Hammer Performance - for All Your Harley Davidson XL Sportster and Big Twin Performance Needs
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For Sportster & Buell

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General XL & Buell Crank Information

For 1991-up Sportsters and Buells

  1. Why Do Harleys Vibrate So Much? There's a physics reason behind it. With pure rotating weight only (absent any reciprocating weight) a flywheel assembly could be balanced perfectly for all rpms, i.e. it wouldn't matter how fast you spin it, it would always be in perfect balance. But connecting rods and pistons contribute reciprocating weight, and worse, the loads imparted onto the crank by reciprocating weight go up as the square of the speed increase, rather than linearly. The classic way to balance when you have reciprocating weight is to design the motor such that the loads from one rod & piston assembly offset the loads from another rod & piston assembly. However, the 45 degree common crankpin and knife & fork rod assembly make this impossible. So sans a counter balancer, we're stuck with achieving proper balance at one rpm only, with vibrations increasing as the rpm is moved further and further away from that point. Therefore, the most effective thing you can do to improve the balance on an HD motor is to minimize reciprocating weight, i.e. run lightweight connecting rods and pistons. Not only will this reduce vibration, but it will also reduce the wear and tear on the lower end, make a failure less likely, and add power. At HAMMER PERFORMANCE, we offer the lightest connecting rods and pistons in the business for exactly this reason.
  2. More Torque from Heavier Flywheels? No! This is bad information that even some professional shops spread around. Torque comes from cylinder pressure and it's mechanical advantage on the crank (both bore and stroke give it mechanical advantage). The flywheel assembly simply stores the energy, it does not produce it. In fact, when you dyno test a bike on an acceleration based dyno like a DynoJet, a bike with heavier flywheels will, all else being equal, show less torque and power than a bike with lighter flywheels! However, because heavier flywheels store more energy, they make it easier to pull away at low throttle and low rpm without stalling, and likewise generally improve very low rpm manners.
  3. 883 or 1200? Through the 1994 model year, HD offered a separate crankshaft assembly for 883's and 1200's, each balanced for the appropriate pistons. However, beginning in 1995, HD reverted to one part number for either model, a situation that remains true today. When buying a replacement 883 assembly for a 91-94, the part number now supersedes to the common assembly. As explained above, the net result of this change is that the ideal rpm for minimum vibrations will be somewhat different between the two engine sizes, due to the difference in reciprocating weight between 883 and 1200 pistons.
  4. Buell or XL? 1995-1996 Buell S2 models used standard XL crankshaft assemblies. However, beginning with the S1 model introduced in 1996, and extending through the 2002 model which was the last year of interchangeable Buell/Sportster cranks, Buells got lighter flywheel assemblies. The lighter flywheel assembly makes the bike rev quicker and will show more power on an acceleration based dynamometer (e.g. DynoJet). The downside is slightly poorer low rpm manners. A lightweight flywheel assembly from a 1996-1999 Buell will go right into a Sportster from 1991-1999. Likewise a lightweight flywheel assembly from a 2000-2002 Buell will go right into a 2000-2003 Sportster. Beginning with the Buell XB model introduced in 2003, there is no more interchangeability between Sportster and Buell cranks. Likewise, the 2004 & newer XL cranks (rubber mounts) do not interchange with earlier XL cranks.
  5. Pressed or Bolted? Beginning in 2000 all factory XL & Buell cranks became press together assemblies, as opposed to the bolt-together versions found on 1991-1999 models. The press together style cranks greatly complicate crank servicing, in fact HD stopped selling service parts for them, they only offer complete assemblies. However, the pressed design does add some rigidity to the whole assembly and they have proven reliable in street performance applications. Fitted with quality connecting rods, trued, balanced, and welded, they've proven suitable for race applications as well. Press-together cranks from 2000-2002 Buells and 2000-2003 Sportsters can be fitted to 91-99 motors with a minor machining operation on the right side case half, which HAMMER PERFORMANCE can provide for you. Bolt together cranks from 1991-1999 models can be fitted to 2000-2002 Buells and 2000-2003 Sportsters with no problem.
  6. What's the Best Crank? Starting in 2008, all Buell cranks got a new 1.5" crankpin. All other XL and Buell cranks came with a 1.25" crankpin. The larger 1.5" piece greatly increases the rigidity of the crank, resisting "spread" which can cause pinion runout and breakage. These cranks can be fitted to 2003-2007 Buell XB models, but not to Sportster models. If you need a 1.5" crankpin crankshaft assembly for a Sportster mill, contact us, it can be done as a custom.


For 1991-up Sportsters and Buells

Need a new crank assembly for your Sportster or Buell? HAMMER PERFORMANCE has you covered! Whether you're looking for a stock replacement assembly, or a custom racing crank, we can help you out.

Complete Crankshaft Assemblies for Sportsters and Buells



Rod Length


91-03 Sportster
95-02 Buell

Note: the installation of a
00-02 Buell or 00-03 Sportster
crankshaft into a 91-99 motor
requires minor machine work
to the right case half.
Contact us for more info

Note 2: The 96-99 Buell crankshaft
assembly has been discontinued




04-up Sportster




03-up Buell XB



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Crank Work

HAMMER PERFORMANCE can handle all your Sportster/Buell crank prep!

XL Sportster Pressed Crankshaft Flywheel Assembly with Carrillo Rods
A pressed crankshaft for a rubber mount XL Sportster with Carrillo rods and welded crankpin

At HAMMER PERFORMANCE, we have extensive experience preparing crankshafts for high performance and racing use. We know what works and what doesn't, and we know all the little tricks to make them as durable as possible. See below for a selection of the services we offer. These prices are for the service work only, parts are additional. See below for our selection of lower end hard parts.

Crankshaft Services for Sportsters & Buells



Service XL Crank
Disassembly, Replace Worn Parts,
Reassemble, True
Balance Optional

Note: pressed together cranks serviced in
partnership with Dark Horse Crank Works


Weld Crank Assembly
Adds Rigidity and Strength


Cryo Treat Crank Assembly
Improves Durability Under Severe Conditions


Resize Rods
For Rods with Out of Round Big Ends


Weight Redistribution
Helps Resist Flywheel Spread in High Rpm Applications
Requires Rebalancing


Connecting Rods

Quality Connecting Rods from Carrillo

High Performance Carrillo Connecting Rods for Harley Davidson XL Sportster and Buell Models

One of the first lower end components you should consider upgrading on your XL or Buell hot street or race motor is the connecting rods. A connecting rod failure is an ugly thing that ultimately costs much more than it costs to just get a good set of rods in the first place.

At HAMMER PERFORMANCE, we've used all of the popular XL connecting rods, and one brand stands out for their superb quality, high strength, and light weight: Carrillo. These rods have endured brutal beatings at the hands of our 200+mph nitro burning Bonneville Sportster. They will easily hold up in your street or race motor.

In addition to being enormously strong, these rods are also very light, lighter even than the stock pieces, which is remarkable considering how much stronger they are. Less reciprocating weight means less vibration, less wear and tear on the lower end, and more power. They're a terrific complement to our ultra light weight Sledge Hammer pistons.

Carrillo rods are made from their proprietary alloy forgings. They're currently only offering XL rods in one size off-the-shelf, a 6.938" length with a 1.25" crankpin. The 6.938" length is .012" longer than stock to give a little tighter squish with typical gaskets.

If you require a different length and/or a different crankpin diameter, give us a call. Carrillo will do customs. Call to discuss your needs and we'll get you a quote.

Carrillo Rods for Sportsters and Buells



Big End I.D.



83-Present XL, 95-07 Buell (except Blast, XB9, 1125)




Crank Style





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Lower End Parts

Bearings and Other Hard Parts for your Sportster/Buell Lower End

Crank bearings and other lower end parts for Harley Davidson XL Sportster and Buell Models

At HAMMER PERFORMANCE, we can supply all of the hard parts it takes to put a lower end together. We build these motors all the time and we almost always have the parts in stock. If you don't see what you need listed, give us a call, chances are we have it on the shelf.

Lower End Hard Parts for Sportsters and Buells



Pinion Shaft Bearing
Note: Select bearing color code based
on table in factory service manual


Sprocket Shaft Bearing Set
Matched set with bearings, races,
shim, and spacer


Sprocket Shaft Bearing Shim
Note: Select shim size for .001 to .005
flywheel end play


Crankpin - JIMS 3-hole 1.25"
This is the best XL crankpin we've found


Crankpin Nuts - JIMS (pair)


Rod Bearing Cages (set)
Aluminum cages hold 17 rollers each
These cages require the use of non-stepped
copper thrust washers below


Rod Bearing Roller Set, 34 rear + 17 front


Big End Thrust Washers (not shown)
Note: be SURE to match the thrust washer
type to the height of the cages


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