Napa 15w50, 8,000 mi OCI, Honda ST1100

Not open for further replies.
Mar 2, 2006
Ash, NC
1999 Honda ST1100 Water-cooled V4 Shared engine/trans. oil, wet clutch Comments: Napa 15W50 Synthetic oil SuperTech automotive oil filter MMO as a UCL. This is my first run with Napa The wear metals look good and the TBN held up well for 8,000 miles. The oil did shear down a bit but that doesn't worry me. I filled the bike with Rotella 5W40 this time. Blackstone Labs Test results: Oil Napa Syn 15W50 Filter ST7317 Total Miles 178,868 Miles on oil 8,000 Time on Oil 4 mo Make up oil 0 Aluminum 6 Chromium 0 Iron 13 Copper 5 Lead 2 Tin 0 Moly 9 Nickel 0 Manganese 0 Silver 0 Titanium 0 Potassium 4 Boron 10 Silicon 3 Sodium 91 Calcium 1884 Magnesium 119 Phosphorus 720 Zinc 862 Barium Flashpoint F 415 Fuel <0.5 Antifreeze 0 Water 0 Insoluables 0.1 SUS Visc@210f 73.9 cST Visc@100c 13.98 TBN 4.2
Nice to see a good UOA on NAPA 15w50 synthetic. I used it in the past myself. It's a Valvoline product and at $3.39/qt on sale, why not? Would have liked to see a bit higher zinc content but still nice...
fash is very nice. wears is very nice. insoluables at 0.1 ? really that is pretty awesome. sheared down to a lowmid40wt while you could probably go more miles on it, at what rate does it keep shearing down and potentially make wears go up (if any)? and for 178k on the clock....(xxxx)! that is a good run. steve
Last edited by a moderator:
Originally Posted By: Roadkingnc
I just bought enough of this for 2 changes for my harley. Hope it doesnt shear too much in it.
Depends on how long you're going to leave it in there. Honda ST1100 is not known for being hard on motor oil.
Oh yeah, I did notice my current stock of (3) bottles is rated energy conserving when they weren't in the past. How many 15/20w-50 oils are energy conserving rated? No clutch slipping in the ST1100? RoadKingnc, I'll still use it in my motor but may also blend in some Valvo 20w-50 VR1 to boost up zinc levels. Don't use it in your primary tho....
No clutch slip using it in my ST1100. I've tried a lot of different oils in this bike including 10w30 and 0w30 and never felt a problem. Rick
Originally Posted By: Rick_A
No clutch slip using it in my ST1100. I've tried a lot of different oils in this bike including 10w30 and 0w30 and never felt a problem. Rick
I've been using Mobil 1 10/30 Energy Conserving Mobil 1 since 98 in Mr.RC45 with no clutch slipping due to oil being certified 10% freer flowing than non EC oil... and it's a homologated racer with a tall first gear good for 90mph that's known to incinerate clutch plates... Whats confusing the issue is the fact that all motorcycle wet clutches will reach a point in their life and start to slip... Quote Sport Rider Mark Junge, Vesrah's Racing representative, who has won numerous WERA national championships using Vesrah's clutches. In his years of engine work he has yet to see a slipping clutch that could be pinned on any synthetic motor oil. Junge felt that nearly every time the clutch was marginal or had worn springs, the new oil just revealed a problem that already existed.
Not open for further replies.