stoopidfast Posted May 20, 2015 Report Share Posted May 20, 2015 (edited) I my having problems with my plugs coming out. I am 4 degrees advanced timing and 18cc domes. Something isn't right though, I thought I would be have much higher compression then 140PSI in each cylinder. Would my altitude of 2165' have anything to do with that low compression. Everywhere I have read, it says detonation is probably the main cause for this. The 18cc domes I have are just scribed in the side, where the 23cc domes I have are stamped. This makes me weary of the 18cc domes. I took the cool head off last night and everything looks good, no pitting or internal damage. Any suggestions or guidance would be greatly appreciated. Thanks. Edited May 20, 2015 by stoopidfast Quote Link to comment Share on other sites More sharing options...
98_sheester Posted May 20, 2015 Report Share Posted May 20, 2015 Are the coming out while ride or you mean with a wrench Quote Link to comment Share on other sites More sharing options...
Rigid_Banshee Posted May 20, 2015 Report Share Posted May 20, 2015 I've heard the same thing about plugs backing themsleves out...detonation is probably a factor here Quote Link to comment Share on other sites More sharing options...
stoopidfast Posted May 20, 2015 Author Report Share Posted May 20, 2015 They are coming out while riding. Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted May 20, 2015 Report Share Posted May 20, 2015 Detonation backs plugs out. Ditch those 18cc domes asap. 1 Quote Link to comment Share on other sites More sharing options...
stoopidfast Posted May 20, 2015 Author Report Share Posted May 20, 2015 plugs don't just back out. Yes, they do just back out. I know they are not supposed to. I am trying to figure the issue before something expensive happens. I am not sure if it is detonation or some other issue... Quote Link to comment Share on other sites More sharing options...
stoopidfast Posted May 20, 2015 Author Report Share Posted May 20, 2015 Detonation backs plugs out. Ditch those 18cc domes asap. Which size ahould I be running? I am surprised at my low compression with those domes. Do I want to go higher or lower compression? Quote Link to comment Share on other sites More sharing options...
98_sheester Posted May 20, 2015 Report Share Posted May 20, 2015 18cc should be on race gas Quote Link to comment Share on other sites More sharing options...
Bennett131 Posted May 20, 2015 Report Share Posted May 20, 2015 You said you got 140psi per cylinder, I suggest trying another compression tester first of all. Do you have any porting? 1 Quote Link to comment Share on other sites More sharing options...
special06shee Posted May 20, 2015 Report Share Posted May 20, 2015 You said you got 140psi per cylinder, I suggest trying another compression tester first of all. Do you have any porting?this. Its not uncommon for cheap compression testers to be misleading. Ive had brand new ones,(junk) read completely off the wall. Quote Link to comment Share on other sites More sharing options...
Bennett131 Posted May 20, 2015 Report Share Posted May 20, 2015 Harbor freight FTW Quote Link to comment Share on other sites More sharing options...
stoopidfast Posted May 20, 2015 Author Report Share Posted May 20, 2015 You said you got 140psi per cylinder, I suggest trying another compression tester first of all. Do you have any porting? Yes, I have a KICK ASS quite aggressive port job from Kevin @ Herr Jugs Racing. I will buy a better compression tester. The Canadian Tire one I have is quite old. Thanks. Quote Link to comment Share on other sites More sharing options...
Bennett131 Posted May 20, 2015 Report Share Posted May 20, 2015 Porting will give you a lower reading, and if youre buying a new compression tester id go with Mac or Snap On. Quote Link to comment Share on other sites More sharing options...
stoopidfast Posted May 20, 2015 Author Report Share Posted May 20, 2015 Porting will give you a lower reading, and if youre buying a new compression tester id go with Mac or Snap On. Got a call in to my local Snap On and Mac dealers. Thanks. Quote Link to comment Share on other sites More sharing options...
Bennett131 Posted May 20, 2015 Report Share Posted May 20, 2015 Just put a plug lock on . It'll keep em from coming out !HA! Quote Link to comment Share on other sites More sharing options...
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