Is it ok to use car motor oil in a bike with a wet clutch?

When I'm at the local Kragen, the valvoline 10w40 4-stroke motorcycle oil I'm using is 2.99 a quart. A few bottles over is Castrol GTX 10w40 for cars, and that's only 0.88 a quart. The difference is noticeable and could have very well paid for a quick stop mickey d's. I searched around and people seem to have mixed feelings on the subject. What do you guys think?

 

Just spend the extra money on motorcycle oil.

 

ABSOLUTELY!!!

 

Um guys, if the API and SAE match manufacturers specs then its fine. All the big names will hold up well enough so go w/ what you please. I'm generalizing but most "motorcycle" oil produced by big names are just another marketing name for the same formula w/ at most a different amount of additives. Probably more detergent agents due to the high revving nature. Thermal breakdown and such would be the same as the standard base formula. This is for 4 stroke only of course. All that said, I'd prefer valvoline over castrol but at that price I might not. Then again you should be able to get valvoline 10w40 for a little less than $2 a quart. Try shopping elsewhere than kragen

 

i always use the manufactures sugested oil like honda gn4 20w 50 for a honda cbr900rr. oil does not cost that much so why not by the right stuff.

 

If you change it regularly, I think regular automobile motor oil will suffice.

 

Only a few car oils are suitable, those with no friction additives. If it has Moly in it, it is not suitable for a bike and will, down the road, cause premature clutch slippage/failure (not if you have a Duck though!). Synthetic with no additive is fine.

Basically repeating what is known in the MC community.


[Modified by Dropping_By, 11:33 PM 10/15/2002]

 

Good point, wet clutch systems aremore particular.

 

What do the friction additives do for the automobile motors? i.e. why do they add them?

 

"What do the friction additives do for the automobile motors? i.e. why do they add them?"

I have no idea what they do in a car, but in a bike with a wet clutch the oil is used by both the clutch and the engine.

 

and apparently some of the additives are 'friction modifiers' that coat the clutch and lower the coeffecient of friction to a point where the clutch will slip even when fully engaged.

 

I use mobil 1 car oil and have for the past 10 years with no ill effect.. and it is a lot cheaper then mobil 1 motorcycle oil, just don't buy cheap oil and you shouldn't have any problems...

 

busa1300, I was wondering what weight and was it synthetic? Thanks

 

ive tried a couple of different oils, and some seem to not match my bike. for sure, my bike hated castrol (shift misses), but once i changed it to penzoil, it loved it. soo much smoother. thats for engine oil

for 2-stroke oil i use Honda GR2 or Castrol 2TS or something like that.
GR2 seems to be the best for all bikes even on a kawasaki and yamaha.

 

mobil 1 is synthetic as far as what weight I use 10W-30 (most of the time) or 10W-40. Synthetic oil keeps it viscosity a lot longer exspecially in the High reving motor in motorcycles. Standard dino oil looses it viscosity farly quick in a motorcycle. There is little differnce between the Mobil 1 car oil and the Mobil motorcycle oil other then the price. Some people argue this but I have seen indepandant sudies involving both and many other oils. Mobil 1 car and motorcycle oils finished within 10 points of each other on the scale used at around 500 and 512 . So the 10 points dont mean that much at least not worth 4 to 5 dollars a quart more.