Yes you can. I do in my vtx 1300 retro with 11,000 miles. With the heat generated along with the higher rpms, I believe lighter oils do not provide the best protection The 1300 is designed with large moving engine internals, and looser tolerances like big American cruisers. As long as it's not 30 or 40 degrees outside it is not a problem.
the stock spark plug is the ngk ifr6l11 gapped at 39 to 43
Supposed to be
if using your bike in the summer use sae 20w50 but for starts below 50 degrees use sae 10w40
use full synthetic or you can 10w30 for winters and10w40 or 20w50 for warmer weather's
3 3/4 QUARTS
3 1/2 quarts of 20w50
4 quarts with filter change
20w50
20w50
The owners manual recommends 5w30 or 10w30I would not use 20w50.The owners manual recommends 5w30 or 10w30I would not use 20w50.
20w50 Harley Davidson motor oil If you can't get H-D brand oil, you could use any brand 20w50. Stay away from synthetics. I stuck with H-D 20w50. Good luck!
2 spark plugs per cylinder.