Diesel_89 Posted February 17, 2015 Report Share Posted February 17, 2015 Needing advice, I have a 1996 banshee with stock stroke,stock cylinder bored 60 over,cool head with 21cc domes and .055 squish, 1000ft elevation.I have used two different compression gages and have 175psi in both cylinders.I've been running race fuel but am wanting to get back to pump gas. Everything I've read says I shouldn't have this high of compression with these mods.Any help would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted February 17, 2015 Report Share Posted February 17, 2015 Are you 100% sure 21cc? I've gotten less with 20 at sea level Quote Link to comment Share on other sites More sharing options...
Diesel_89 Posted February 17, 2015 Author Report Share Posted February 17, 2015 Yes I had 20cc domes and just installed 21cc that I got from FAST. I had 190psi with the 20cc domes. Quote Link to comment Share on other sites More sharing options...
Diesel_89 Posted February 17, 2015 Author Report Share Posted February 17, 2015 I'm 100 percent sure they are 21cc I just installed them Saturday morning. New to all this but do people mill cool heads? Quote Link to comment Share on other sites More sharing options...
Diesel_89 Posted February 17, 2015 Author Report Share Posted February 17, 2015 I traded for the bike in September, so hard to say what's all been done to it. I did forget to mention that it's plus 4° on the timing. Quote Link to comment Share on other sites More sharing options...
Diesel_89 Posted February 17, 2015 Author Report Share Posted February 17, 2015 The snap-on Guage I used measures .671in and the other gauge measures .521in both read 175psi. 1 Quote Link to comment Share on other sites More sharing options...
Diesel_89 Posted February 17, 2015 Author Report Share Posted February 17, 2015 Thanks gravel for your input, zilla the snap-on gauge I used measured exactly the same as my spark plugs. Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted February 17, 2015 Report Share Posted February 17, 2015 Have you done a squish test? Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted February 17, 2015 Report Share Posted February 17, 2015 Are they shelf stock domes, or something someone made? I can only see it that high if it's been decked. Quote Link to comment Share on other sites More sharing options...
Diesel_89 Posted February 17, 2015 Author Report Share Posted February 17, 2015 Clean up port at the most, squish was .055 Quote Link to comment Share on other sites More sharing options...
Diesel_89 Posted February 17, 2015 Author Report Share Posted February 17, 2015 The domes came from FAST racing. Not sure if my cylinders have been decked. Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted February 17, 2015 Report Share Posted February 17, 2015 If they were decked your squish would be tighter than .055 , can you cc the domes yourself , I use marvel mystery oil and a big medical syryng, static compression and uccr are diffrent tho , if you can calculate uccr with that dome it would give you better idea . I have ran 175 psi on pump but motor was set up for it with help from mull engineering, I would try giving him a call , maybe give him some measurements and see what he says Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted February 17, 2015 Report Share Posted February 17, 2015 Regardless, if your current set up is making that compression but current squish is ok, I would just send those out to Jeff and have him pull 3-4 CC's out to get it in to pump fuel territory. Quote Link to comment Share on other sites More sharing options...
Diesel_89 Posted February 17, 2015 Author Report Share Posted February 17, 2015 Okay thanks guys, I will talk to jeff and cody again. Quote Link to comment Share on other sites More sharing options...
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