What Petrol?

Originally Posted by BillyC

Hang on a1a, I think you've possibly misunderstood the nature of petroleum.

The lower the octane number, the more likely you are to get premature detonation.

Low octane fuels, such as cheap motor-gas require less energy to detonate, and may do so in a hot high-compression engine, such as a motorbike. To avoid this pre-ignition, you should up the octane rating of your fuel.

Higher octane fuel requires more energy to ignite, and can withstand higher pressures and temperatures before detonation - this ensures that detonation occurs only when the spark plug fires.

If you want to look after your SV, with it's compression ratio of 11.5:1 - then you should be trying to get a fuel with Octane levels in the 90's, rather than the low compression US fuels that most American cars are designed to run on.

Just a friendly word of advice.

Hi BillyC,
I appreciate your response about petrol octane. One should always use the lowest octane that does not cause your engine to ping/knock under hard acceleration. Otherwise you are just wasting your hard earned money. Lower octane fuel burns faster and more completely than higher octane fuel. For this reason if your engine pings/knocks using lower octane you need to use a slower burning higher octane fuel. I'm not going to get into the Mon & Ron methods of grading the fuel. But the principle is still the same, the lower the octane the faster the burn. The higher the octane the slower the burn.
My Intruder VS1400 has 9.3:1 compression, has Vance & Hines pipes and DynoJet kit and pings like hell on the lower/faster burning octane. That is why I use the higher/slower burning fuel for that engine. Both owners manuals state to use a minimum of 87 octane using the RON octane rating.
For my SV650 which is 11.5:1 compression and in stock condition. I use the lower/faster burning octane fuel. Because I do not have any engine ping/knocking associated with hard acceleration or higher engine speeds.
Ride safe & often, Richard