never use automotive oil it's synthetic u can't use synthetic oil in a semi-synthetic engine

 

Whah?[img]i/expressions/face-icon-small-confused.gif[/img]

No such thing as a semi synthetic engine that I have ever heard of, and automotive oils can be regular fossil oils, semi synthetic oils which mix dino oil and synthetic, and full synthetic man made oils.

Some cars specify synthetic only oil, I've never seen one that recommended semi synthetic oil.

In any case, its the friction modifiers that are in auto oils that cause a wet clutch to slip and thats why you dont want to use them in a wet clutch bike. In something like the crf and trx 450R you can use oil w/ modifiers for the engine (hp4 w/ moly for example) and oil w/o modifiers for the clutch (hp4 w/o moly).

 

Only if never operated below freezing. 20W40 and 20W50 are ok from 32 degF and up. 10W40 is good from about 5 degF and up. 10W30 is good from 5 deg F to 90 degF. 5W is good for below 5 degF.
I used to run 20W50 in my XR600R dirt bike. One Thanksgiving weekend in California it got down to substantially below freezing and I could not get the bike kick started until after the sun came up and warmed up the bike/oil for a couple hours. I now run 15W40 year round and this is OK from about 20 degF and up and I change oil about every 100 miles or each ride which ever is sooner. The oil guidelines are from Honda 400EX and Honda XR650R owners manuals.