Dome Size

[NitroTate]

I ride around 8500' in the colorado mountains, I have 20 cc domes in my coolhead now, drag pipes, ported and polished, dual K&N setup.

 

If I go to 18 cc domes will I still be able to run pump gas or only race.

 

Let me know if more info is needed.

 

Thanks guys

[dlnoss]

8500', you could probably run 18cc or even 17cc domes with premium pump gas. What compression do you have with the 20's? Is your timing advanced?

[NitroTate]

8500', you could probably run 18cc or even 17cc domes with premium pump gas.  What compression do you have with the 20's?  Is your timing advanced?

320632[/snapback]

 

 

No timing advance and I can't remember exactly what my compression was the last time I checked it and I also forgot to check it before I tore the bike apart.

 

I do know that it was actually pretty high compression but I'm convinced I could do better. I am buying a adjustable timing plate so if I do advance, what size would you recommend? I usually use race gas but not alway as it is obviously expensive.

[BigRed350x]

Start with 4

[dlnoss]

18cc should be okay at that elevation but I would check it when you get it back together and make sure it's not too high for pump.