What size are stock domes?

[PolyKarbon]

Im buying a noss cool head but they dont come with domes. What size are the stock domes? And should I get stock size or a different size? Running Wiseco pistons bored one size up.

[racer]

im thinkin they are maybe 23cc, but dont quote me on that. id get some 20's or 21's if i were you. more compression equals more low-end grunt.

[RNBRAD]

23cc/ml is correct.

[sredish]

23s to 22s are what you'd need for stock compression. You can go with 21s at sea level and stay with pump gas, and probably 20s if your any higher than 1,000 or so feet.

 

What you should do is talk to dlnoss (dave @ noss machine) and he'll give you all the info you want and set you up with the right sizes for your application. He's a great guy to work with and will get you setup right.

[dlnoss]

Like they said, stock is about 23cc.

 

What is the elevation where you ride? Is the timing advanced? What kind of gas are you running or wanting to run? Stock porting?

[racer]

at ls i get away with 19's. but im gonna start mixin my shit 50/50 pump/race.

[bigboybanshee]

Is the timing advanced? 

285150[/snapback]

 

Does advanced timing cause an increase in compression? I know this has been asked before but what compression is high enough to require race gas? Isn't it like at 170 you need to run race fuel; or is it lower than that?

[wesw]

more timing equal more a chance of detanation or pinging, which higher compression. say you put some domes in like 19 and test your compression and it is 160psi then you throw in +4 you probably will need more octane to handle it

[bigboybanshee]

In theory, if I were at 148 psi and I throw a +4 degree key on there, do you think I'd be OK on 93 octane pump gas?

 

Don't mean to hijack this thread, these questions could answer other possible questions about dome sizes/compression, etc...