NovaCoder wrote:I was told by some Honda petrol guy that modern bikes don't need premium but that doesn't mean you shouldn't use it. I always use premium if it's available otherwise unleaded is fine.
The reason we use Premium is to avoid engines from pinging, ie the fuel to self detonate in the cylinder without spark due to temperature and pressure. The result is that it can damage your valves and the cylinder itself by combusting on the wrong stroke.
By using high octane fuel, they require a higher combustion temperature and thus remove this problem. I think it is very important to run all new bikes on premium as they run very high compressions (in the order of 12:1) and even HIPO Cars dont run that. Heck in cars running 9.5:1 sometimes requires use of premium.
I will add though, that you only need to run 95 octane fuel (ie standard premium) cause unless you have an oxygen sensor, 95 tto 98 wont make that much of a difference.
Also, different fuels attain their octane rating differently. Optimax is high density but the other premiums are lower and hence should work fine with carbie bikes.
Guys, dont risk it. The damage from pinging could cost you more than the extra 5 cents a litre.