Harley-Davidson TC96 Engine
In the 2007 model year, Harley-Davidson
introduced it's improved version of their twin cam 88 (TC88) engine. The
engine fixes many issues that the MoCo publicly stated weren't problems on
the TC88 but the fact that these oft complained about maladies were
addressed indicates otherwise.
A few RMH regulars have already
put thousands of miles on these engines. Many say it's smoother running,
smoother shifting and delivers power far smoother than it's predecessor.
Some of the more important changes:
- 1584cc or 96ci engine: new cams, longer
stroke for more torque/mid-range power,
- 6 gear transmission:
makes 80 MPH long distance rides a quieter, smoother affair with 11%
lower RPM at highway speeds. (the 6 speed tranny was added to the Dyna
line in '06)
- Automatic hydraulic cam
chain tensioner: while some TC88 tensioners went 60k+ without a
problem, many disintegrated in far less miles stranding plenty of
disgruntled riders and requiring complete tear-downs. The MoCo said it wasn't a defect. The TC96 fixes the
- Exhaust system O2
sensors: lower emissions allow Harley's to avoid using catalytic
converters by super fine tuning the fuel/air mixture for an efficient
exhaust. The tone of the stock exhaust is lower with more rumble than
- 25 deg. angle fuel
injectors: my '06 TC88 came with 8 deg injectors which idled poorly
and stalled. The MoCo changed 'em out for the 25 deg. injectors that are
now standard in the TC96 and it idles fine now. Another non-defect
- Starter bolted directly
to primary housing: eliminates the need for a jackshaft. Less moving
parts to fail.
- Screw-in oil dipsticks:
previous models had a rubber cork which had a history of popping out
during undue pressure on some engines.
- Internal oil passages:
No more external oil lines, looks better, less possibilities of related
leaks (not that this was an issue with TC88's).
- Lighter pistons and
rods: reduces vibration (or so the MoCo says).
- Recommended fluid change
intervals extended: primary=10k, Tranny=20k
Some issues that have come up
regarding the TC96:
- Noisy 5th gear reported by
some is the result of using traditional a spur-cut gear for 5th rather
than the helical-cut gears used on 2, 3, 4 & 6th.
- Excessive heat at low
speeds (seems the TC88 suffered the same issues, particularly in the 1st
- Automatic primary chain
tensioner: H-D removed the primary inspection port making it
necessary to remove the entire primary cover to take a peek. This also
removed the easy option for pouring fluid in as well.
- Starter has a spring
loaded compensator between the driveline and the engine which results in
a "starter knock" or thunk when the springs bottom at startup. This, of
course, H-D sez is normal.
T.L. Mitchell writes:
"H-D has been touting an
ECM software upgrades enhance "driveability" on early pre-November '07
models. Nobody seems to know what this is all about but everyone with an
early OEM or Stage ECM configuration not only got the initial
notification, they're getting reminders if they haven't had it done..
Seems the MoCo really wants folks to get the new software although no one
that's had it done can see any difference in performance or operation.
Which makes one wonder what's wrong with the original setup that's making
the MoCo so eager to have it
"upgraded"? You can bet they're trying to avoid something that might cost
them money in the long run, IMO."