Cylinder Heads
High Performance Factory Heads are Available from HAMMER PERFORMANCE!
HD has offered a lot of heads for XL & Buell models over the years, some good and some not-so-good. If you're looking to upgrade to the best ones,
Hammer Performance can set you up. We offer factory performance heads either as bare castings with stock seats and guides (which make a great basis for your
Smash or Sledge porting service), or fully assembled and ready to bolt-on.
Buell Thunderstorm Heads - No Longer Available
As of July 2013, we're having trouble sourcing new Thunderstorm heads. The last bikes that had them rolled off the assembly line 11 years ago, so this is no
big surprise. We'll leave the information below for reference purposes, but we can no longer supply new Thunderstorm heads
Buell Thunderstorm heads were the first real performance head for XL's offered by the motor company. They came out in 1998 on Buell S1W and S3 models,
and instantly became enormously popular as an upgrade for XL's and other Buells.
The improvements over the previous XL heads came in the form of much larger valves, improved ports, and an improved chamber. Valve sizes were increased from
the earlier 1.715" intake & 1.480" exhaust all the way up to 1.810" intake & 1.575" exhaust. This alone results in dramatically better flow. But the ports were
improved as well, with a higher floor and a more gradual radius in the roof through the bowl area. Finally, the chamber was improved to add a 15 degree squish
band while not shrouding the valves terribly, and the heads were paired with an all new matching piston. Squish band effectiveness is limited, however, by
the cast-in squish shelf, which is uneven and not very accurate. Hammer Performance can machine this area for a precise and effective squish band.
Retrofitting these heads to 91-03 Sportster models is very straightforward, as they are almost a bolt-on. The only issue is that the front head's front mount
bolts are 7/16-14 thread, instead of the 3/8-16 as found on 91-03 Sportsters. Some drilling of your front motor mount bracket will likely be necessary, and you'll
need to fit a short stud onto the left side (spark plug side) or use a very short bolt.
Retrofitting these heads to 86-90 Sportster models is not recommended, however, plenty of people have done it. The main issue is the spacing of the pushrod
holes. Four-speeds have slightly different geometry because the tappets are offset from the cams slightly. When you put
five speed heads onto a four speed,
you risk causing a pushrod rub problem where the pushrods pass through the heads. The same bolt hole size issue described above also exists
when retrofitting these to four-speeds.
Retrofitting these heads to 04-up Sportster models is recommended even less. First off, if your 04-up Sportster is a 1200, you already have better
heads than these, so swapping them would be a downgrade. But even if you're looking for something better than your 883 heads, Thunderstorms are generally not
the best choice for an 04-Up. Thunderstorm heads have smaller fins than the 04-Up Sportster head & cylinder fins, and they may look funny sitting over
the top of your late model cylinders. Also, the front head's right front mount hole (pushrod side) sits 1/4" more outboard on a Thunderstorm head than on
a late model XL head, so a mount modification would be needed. It's not impossible to put these on a late model XL, but most people opt for the Buell XB
or late model XL1200 heads instead.
Thunderstorm heads are available in a straight black finish only. The fins can be highlighted manually but this seldom comes out looking as good
as a factory highlighted fin. If you're looking for highlighted fins, we recommend going with some 2004-Up XL1200 heads as listed below. If you're looking
for silver, you can either paint a set of Thunderstorms, or go with a set of XB heads listed below. You could strip and powder coat a set of
Thunderstorms, but by the time you got done, you'd be into them about as much as a set of XB heads.
Thunderstorm heads are available from HD either bare or fully assembled. However, as of their latest price increases, they're charging the same amount
either way. Therefore we are only offering them in assembled form.
Despite the introduction of the Buell XB and 2004-Up XL1200 heads, Thunderstorms remain popular.
The bikes that Thunderstorms came on as original equipment are long out of production, though, in fact Buell doesn't even
exist anymore, so who knows how long these heads will be available. If you want a set, get them while you can.
Buell XB Heads and 2004-2006 XL1200 Heads - No Longer Available
As of Spring 2022, Buell XB heads and 2004-2006 XL1200 heads are no longer available from HD. We'll leave the information below for reference purposes, but
we can no longer supply these heads new. But if you need modern heads for your carbureted application, see the 16500164 SE heads described below.
The Buell XB heads came out in 2003, and an XL version of these heads came on all 2004-2006 XL1200 models. These heads feature improved ports over any of the previous
factory heads, with large 1.810" intake and 1.575" exhaust valves featuring lightweight 7mm stems and a beehive spring pack that can handle up to roughly .580 lift
(previous XL heads were only safe to .500 lift). Although they flow about the same as the Thunderstorm heads, they do it with a smaller port and the flow is
less turbulent, both of which result in more power. In our testing, comparing stock to stock, these heads are worth 4-5 extra horsepower over Thunderstorm heads,
in situations where the heads are the thing limiting the power. Stock Thunderstorm heads start becoming a big bottleneck at around 90hp and these heads
in stock form start becoming a bottleneck at closer to 95hp.
Another improvement in these heads over the Thunderstorms is the compact 62cc bathtub chamber. Although the factory claims 60cc, in reality most measure out to 62cc,
not unlike Twin Cam heads which are spec'ed at 85cc but generally closer to 87cc. The bathtub chamber shape gives a nice, even squish area when used over flat top
pistons, with a large squish band surface area to promote good mixing, which gives better detonation resistance and more efficiency.
Over flat top 1200 pistons, these heads give a 9.7:1 compression ratio, over flat top 1250 pistons they give a 10:1 compression ratio, and over flat top 1275 pistons
they give a 10.25:1 compression ratio. We also offer 1275 pistons with a small dome that will get you 10.5:1 under these heads.
These chambers also give us plenty of material for machining angled squish bands, which improves performance even more by reducing the shelf the air must flow around when entering and exiting
the cylinder, as well as by directing the fuel coming out of the squish band directly at the flame front without being obstructed by the dome.
Hammer Performance offers both 15 and 30 degree angle dome Sledge Hammer forged pistons in our 1275 kits and can CNC machine the heads to match. Virtually all of our performance
packages use 30 degree pistons with matching machine work.
And yet another nice improvement in these heads is the larger cylinder fins. These improve cooling, and when combined with big fin cylinders,
they give the motor a bigger, more filled-out look than the original heads and cylinders on 1991-2003 models. Retrofitting these heads to 1991-2003 models
easy to do and common. Basically all you need is the front adapter mount to attach the front head to the steering neck area, because all big fin heads
have that bolt hole relocated inboard a tad and use larger 7/16-14 bolts instead of the smaller 3/8-16 bolts found on older bikes. Also, XB heads
need their breather bolts machined, drilled, and tapped (a service we provide). And finally, these heads are all 3.670" in height, which is .020"
shorter than original 1991-2003 heads. This is generally not enough to get you in trouble on pushrod length, but check it during assembly anyway.
All XB heads can be used with a standard-width carburetor manifold. However, be aware that in 2007, all XB heads started coming with the
wider intake flange pattern. So if you get a set of those, also get the wider flanges. This is a nice improvement that gives better access to
the bolts.
Screamin Eagle Carb Type Heads (16500164)
Can Also be Used on Buell Carb and DDFI Applications
As of November 2024, the SE 16500164 heads are no longer available. We are leaving the information up for your reference, but we cannot accept any orders.
Please consider using the EFI versions in combination with one of our special adapter intake manifolds that allows the use of a carburetor with EFI heads.
If you're looking for a modern set of heads for your carbureted (or Buell DDFI) application, and you've got a goal of no more than about 100 horsepower, you should consider a set of the 16500164 Screamin Eagle heads.
This is the only remaining carbuetor compatible heads HD still offers. They can be used on applications all the way back to 1991 (note: HD literature
states 1992, but they can also be used on 1991 models if you buy four new spark-plug-side head bolts, offered below).
Like the 2004-2006 XL1200 heads, these are based heavily on the Buell XB heads that debuted in 2003. They have better port castings,
bathtub chambers, big fins, and they come with lightweight 7mm stem 1.810/1.575 valves. The beehive springs they come with are slightly
heavier than the stock XB pieces, and likewise the steel retainers are beefier and stronger as well (but also heavier).
These heads can also be applied to Buell tube frame and XB models. Here are the considerations when applying these heads to Buell models:
- Regardless of whether your Buell is carbureted or injected, you need these 16500164 carbureted version heads, not the EFI versions described below. This is because the Buell DDFI does not use the wider throttle body manifold, the width is the same as a carb manifold.
- The chamber shape on these heads will not work with the original Thunderstorm pistons (Thunderstorm heads & pistons came on all 1998 S3's & S1W's as well as all 1999-2002 Buell tube frame models). So if you're using these to replace Thunderstorm heads, you will need new pistons. Flat tops work well with these heads.
- Tube frame Buells (1995-2002) will also need a new XB type billet motor mount. This is because the front head's mounting bolt sizes and spacing are XB style.
- If your Buell is injected, you will also need the rear head temp sensor machining offered below. This applies to all DDFI Buells, regardless of whether it's an XB or tube frame.
These aren't great heads, don't misunderstand us. The porting job is really crude, with a large stepover and no blending to any
of the places it misses.
You'll see this when you look at the pictures below. The valve sizes are stock and the valve springs are older
technology beehives with steel retainers, as opposed to the modern conical springs with titanium retainers you find with higher end
porting jobs. The valve guides are also standard iron pieces, not the high flow bronze manganese type found on high end heads. The hardware
has a safe lift ceiling of about .585", which is only slightly higher than the hardware found in XB heads and other 2004+ heads.
So this isn't some super-performance set of heads, they're a modest step up from the stock heads.
However, they're not a bad head either, and they're a tremendous bargain at current pricing. The price is lower than a new set of stock
heads (back when you could get them) by the time you outfitted the stock heads with all the hardware they needed, as they were only sold bare.
They certainly fill a need, where a guy has a relatively modest power goal (100ish hp) and needs head castings.
These heads are available in the black highlighted color scheme only.
They use standard width carburetor intake manifolds and the standard width 1991-2006 style manifold flanges (not included).
Being big fin heads, they use the 16689-05 adapter bracket (included) to connect the front head to the steering neck area in a 1991-2003 chassis.
Also required for their installation is a set of 2004+ pushrods, .065" wall, in the -.050" length (available below).
Note that we offer four optional services when you purchase a set of these heads:
- Port Blending: As shown in the pictures, right out of the box the porting job is very crude, with a large stepover and no blending of the cuts.
We offer a hand blending service to correct this and improve the flow. We disassemble the heads, hand blend the ports, and then reassemble the heads with new viton valve guide seals.
- Port Matching to an HSR45/HSR48 Manifold: The ports on these heads have stock size port openings, for compatibility with stock size intake manifolds.
If you use them with one of our HSR45 or HSR48 billet manifolds, you create a step that disrupts the air flow and reduces power.
We offer a port matching service that corrects this condition, allowing you to extract more power from the larger carburetor and manifold.
We disassemble the heads, enlarge the port openings to match the manifold, and then reassemble the heads with new viton valve guide seals.
This service requires the purchase of either an HSR45 or HSR48 billet manifold.
- Dual Spark Plug Machining: This service is primarily offered for owners of 1998-2003 XL1200S models who wish to retain their dual spark plugs.
We disassemble the heads, machine them for a second spark plug through the chimney area (same as found on 98-03 1200S heads), and reassemble the heads with new viton valve guide seals.
Note that there is no performance advantage to dual spark plugs on these heads.
The small, compact chambers with large squish bands provide a very fast and efficient burn, and dual spark plugs will not even show up on the dyno sheet.
- Rear Head Temp Sensor Machining: This service is primarily offered for owners of fuel injected Buell models. It allows the
16500164 heads to be used on 1999-2002 X1's and S3's, as well as 2003-2010 XB models. Includes disassembly, machining, and reassembly with new viton valve guide seals.
You can select these options in the ordering table below.
For higher power builds, we suggest you go with bare EFI castings sold below and have us perform one of our big valve porting services to
them. We can create a better head out of virgin castings than we can out of these SE heads, and the EFI castings are the only new virgin castings still available.
Don't worry if your application is cabureted, because EFI heads can also be used with a carburetor, assuming you get one of our special wider billet intake manifolds for EFI heads.
Which you'll probably be using anyway, in a higher power build.
As you can see, the SE porting job is fairly rough
A large stepover with no blending
We can hand-blend these for a small fee
Contact us for more information
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Much the same on the exhaust port
No blending to the port
Hence the powder coat remnants
Again, contact us if you'd like these improved
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Screamin Eagle EFI Type Heads (16500074 and 16500347)
These are the EFI versions of the Screamin Eagle 16500164 heads described above. The main difference is the manifold mating surfaces are milled down
an additional 1/16" each, to accommodate the EFI throttle body which is 1/8" wider than a standard carb manifold. These heads can be used with
a carburetor, however, if you also get one of our special wider billet intake manifolds for EFI heads
Another difference is the wider intake manifold flange pattern. This improves access to the flange bolts considerably. Since the wider
flanges are not included with the heads, be sure to order a set if you don't already have them, i.e. you're putting these heads onto an older motor.
And yet another difference is that these are available in your choice of either black highlighted (16500347) or straight black (16500074), where the 16500164
carbureted versions are available in black highlighted only.
Since these heads are not marketed for 1991-2003 bikes, the front adapter bracket, that connects the front head to the steering neck
area on 1991-2003 models, is not included with a set of these heads.
Other than those differences, these are the same heads as the 16500164 carbureted versions described above.
They have the same ports, the same hardware, the same big fins, the same bathtub chambers, and require the same shorter pushrods.
Power supporting capability is the same 100ish horsepower.
Note that we offer two optional services when you purchase a set of these heads:
- Port Blending: As shown in the pictures, right out of the box the porting job is very crude, with a large stepover and no blending of the cuts.
We offer a hand blending service to correct this and improve the flow. We disassemble the heads, hand blend the ports, and then reassemble the heads with new viton valve guide seals.
- Port Matching to an HSR45/HSR48 Manifold: The ports on these heads have stock size port openings, for compatibility with stock size intake manifolds.
If you're using them with a carburetor, and you'd like to you use them with one of our HSR45 or HSR48 wide billet manifolds for use with EFI heads, you create a step that disrupts the air flow and reduces power.
We offer a port matching service that corrects this condition, allowing you to extract more power from the larger carburetor and manifold.
We disassemble the heads, enlarge the port openings to match the manifold, and then reassemble the heads with new viton valve guide seals.
This service requires the purchase of either an HSR45 or HSR48 billet manifold.
Be sure to select the wider version of the manifold ("E" suffix) for use with EFI heads.
You can select these options in the ordering table below.
Note that we do not offer a dual-plugging service for EFI heads, because the factory machining for the rear head temp sensor is in the way.
If you're looking for a higher power capability than that, you're better off to start with the virgin 2007-2022 XL1200 head castings offered below.
Your heads will come out much better if we don't try to overlay our porting work on top of theirs.
SE heads come with a beehive spring pack
And a stronger (but heavier) retainer
Suitable for a broad range of streetable cams
up to .585 lift and 7200rpm
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The SE combustion chambers are also machined
But again, not blended
Hence the powder coat remnants
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PLEASE NOTE: We cannot ship stock HD parts outside of the country. If you order any of the follwing HD parts
and your ship address is outside the U.S., we will be forced to cancel and refund your order.
Contact us and we can provide you with other options.
Also note that we cannot apply discounts of any kind to HD parts.
Buell Thunderstorm Heads - Pair
Black |
No Longer Available
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| Buell XB Heads - Pair |
No Longer Available
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2004-2006 Sportster 1200 Heads - Pair
Black with Highlighted Fins |
No Longer Available
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Screamin Eagle Carb Type Heads - $999.95/Pair
Fits 1991-2006 Sportster
Also fits 1995-2010 Buell Tube Frame and XB models (considerations).
Part Number 16500164
Black with Highlighted Fins
Includes 16689-05 front adapter mount to connect front head to steering neck area
on 1991-2003 Sportster models.
Requires shorter pushrods below
1991 applications require new head bolts below |
No Longer Available
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Screamin Eagle EFI Type Heads - $1099.95/Pair
Fits 2007-2022 Sportster
Black with Highlighted Fins
Part Number 16500347
Requires shorter pushrods below
Also fits 1991-2006 (carb) with one of our special wider manifolds |
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Screamin Eagle EFI Type Heads - $1099.95/Pair
Fits 2007-2022 Sportster
Straight Black
Part Number 16500074
Requires shorter pushrods below
Also fits 1991-2006 (carb) with one of our special wider manifolds |
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Port Blending Service - $250.00/Pair
Requires purchase of SE heads above
We disassemble the heads, hand blend the ports to improve flow,
and reassemble with new guide seals. |
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HSR45/48 Port Matching Service - $150.00/Pair
Requires purchase of SE heads above and one of our HSR45 or HSR48 billet manifolds.
We disassemble the heads, enlarge the port openings to match the manifold,
and reassemble with new guide seals. |
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Dual Plug Machining Service - $150.00/Pair
Requires purchase of SE 16500164 heads above
We disassemble the heads, machine them for the second spark plug,
and reassemble with new guide seals.
Offers no performance advantage.
Primarily for 1998-2003 1200S owners who wish to retain their dual plugs. |
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Machine 16500164 SE Rear Head for Temp Sensor - $100.00
Allows 16500164 SE CNC heads above to be used on DDFI Buell models.
See other considerations for using SE CNC heads on Buell models.
Requires purchase of 16500164 SE CNC heads. |
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Stock Sportster EFI 1200 Head Castings - $999.95/Pair
Fits 2007-2022 Sportster
Black with Highlighted Fins
Bare with guides and seats
no valves or springs
ideal for a big valve porting service
Also fits 1991-2006 (carb) with one of our special wider manifolds |
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Stock Sportster EFI 1200 Head Castings - $999.95/Pair
Fits 2007-2022 Sportster
Straight Black
Bare with guides and seats
no valves or springs
ideal for a big valve porting service
Also fits 1991-2006 (carb) with one of our special wider manifolds |
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Intake Manifold Flanges - $17.98/Pair
wide style for 2007-Up Sportster Heads |
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Front Mount Adapter Bracket - $19.99
Part number 16689-05
Connects late model big fin front head to steering neck area on a 1991-2003 chassis |
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Set of Four .050" Shorter Pushrods - $59.50
Required for SE heads above |
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Set of Four Head Bolts, Spark Plug Side - $23.96
Required for Installing SE heads on 1991 Models |
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