Q: What octane should I use in my bike??
A: Start by using the minimum octane requirements stated in your owner's manual. If your engine is knocking using this octane, then go to a slightly higher octane. Using a higher octane than is needed is just a waste of money as higher octane fuels cost more.
Q: How do I know if I need a higher octane?
A: The compression stroke of your engine compresses the air/fuel mixture in the cylinders. This compressed mixture is then ignited by the spark plug. Sometimes the mixture ignites due to the compression before the spark can ignite it. This predetonation creates an engine knock which can be harmful to your engine. Higher octane fuels are designed to for higher compression and later detonation. Use the higher octane fuel if the octane you are currently using is causing an engine knock. (Note: CBR engines were not designed for use with higher octane gasolines. So if your engine is knocking with lower octane fuels, it may be an indication of a mechanical issue with your engine.)
Q: Will higher octanes give me a performance boost?
A: No. This is a big misconception. Higher octane fuels are only needed for higher compression, high-performance engines. CBR engines (though they are higher compression engines than most automobiles) were not designed for use with high octane gasolines.
Q: My manual says to use 86 but the sticker on the bike says to use 91. Which should I use?
A: Actually your bike and your manual are saying the same thing. The manual says to use 86 PON (pump octane number). The bike sticker says to use 91 RON (research octane number). Many people think that 91 RON means the same as "premium" gas at the pump. This is another misconception.
In the US, PON is octane used at the gas pumps (Europe uses RON on the pumps). Generally, RON is 5 numbers above PON. The other number, MON (motor octane number), is generally 5 numbers below PON. PON is the average of the MON and RON. Hence, this is why you see the sticker at the pump that says (R+M)/2.
This FAQ was prepared based on information from the following online resources:
http://www.greennature.com/article347.html
http://www.howstuffworks.com/question90.htm
http://www.chevron.com/prodserv/fuels/gas_qanda/api_octane.shtml
http://api-ep.api.org/industry/index.cfm?objectid=B4B18F4F-9334-11D5-BC6B00B0D0E15BFC&method=display_body&er=1&bitmask=002007006006000000
http://www.btinternet.com/~madmole/Reference/RONMONPON.html
http://en.wikipedia.org/wiki/Octane_rating
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