Just to stir the snakes...

I cannot see any reason to use a racing oil in a street machine. The racing machine likely has its oil changed for every race, so it will not need much in the way of dispersant additives, or additives to make it cling to engine parts when shut down. It probably does not need much in the way of additives to control corrosion or neutralize combustion byproducts. Cold starting isn't likely an issue, either, so the oil doesn't have to address that. It might be wonderful for sustained high speed and high power, although even in racing the engine doesn't put out maximum power for very long at a time (you have to slow for curves, as a rule). But it isn't likely to be optimized for the street.

For lack of a better term, "street" oil is designed to survive cold starts. It is designed to cling to surfaces after shutdown, so they remain lubricated on start-up. It contains additives designed to neutralize acids produced by combustion by-products. It contains dispersants, designed to keep very small particulates from settling out. And it is designed to last for thousands of miles or many months, not just for one race.

It is your machine, and your money. You won't go far wrong as long as you stay away from "Energy Conserving" choices and change the oil according to the maker's recommendations.

  Theres nothing in my s40 manual that says use diesel oil maybe those Japs don't know about that, Someone should clue Suzuki in about that.

Charon wrote on 09/25/09 at 14:32:24:

  I never saw that oil that says street oil,Where do you get that street oil at,Do they have oil for gravel roads too.

Common sense is sometimes pretty underrated.

I have friends and kin who are so educated they are nearly parylyzed when it comes to making a decision. I also have friends and kin who are so against anything to do with educating themselves that they cost themselves pain and money at every turn. It's a balance. I feel lucky to have grown up with 30w and 50w. We didn't talk about molecules back then; we just used "thick" oil in old motors and "thin" oil in newer motors. I read up a little on oil, ask everyone what they use, watch their performance, and decide. The fact is, engines are built with closer tolerances and better metal. The oil has had to keep up, because they run at higher temps now. In my opinion the most important thing is to use oil that doesn't make your clutch slip, and change it often.    Boofer

The only unique requirements you absolutely need to hit are to avoid the clutch slippage causing energy star additives, get over 10 PPM of ZDDP to keep from tearing up your flat tappet cam lobe junctions (antique valve actuation technology that is still used in the 1980's designed Savage motor) and get you a synthetic oil so if your air cooled motor gets overheated accidentally your oil and your Savage doesn't self destruct.

This mix of stuff is generally found in expensive motorcycle oils (over $10 a quart) or in diesel oils (much less expensive as big diesel engines use 5-10 gallons of oil to make an oil change).

Diesels have very heavy duty requirements as they can go 80,000 to 100,000 miles between oil changes and live with much heavier bearing loads and temperatures than are seen anywhere in a car (or most bikes for that matter).

That's why bike guys like diesel oils, they can exceed the requirements of our bike engines at a relatively lower cost.

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BTW, I am a fan of the first oil on the list of BEST OILS that you discovered independently on your very own.   The cost per oil change for that oil is the lowest of any and the protection provided is arguably as good as anything out there.  

You can pay a lot more, but do you get anything for paying the extra money?

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There is a reason that this stuff has become #1 best oil in motorcycledom and has survived every oil war on every list (and at BOBISTHEOILGUY and their endless professional level oil wars) at the top of everybody's list of best oils.

And yes, it has been subjected to JSO tests repeatedly and passed, so the Jap motorcycle mgfs do "approve" of the use of certain diesel oils in motorcycle engines.

Some honest Honda/Kawasaki/Suzuki/Yamaha dealers even recognize that car oils have moved away from being good motorcycle oils due to the issues with car catalytic converter contamination and will actually recommend and sell diesel oils on their showroom floors.  Mine does, right next to the $14.95 a quart motorcycle oils.

And guess which one he sells?  

The one that protects best against EXTREME temperatures, of course.

Use Shell Rotella T - either dino juice or synthetic and get riding.

+1 i love oil wars as well   tis great

as for 'racing oil', well its not the same stuff that racers use on a track of course. i live near a racing circuit but i dont think ill be asking them what they use  too complex

the 1st time i used castrol oil was in my first bike. i switched from dino and found better performance lower revs on the same roads in the same gear and overall smother running

naturally when i got this bike i was (recently changed) dino out suzuki filter and heaver weight castrol oil in     smoother running from 1st turn of the key