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Mild Bill (Asshole #27)
StephG (Asshole#108)

Revisions/updates  2007 Keeper of the FAQ's
Schmoe (Asshole #128)

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Harley-Davidson TC96 Engine

In the 2007 model year, Harley-Davidson introduced it's improved version of their twin cam 88 (TC88) engine. The 96ci TC96 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 non-defect.
  • 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 it's predecessor.
  • 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 fixed.
  • 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 1k miles).
  • 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."