hollisatp Posted November 20, 2008 Report Share Posted November 20, 2008 What dome size is comparable to having a stock head milled .004 ?? Is it 21 or 22? Thanks for the help.. Quote Link to comment Share on other sites More sharing options...
hollisatp Posted November 20, 2008 Author Report Share Posted November 20, 2008 maybe I worded the question wrong? Does anyone know what the smallest cc dome I can use but still run on pump gas? Quote Link to comment Share on other sites More sharing options...
deckheight Posted November 20, 2008 Report Share Posted November 20, 2008 General consensus for O-ring domes is 20cc on fresh 92+ octane fuel. Quote Link to comment Share on other sites More sharing options...
hollisatp Posted November 20, 2008 Author Report Share Posted November 20, 2008 Thanks! That would be the lowest cc right?! Quote Link to comment Share on other sites More sharing options...
deckheight Posted November 21, 2008 Report Share Posted November 21, 2008 Could go a little smaller, but things tend to get a little sticky if you know what I mean. Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted November 21, 2008 Report Share Posted November 21, 2008 Depens on what elevation you ride at and if your machine has bee ported. If your running a stock port at sea lever I would stick with 21cc. At sea lever with 20cc domes your going to be at aroudn 169-170 psi. Too much for pump fuel. Now if your rideing at 1000 ft 20cc domes woudl put you at 156 psi wich would probably be ok depending on what your timing is set at. http://www.nossmachine.com/banshee_heads.htm Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted November 21, 2008 Report Share Posted November 21, 2008 Then again you can run 16cc domes on pump fuel at 5000 ft above sea level. The are supose to be at 151 psi at that altitude. If you ran 16cc at sea level you would be at 217 psi. Quote Link to comment Share on other sites More sharing options...
hollisatp Posted November 21, 2008 Author Report Share Posted November 21, 2008 well.. check my mods.. i am thinking 21cc domes would be safe all around.... everyone agree?? Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted November 23, 2008 Report Share Posted November 23, 2008 well if your at sea leve then 21's is what I woudl run. If your were around 2000 ft then I would go with 20's Quote Link to comment Share on other sites More sharing options...
deckheight Posted November 23, 2008 Report Share Posted November 23, 2008 We consistently run 20cc domes, T-5's and +2 timing at sea level all day long on fresh 92 octane fuel. The motors I have disassembled showed no signs of excessive combustion chamber temps or detonation. Go figure! Obviously, certain things have an effect... things like high gearing or other constant heavy loads, bizzaro ignition curves, really efficient pipes, etc. could very well be problems. Don't know... Nothing wrong with using a little caution however... Especially if a person cannot seem to keep fresh, good quality fuel in the tank! BTW, when you guys talk elevation above sea level... I assume your referring to relative air density. Where I ride the best air quality I probably ever see is at sea level, 65 deg ambient air temp, 60% relative humidity. Quote Link to comment Share on other sites More sharing options...
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