Just as an FYI, this is why I would rather buy an early model Rocket with a different shade of output shaft cover indicating there was corrective surgery and a potential that the update/upgrade has been installed to bring the 2004 through early 2007 motors up to 2007 standards.
This is based on my data and not from Triumph:
If it has very low miles (say <10,000 miles) the odds are 1 in 11 that the bearings could be on backwards. This is where there
may be oil leakage around the shaft boot as shown below but no grinding noises. Most were corrected under warranty.
If it has low mileage (say 10-25,000 miles) the odds are slightly better. In these cases maybe the oil leak wasn't spotted earlier.
Noises and/or vibrations start to occur in the lower left side of the engine and need to be addressed ASAP. Unfortunately many bikes were no longer under warranty.
There are a surprising number of 15 year old Rockets with less than 25,000 miles (<1,666 miles/year) and I know of 3 already this year in need of the bearing correction. Triumph will not help you even though this was a known factory assembly defect.
Above that mileage the odds are much lower (but not zero) that the torsion damper assembly bearings were put on incorrectly. I know one made it to 40K and one to 80K.
You could just fix the bearing or put in the update/upgrade kit if you can find one. The kit is now US$1,200 and labor will be
at least $1,000 at a shop.
This is what YOU DON'T WANT TO SEE when going to look at an early model year Rocket unless you're willing to take on a major project:
Unfortunately, the leak may not occur in all cases or may have stopped (or an unscrupulous seller has hidden it).