Misssppelllleddd Posted July 16, 2009 Report Share Posted July 16, 2009 Ok I have confirmed a huge compression jump. And to all who have told me that it is not possible to jump up compression alot just after a break in....well....my Banshee proves otherwise. First at break in I did a compression test on my 'shee and it was pushing 185 lbs each cylinder. After break in I did another compression test and I started pushing 205 lbs of compression. I tried other comprresion guages such as Snap On and Accuguage and they both gave the same reading. After riding throughout the summer so far, I did another compression test today and now I'm pushing 220 lbs of compression. I just checked it with a brand new Craftsman compression guage and confirmed it with a Snap On and Accuguage. Now the question is this.....how the hell is this possible? How can it jump up 20 lbs of compression after a break in and 15 more after riding through the summer? :geek: My engine mods are: 4mil crank, Aggressive trail port (wildcard), Trinity head with 19cc domes, 795 series pistions, VF3 reeds, 1/4 inch reed spacers, Pro-Circuit Pipes, Trinity Stage IV 2 in 1 carb (33mm PWK), Quote Link to comment Share on other sites More sharing options...
TeamRealtreeHD Posted July 16, 2009 Report Share Posted July 16, 2009 I find that hard to believe... Quote Link to comment Share on other sites More sharing options...
sandman81 Posted July 16, 2009 Report Share Posted July 16, 2009 Ive seen that in automotive engine, the reason for that is because the rings seat and everything breaks itself in. Checking it warmed up and checking it cool can also give you different readings. Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted July 16, 2009 Report Share Posted July 16, 2009 How were you checking the compression? Was it the same way every time? I dont see what your stating actually happening. Quote Link to comment Share on other sites More sharing options...
slopoke Posted July 17, 2009 Report Share Posted July 17, 2009 Oil residue left over inside the cylinders will cause it to read really high. Like an oil with alot of castor will leave a heavier film than say yamalube 2r. Had it happen to me. went from 185 on new to 215 a week later. pulled the head and noticed the oil film. Cleaned it and rechecked it and wala back to 185 Quote Link to comment Share on other sites More sharing options...
GrMeyer Posted July 17, 2009 Report Share Posted July 17, 2009 where you checking it on a cold or warmed up motor? Quote Link to comment Share on other sites More sharing options...
Misssppelllleddd Posted July 17, 2009 Author Report Share Posted July 17, 2009 How were you checking the compression? Was it the same way every time? I dont see what your stating actually happening. I always warmed up the engine for about 10 minutes and then used a compression guage. Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted July 17, 2009 Report Share Posted July 17, 2009 Did you pull both plugs, and hold the throttle wide open every time as well? Quote Link to comment Share on other sites More sharing options...
DallasGDub Posted July 17, 2009 Report Share Posted July 17, 2009 Mine went from 145ish on fresh built motor that was only started and warmed up, to 153ish after break in and 5 hours of riding. Quote Link to comment Share on other sites More sharing options...
Misssppelllleddd Posted July 20, 2009 Author Report Share Posted July 20, 2009 Did you pull both plugs, and hold the throttle wide open every time as well? yes Quote Link to comment Share on other sites More sharing options...
Thewhite Posted July 21, 2009 Report Share Posted July 21, 2009 Mine go up from 142-144 to 156-157 with stock crank and 20cc dome after some rides. I also get some higher value when the engine is hot (only check when the motor was in break in). Quote Link to comment Share on other sites More sharing options...
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