Compression ratio

[pyromaniac]

Hi there. I live in Sweden and the only pumpgas we have is 95,96 and 98 octane. Someone said before that its just as bad as the 87 octane in USA but i doubt it. Anyone KNOW how good our 98 octane is?

What i have been thinking about is if i could raise the compression on my bikes and what effect it will have. How much compression do you think i can have? What ratio do you get with a cosmetic high compression gasket?

 

[Rich Rohrich]

The euro fuel ratings are for RON octane, which puts your 98 octane on par with US 90-93 pump octane. There are lots of things that enter into determining octane requirement for a specific compression ratio. That said it's unlikely that you'll be able to raise the compression ratio and run pump gas without making other changes to the engine.

 

[pyromaniac]

Ok what more do i need to know to determine possible compression ratio? What kind of mods would i have to do?

 

[Rich Rohrich]

I guess I should have more clear. Pump gas and higher compression don't mix in modern two-strokes. If you want to run pump gas forget about raising the compression ratio.