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blk bassani thunder
1,248 Posts
Discussion Starter #1
Does anyone know or what would you suggest as far as upgrading my crank and rods in the full SE build I'm saving for.

So far my list contains by part #'s

16677-05 SE Heads
17056-01 SE Head Gasket
17004-01 SE Head Studs
25740-05 SE Cams
22711-04 SE Pistons
18344-05 SE Valve Springs
18562-02 SE performance tappets
forgot # SE Pro perfect push-rods
38002-04 SE performance clutch

I know I'm leaving some stuff out. But I know they don't make a crank or rods in the SE for the Nightster.

What would anyone suggest!!!! Thanks

39,566 Posts
Are you planning on building a stroker sporty? Longer stroke = lower redline.

39,566 Posts
Sportster and Buell Heads
Aaron Wilson

Screaming Eagle Sportster heads are what we call a "Lightning" head. They
came out in 1996 on Buell S1 Lightning models, and a dual plug version
came on the 1200S as well. They have the same size valves as a regular
1200 head: 1.715" intake & 1.480" exhaust, and the ports are the same. HD
claims 8% better flow from the Screaming Eagle heads. But I've flowed a
lot of heads, and I haven't seen it. Even identical heads vary pretty
significantly from one to the next, and the range of numbers I get from
1200 heads and SE or Lightning heads is pretty much the same.
The big difference between a 1200 head and a Lightning head is the
chamber. Where the 1200 head is a 67cc hemispherical chamber with no
squish band, the Lightning head is a 62cc chamber with a pair of 10 degree
squish bands. Note that these 10 degree squish bands don't do anything for
you with a stock flat top piston. But the smaller volume of the Lightning
chamber bumps the compression ratio up to about 10:1 with flat tops.
That's really where the performance improvement of a Lightning head comes
The problem with Lightning heads, besides the ports and small valves, is
that the extra material they put in the chamber to get the volume down
tends to shroud the valves. The shrouding gets really bad when you start
sticking big valves into the heads. When we do a 1.850" or 1.900" valve in
a Lightning head, we always have to unshroud the valves quite a bit to get
the low lift flow back. And that ends up taking the chamber bigger, often
all the way back to 67cc where the 1200 head is. So then we have to either
cut the hell out of the deck to get back to 62cc, or generally we recut
the squish band to 15 degrees and put the customer into a set of
Thunderstorm pistons, which is a better solution anyway because he gets a
squish band. So essentially, we end up converting the Lightnings to
In 1998, Buell came out with the Thunderstorm head. It has improved ports
as well as larger valves: 1.810" intake and 1.575" exhaust. The chamber is
67cc like the 1200 head, but it has a pair of 15 degree squish bands. So
this chamber doesn't have so much material in it and they're able to put
in big valves without shrouding them. It's a big improvement. If you put
the Thunderstorms over flat tops, you'll have 9:1 compression with no
squish just like you'd have with a 67cc 1200 head. But Buell paired these
heads with a small 15 degree domed piston that gives 10:1 compression. All
in all, it's a much better setup than the SE/Lightning heads. And the
ports have some extra material where the Lightning heads really need it,
so we're able to make a better port out of them. One downside to
Thunderstorm heads on Sportsters though is that they're only available in
black finish, no silver or black w/polished fins (not that some people
don't convert them). Lightning heads have been made in all 3 finishes.
Also, Thunderstorms have 7/16 NC front mounting holes, your Sportster uses
3/8, so you've got to drill the holes in your mount and swap your
hardware, but that's pretty easy.
In 2003, Buell came out with the "XB" head. Same size valves as the
Thunderstorms (1.810/1.575), but the valve stems are 7mm for less weight
and the springs are conical style. They can easily support .550 of lift
right out of the box, where all the older heads were only safe to about
.500. They also have a 62cc bathtub chamber with a pair of flat squish
bands. So now you can get 10:1 with your flat tops and have an effective
squish band and big valves that aren't shrouded, and the best ports
they've ever made (they tend to flow about the same as Thunderstorms but
it's a less turbulent flow). In 2004, they put these heads onto the 1200
Sportsters as well, and they made them black with polished fins (the Buell
XB heads are silver). Putting XB or 04XL1200 heads onto an 86-03 model
isn't too bad, the only real issue is the front mounting bolts (front
head), they moved the right front one inboard by a quarter inch and like
the T-storms, the hardware is 7/16" as used on most Buells. So you've got
to open up the holes in your front mounting bracket and elongate the right
side one. If you go the XB (silver) route, you'll also have to
mill/drill/tap your breather holes, the XB heads have the bosses but
they're not prepared because the XB breathes out the top of the rocker

39,566 Posts

blk bassani thunder
1,248 Posts
Discussion Starter #5
So all in all it's better to go with the buell XB heads instead of the SE heads? Who specializes in these 88 to 90 builds? A harley dealer or who?

So what would you suugest to keep and get rid of out of my list their, or how to approach this since I'm new to all the Harley building.
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