200


Dyno Sheet for Sportster 883 Conversion to 1250
Here's what a 1250 brings to a late model EFI 883
This motor has stock EFI 883 heads and W cams
In blue is a 1250 kit with reverse dome conversion pistons and stage 1 mods (exhaust, air cleaner, tuner)
In green is the stock XL883
Click here for more information on converting your 883



Lightweight High Performance 1250cc 30 Degree Reverse Dome Forged Piston for Harley Davidsons and Buells We also have the best 1250 pistons on the market! Complementing these great cylinders is a set of our exclusive forged Sledge Hammer pistons. These pistons feature extra large valve pockets for those radical cams, anti-detonation grooves, dual wrist pin oilers, expansion grooves for superior ring seal, and for maximum strength with minimum weight. You cannot find a finer piston for your HD or Buell.


For the ultimate in convenience, add our pre-assembly option to your engine kit. We'll thoroughly clean your cylinders, precisely gap your rings, and then pre-lube and assemble the pistons and rings into the cylinders. The ready-to-install assembly will then be shipped to you in a sealed plastic bag to keep it clean and safe. This service makes the installation a breeze, as you simply lower the piston down enough in the bore to expose the wrist pin hole, position it over the connecting rod, insert the wrist pin and circlip, and push the cylinder down into position. No special tools required!

Note: 04-up style large fin cylinders will fit on 86-03 bikes. 86-03 style small fin cylinders will fit on 04-up bikes with some grinding on the lowest fin on the pushrod side.
Note 2: Going forward, 1250 kits will only be available with either flat top pistons (for use with stock 1200 heads) or reverse dome conversion pistons (for stock 883 heads). Other piston applications have been moved to the 1275 kit. Some closeout 1250 versions are still available, see ordering table below.


Tech Tip: Are you converting an 883? Be sure to read our tech article on conversions for lots of good information to make your project a success!



GET THE BEST! GET A 1250 KIT FROM HAMMER PERFORMANCE TODAY!



Hammer Performance 1250 Kits for Sportsters & Buells

86-Present XL883, 1100, 1200

Fin Style & Color
Pistons
Specific Year of the Motor

1250 & 1275 Kit Options

Depending on the year of your bike, other components are necessary for a successful 1250 or 1275 conversion. Specifically:

  • All 86-03 models should get a new ignition system that provides a timing curve appropriate for the 1250 kit. However, since this year range has adjustable ignition timing, the new ignition is not strictly necessary. Read this FAQ for a more detailed explanation
  • All 04-06 models need a new ignition system, to provide a timing curve that's appropriate for the 1250/1275 kit. This year range has no other method for making a timing adjustment and therefore the module is mandatory.
  • All carbureted models (86-06) need a couple of carb jets, to properly adjust the fuel delivery for the larger displacement
  • All injected models (07-Up) need a flash type tuner to adjust both timing and fueling
  • All 04+ 883 models need a new clutch spring at a minimum, however an extra plate clutch pack is recommended to eliminate a common point of failure in the stock clutch
  • All Sportster models need a colder set of spark plugs than the factory stock 6R12's, to prevent detonation with the higher cylinder pressure that comes with the engine kit. We specify the HD 10R12X Gold plugs in the table below for all of our kits. These were standard equipment in XR1200 models, and they're a high quality plug with a special tip design that resists fouling and gives a long life. And they've shown the best detonation resistance of any plugs we can find.
Although these items may be found elsewhere on the site, we have included them in the table below for convenience. Or, see our Performance Packages below for complete packages with everything you need to achieve your desired power level.


1250 & 1275 Kit Options

Description

Add to Cart

Gap Rings and Pre-Assemble Engine Kit ($50)

Upgrade Head & Base Gasket to Full Top End Gasket Set ($60)
Available for XL and 1995-2002 Buell models only
For Buell XB models, get the top end set on our gaskets page but use the head gaskets that come with the engine kit
For XR models, get the top end set from your dealer, part number 17049-08, but use the XR1200 head gaskets we provide

Application

Ignition System - Recommended for 86-03 models, Required for all 04-06 models
Notes:
Nose cone modules were original in 98-03 and can be fitted to any 86-03
1005S-EX is a plug-and-play nose cone module for 98-03
7-pin modules are plug-and-play for 91-93
8-pin modules are plug-and-play for 94-97
we recommend nose cone modules for 86-90

Type

DynoJet Power Vision EFI Flash Tuner - Required for all 2007+ models
See note below for help in choosing

Version

Wide Band Tuning Kits for Power Vision PV1 & PV2
Note: Wide band sensors use an 18mm thread as found on 2007-2013 models
These kits include weld-on bungs for use with 2014+ models or any exhaust without 18mm bungs

Version

Handlebar Mounting Brackets for Power Vision

Version

Visor for Power Vision PV1 & PV2, Flat Black
Makes the screen easier to see in bright sunlight

$27.77

Clutch Upgrade - Required for all 04+ 883 models

Type

Clutch Spring Compressor Tool
Note: This tool is required to change the clutch spring or clutch pack
High quality tool from Motion Pro
For 1991-present


$70

Primary Gasket
This is a high quality rubber coated steel primary gasket

Application

CV Main Jet - Required for all 88-06 models
Note: most basic conversions will run best with a 185 or 190
Note 2: if you have an 86-87 model with the original carb, please contact us for jets

Select Size

CV Pilot Jet - recommended for all 88-06 models
Note: a 45 is generally the best pilot jet

Select Size

HD 10R12X Gold Spark Plugs - $6.95
(sold each)

Tip: Choose your top end gasket set based on the type of rocker boxes you're using. The head and base gaskets all interchange from 1986-present.
Tip 2: Head gasket thickness is chosen to optimize squish clearance. Read more about squish clearance here. The size your motor will want is a function of a whole bunch of tolerance stack-up, much of which is on parts of your motor that are not part of your engine kit. Therefore it's impossible to predict with 100% certainty which gasket thickness you'll want. However, practical experience has shown that the .030 head gasket/.020 base gasket combination gives a good squish clearance more than 95% of the time. Most customers use .030 gaskets, never check squish clearance, and problems are almost non-existent. So our advice is to get the .030 head gasket kit, and if it proves to be too thin, let us know and we'll get you some .040 gaskets.



NOTE FOR 2007+ (EFI) OWNERS: You'll notice that we offer your choice of either a Dynojet Power Vision PV1B/PV2B or PV3. Here's what you need to know to make that decision.

The PV3 is a lower cost version, with less features and functions, but it's totally capable of tuning a modest power 1250/1275 build (up to about 95hp) and we will provide your base tune. So if you're doing a mild 1250 or 1275 conversion, this is right choice as it'll save you a big pile of cash.

On the other hand, if you're planning a high power build or you believe a high power build is in your future, then the PV1B (2007-2013) or PV2B (2014+) is the right choice. That's because with higher power builds, the tune becomes increasingly more critical, and the PV1B/PV2B both support the Auto Tune Pro and Target Tune wide-band tuning add-on kits. These kits are very helpful in achieving the higher quality tune needed by a build that pushes the limits. We recommend the PV1B/PV2B for builds of 100hp or more.

We have indications from Dynojet that these wide band tuning options may be supported on the PV3 at some point in the future. But until that happens, the above advice is what we recommend.

Whether you go with the PV1B/PV2B or PV3, be SURE to source your base tune from US, and nowhere else. This is critical for the health of your engine kit. The kit installation instructions describe the procedure for getting your base tune from us, just follow that procedure and we'll get you fixed up.

1250 & 1275 Kit Performance Packages


Are you converting an XL883? Be sure to check out our 883 to 1250/1275 Conversion Performance Packages! Each of these packages contains a carefully matched set of components designed to deliver a specific power level in the most cost-effective way possible. These are time tested, proven packages.

Overview of the Packages
The Basic Conversion
The 80+ Horsepower Package
The 90+ Horsepower Package
The 100+ Horsepower Package
The 110+ Horsepower Package
The 120+ Horsepower Package

90 Cubic Inch Kits from HAMMER PERFORMANCE!

For 1986-present Sportsters and Buells

Axtell 90 Cubic Inch Kit for Harley Davidson XL Sportster or Buell with Ductile Iron Cylinders and 30 Degree Reverse Dome Pistons
HAMMER 90ci Kit
Each Kit Includes Cylinders, Pistons, Rings, Wrist Pins, Clips, and Head & Base Gaskets as Pictured
30 Degree Pistons Shown, Other Configurations Available


Hammer Performance is pleased to offer 90 cubic inch kits for all Evolution Sportsters and Buells!

Are you looking for arm stretching, tire shredding torque? Would you like the feeling of lofting the front wheel while rolling on the throttle? If so, a 90 inch kit is what you need!

Be aware however that these are NOT bolt-on kits! The motor will need to come completely apart for case boring. Most customers choose to service the lower ends while the motor is apart. Although most are done with a stock crank and rods, some customers choose to upgrade these components as well. Head work and cams are virtually always a part of a 90 inch build because the big motor NEEDS as much breathing capacity as it can get. It's generally best to contact us for specific matching of your pistons, cams, and head work. These builds are custom by their very nature. They can be done from mild to wild. Yes, these are big projects that will take longer and cost more than you think. But if you want the ultimate in torque and power from your Sportster or Buell, this is how it's done!

What Makes HAMMER 90ci Kits the Best?


Let's start with our own cylinder design, cast from 100Kpsi tensile strength 100-70-03 alloy ductile iron. Why this heavy duty material?
  • High tensile strength ductile iron makes for a straight, round, and stable bore, unaffected by the stresses placed on it by a running motor. That means better ring seal from start-up to shut down, which means MORE POWER.
  • This additional strength is especially important in the 90ci application, because the cylinder wall gets very thin on the pushrod side. Aluminum cylinders flex badly here, resulting in a loss of ring seal. In our experience, only high tensile ductile iron is strong enough to maintain a stable bore with the thin wall in the pushrod area brought on by the 90ci bore (3.875").
  • By eliminating the flex, these cylinders also avoid the all-too-common breakage of the spigots that protrude into the cases, a common failure mode of 88 and 90ci aluminum cylinders.
  • The high strength construction also reinforces the cases tremendously, which are otherwise weakened by the case boring operation. We've broken bored cases using aluminum cylinders at horsepower levels under 130hp, but with ductile iron cylinders we've made over 170hp on fuel motors with no breakage!

In addition to the high strength material, our cylinder design also features the big fin style as found on 2004+ XL Sportsters. These bigger fins help keep your big motor cooler. They still bolt right on to any 1986-present crankcase, no worries there. If your bike is a 1991-2003 model and you have the original style small fin heads, we highly recommend you upgrade to big fin heads (2004+ style) for the improved cooling. It's not hard to put 2004+ heads onto your 1991-2003 model, contact us for more details. However, if you'd like to retain your small fin heads, they will still work with these cylinders. 1991+ heads do not properly fit on 1986-1990 models (4-speeds) due to the off-center tappets and resultant different pushrod angles, so if your bike is a 4-speed you will need to use your original small fin heads.

These cylinders are the stock 4.650" height, so they do not change the engine height at all. There are no issues with manifold or exhaust fit and the engine still fits in the frame just like a stock motor, no frame mods required as is generally the case with a stroker kit. Going bigger bore is really the best way to make your XL motor big, it solves a lot of problems and yet makes huge torque and power.

The pistons in these kits are forged from 2618 alloy and feature a thermal barrier coating on the top. This coating reduces heat transfer into the pistons, to better match the piston's heat expansion characteristics to the cylinder, resulting in a more robust combination.

The pistons also feature a clearance control coating on the skirts. This results in a tight fit into the cylinder initially, and then the coating wears-in to the cylinder wall, resulting in the precise amount of clearance needed, thus improving piston stability and ring seal as well as reducing cold engine piston slap noise common with forged pistons.

The pistons are offered in flat tops, a 15 degree dome, and four different 30 degree dome volumes to perfectly match the head work and cams you choose. Note that head work is required for any of the domed pistons. But it's highly recommended for any 90ci build.

Again, case boring is required for installation: this kit requires the spigot holes to be opened up to 4.005" at a depth of 1.5". HAMMER PERFORMANCE can handle this critical task for you. Boring the cases straight and square to the crank is essential for your success with this kit, don't trust this job to just anyone.

For the ultimate in convenience, add our pre-assembly option. We'll thoroughly clean your cylinders, precisely gap your rings, and then pre-lube and assemble the pistons and rings into the cylinders. The ready-to-install assembly will then be shipped to you in a sealed plastic bag to keep it clean and safe. This service makes the installation a breeze, as you simply lower the piston down enough in the bore to expose the wrist pin hole, position it over the connecting rod, insert the wrist pin and circlip, and push the cylinder down into position. No special ring compressor tool required!

It's very important to order the correct cylinders for your cases from the menu below. The reason for this is the clearance cuts to accommodate the oil squirters. 1986-2003 XL's and 1995-2002 Buells have no oil squirters. 2004-Up XL's have off-center oil squirters. Buell XB models have on-center (but angled) oil squirters. The cylinder spigots are notched for clearance according to the application. Also be aware that the cylinders are different from the front to the rear, unlike the stock cylinders, or the cylinders included in our bolt-on 1250 and 1275 kits.


Hammer Performance 90 Cubic Inch Kits for Sportsters & Buells

Application

Pistons

All Evolution Sportster and Buell
883 and 1200 Models

Application
Pistons

90ci Kit Options

Description

Price

Add to Cart

Gap Rings and Pre-Assemble Engine Kit

$50

Free Web Counter