Main Motorcycle: '09 T100 EFi
Join Date: Sep 2009
Location: Central Virginia
Other Motorcycle: Monster 796 ABS "Pantah"
Extra Motorcycle: K100RS 16/ABS
I always run 4 qts. Never had any issues of over oiled or excessive venting. The spec is so close to 4 qts I don't think the few or couple ounces extra is going to ever be an issue.
Just my 2 cents.
Same experience with lengthy drain and filter change. That's checking the sight glass with the bike on a lift and 100% vertical, and it's really sensitive to the slightest difference in angle. My USA owner's handbook also says 4.0 US Qts. with filter change..., or 3.8 liters.
Will admit I still add 3+ Qts., run the engine for a minute and let it settle for 5 min. per the handbook instructions for a final reading. Always takes the 4 Qts. though to the upper mark/line on the engine case. Never had an issue, touch wood!
'09 T-100 Forest Green / New England White, TORs, Intiminators & fork tubes raised 15mm, Chrome Ikon 7610 - SP8 Shocks, Custom Sargent Saddle, OEM Chrome Grab Rail, Conti Road Attack 2 EVO's 110/80VR19 & 150/70VR17, 7" Cibie lens and uprated H4 bulb.