So what is the difference between a motorcycle oil and a car oil?

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Sep 22, 2004
New Brunswick
Lack of anti-friction additives? The reason I ask is because I'm going to use some motorcycle oil I bought at Canadian Tire in the transmission of my Accord. I can't remember where I heard or read this, but I recall something saying that manual transmissions don't like anti-friction additives, they need a certain amount of friction to work, and this is the reason I'm going to use the motorcycle oil in the transmission. Honda does say a normal motor oil can be used, but I just don't know. Someone know the answer?
Several things. But first we have to break MC engines into 2 catagories 1) air cooled, 2) high reving.

Air cooled MC engines run hotter than water cooled automotive engines under certain circumstances. Oil temperatures up to 300dF are not uncommon. This invariably involves greater clearances in certain parts of the engine to accomodate the greater temperature range of the engine. These clearances end up wanting heavier weighted oils (like 20W-50).

High reving MC engines operate at RPM levels only F1 cars contemplate (CART is RPM limited in the 12,000 range as is IRL, NASCAR stops just under 10,000). 15,000 RPMs is where peak power is developed. This causes massive amounts of shear and the desire for high HTHS in their oils.

Only a few MC engines have catalitic converters, so phosphorous and zinc are not a harmful agents to MC oils whereas they are to auto oils.

Finally MC engines typically use a wet clutch. Here friction modifiers interact with the clutches ability to hold under high TQ loads.
The bike oil will work perfectly in your Accord's tranny. What brand is it?

And let me guess -- a 10W-40 or less is called out in your transmission, right?

BTDT with an '83 Civic. Car was wonderful running a PCMO 10W-40 in the tranny, but a motorcycle specific oil would have been even better.
It's Canadian Tire's Formula 1 brand. It was only 3 bucks a quart so I bought 3. The manual says I can use a 10w30 or 10w40, and says the 10w40 is the preferred choice. My brother is using a cheap 5w30, Autolab from Canadian Tire, becayse that's what the 'factory service manual' he bought on eBay told him to use. also recommends the 10w40 for the Civic as well, and I think I was successful in convining him to try this motorcycle oil in his transmission.
Aha! I just was reading that factory service manual my brother bought on eBay, and my brother was wrong! 10w-40 is recommended for the Civic transmission too. All along, my brother has been using 5w30 in his transmission because hw swore that is what was recommended in the service manual. I don't know how me misread it, but it clearly says 10w-30 or 10w-40. I was right! *does a little dance*
Sooo, would he have shortened the life of the tranny any by using that 5w30 in his tranny?
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