Twin Cam 96 to 103ci
While there's no doubt that the latest incarnation of Harley's Twin Cam 96 is a potent and more than adequate motor, there are still people that like more power. Not necessarily drag-strip power but more torque when you need it-like trying to pass the minivan that just cut you off. A little extra power comes in handy too if you, your significant other, and luggage are pushing the weight limits of the chassis.
01.
Inside the Screamin' Eagle Stage 2 Big Bore kit are new cylinders, pistons, circlips,
While we were searching for a few more ponies on our '09 FLHX we still wanted to maintain the reliability and warranty. H-D has a variety of Stage 2 big bore kits that increase displacement from 96ci to 103 or even 110ci. Due to our being in California, we were ineligible to go for the 110ci kit as the environmental powers that be frown upon such indiscretions. Luckily, the 103ci stage 2 kit is permissible in the Golden State provided we use the stock mufflers.
At the heart of the big bore kits are new, larger cylinders and pistons. The pistons measure in at 3.875 inches in diameter versus 3.75 inches for the stock 96ci slugs. In addition to the big bore treatment a set of Screamin' Eagle 255 cams and SE air filter and backing plate are included. Although any competent garage mechanic can easily perform the work, the ECM must be remapped by an authorized H-D dealer to adjust the fuel and ignition requirements of the larger motor.
02.
Prior to installation the fuel tank, exhaust, and air cleaner were removed from the b
We motored on down to the H-D Fleet Center in Carson, California, where Todd Canavan performed the engine work while Alan Barsi provided color commentary and supervision.
In about a day we transformed the gentlemanly Street Glide into a bike with a tad more attitude. Follow along as we take you through the basic hop-up.
Conclusions:
While the dyno numbers show an increase in power throughout the entire rpm range, they don't begin to describe the seat of the pants feeling. The motor pulls harder and stronger throughout the rev-band and requires less downshifting to find needed power. Best of all this kit retains the factory warranty on the bike and is 100 percent street legal in all 50 states.
SE 255 Camshaft specs
Lift at Valve Intake/Exhaust(in.)
0.555/0.555
Duration, @ .053,I/E (deg.)
211/235
Parts List
Screamin' Eagle Stage 2 Big Bore Kit
PN: 27557-08; MSRP $899.95
Sources
Dyno Daves
Orange, CA
(714) 282-9000
dyno-daves.com
Harley-Davidson Motor Company
See your local H-D dealer.
Harley-davidson.com
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03.
Both rocker box assemblies were taken off, followed by removal of the rocker assembli
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04.
…removal of the rocker assemblies. All four pushrods were removed.
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05.
The rear head was unbolted. After 15,000 miles on the stock cylinders they still look
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06.
After both heads were off each piston and cylinder were removed.
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07.
Todd then removed the piston circlip to remove the piston from the rod.
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08.
Once all of the top end components were removed, Todd moved on to the cam cover and a