Amsoil car oil in Pointy?

[Bibio]

Originally Posted by SV650Racer

Car oil is not designed to be used in gearboxes..or with wet clutches.

i'll give you half a point for that

Actually, engine oil isn't designed to be run in gearboxes, except that cars now run what is basically light synthetic motor oil in their gearboxes and differentials.
What gearboxes need is oil that is resistant to shearing, and synthetic oils are good at that.
Engine oil also needs good shear resistance, as well as high lubricity, among other things.
The only problem for wet clutches is the potential that the oil will be too slippery and the clutch will slip instead of hooking up. I've never had that problem. My RC-51, though not powerful by modern liter bike standards, does make 72 ft.lb. of torque, and the clutch has worked fine with Mobile 1, as have all the other bikes I've run with synthetic motor oil designed for cars.

Ive been using some decent car oil that is mercedes benz spec for all their cars (a freind is a merc mechanic so i can get 5l for £15) in my gsxr and had no issues at all.

[embee]

Aha, the old oil debate.

First, use whatever you want, I wouldn't suggest one way or another.

The "official" guidelines and recommendations usually revolve round a couple of issues. Additives capable of causing catalyst deterioration and friction modifiers.

Car oils have developed over the years to reduce the additives which will harm the efficiency of catalysts in exhausts for long term emission compliance, this basically means the extreme pressure wear additives containing phosphorus and metal based compounds (e.g. ZDDP). Engine oils made when the old Mini integral g/box was designed had loads of anti-wear additives. Modern "bike" oils typically have twice the phosphorus content of a similar car oil. Modern car engines are designed to limit contact stresses (usually in valve gear) to what the modern oils will support. Gear teeth contacts need some degree of "extreme pressure" protection, depending on the design loads.

Anything with "energy conserving" or similar on the label is more likely to cause wet clutch issues (not definite, but more likely). In order to demonstrate that an oil is OK with wet clutches a test is carried out, and if it passes the label will say "JASO-MA". That does not necessarily mean that absence of the label means bad, it means not tested. "Bike" oils will have the JASO-MA label.

It's up to you.

embee's exactly right of course, but I recently had my '81 CB900F transmission apart, and after more than 75,000 miles running with automotive oil, lots of hard use including a season of racing and a few track days, there isn't any measurable wear on the transmission parts. It would probably be even better if I'd been running oil with more phosphorous.