|FLO Headworks is happy to announce the release of a complete
new line of totally trick valve spring kits for Harley-Davidson Big
Twins from 1948 on and Sportsters from 1957 on, and all Buell models.
New technology has enabled us to reduce
tolerances in the valve spring manufacturing process to less than one
tenth of one thousandth of an inch, consistently. This improved
tolerance results in a closer interference fit between the inner and
Some aftermarket spring manufacturers
have used excessive interference in their replacement springs, which
makes for unwanted spring characteristics. Others have used
friction-reducing coatings to reduce heat, but this approach adds its
At FLO Headworks, we have reduced the
interference fit down to .0025”, resulting in the best of both worlds—not
too loose and not too tight, just right! These new springs run so cool
that they don’t even need coating.
To make sure every set of our springs
meets our high standards, we have assembled a valve spring testing
device: the Variable RPM Spin Fixture. Originally designed by a
legendary camshaft designer, this gizmo tests valve train components
using a strobe light and can catch the most minute imperfections.
Here are the numbers: Evolution Big Twin,
Evo Sportster 883 and 1200, and Buell valve springs assembled at 1.
812" will have 125 lbs. on the seat, 280 lbs. at .500" lift,
360 lbs. at .680" lift, and coil bind at 1.060".
Shovelhead and Panhead valve springs
assembled at 1.500"will have 135 lbs. on the seat, 315 lbs. at
.500"lift, 350 lbs. at .575"lift, and coilbind at .875".
The valve spring retainers are machined from grade 7075 aluminum alloy.
Stock keepers and lower collars work well.
Ironhead Sportster springs come in two
different sets. The High Lift set assembled at 1.375" will have 125
lbs. on the seat, 310 lbs. at .500" lift, 350 lbs. at .550"
lift and coil bind at .750". The High Performance set assembled at
1.375"will have 100 lbs. on the seat, 230 lbs. at. 450" lift
and coil bind at .875". There is no need to change from the stock
collars and keepers which work very well.
FLO Headworks high performance valve
springs are manufactured from the very highest quality chrome silicon
wire, shot peened, heat treated and heat set. They are inspected during
every step of the process to insure our stringent specifications.
The valve spring retainers are machined
from grade 7075 aluminum alloy. The keepers are machined from grade 4140
chrome moly steel, heat treated and machined at a 30-degree included
angle. The lower spring seats are machined from premium grade 4140
chrome moly steel and heat treated to minimize wear. This valve spring
kit comes complete as pictured.
Our work and products are guaranteed for
one year. For an estimate on your particular application contact us
directly by telephone at 805-481-6300. Or you can