turbowrenchhead Posted May 24, 2014 Report Share Posted May 24, 2014 I have a stock stroke and 66mm pro lite pistons with stock ported heads. Noss head w/ 22cc domes. I recently changed out the cylinders and pistons. The cylinders were decked .004 because of a nick in the head. I'm using a .015 base gasket and my squish is at .045 with that. I was told between .040 & .050 is optimal. I did a cc fluid check and I get 15cc's in the chamber with 22cc domes. By method of a online calculator(http://www.cbperformance.com/v/enginecalc.html) I get a cranking compression of 160psi. That puts me at 14.5:1 compression. Way to high for pump gas. 23cc domes would lower my cranking and my uccr compression. The thicker the base gasket I use will increase my squish. Then I'm out of the optimal range. If I run the .031 base it will drop compression to 12.5:1 but increase my squish to.061. Last year I didn't know my uccr but my cranking compression was 150psi with 21cc domes, stock base gasket (.026) and undecked heads. The bike ran great last year and even ran a tank of 87 octane in it with no problems. The pistons didn't show any signs of detention either. Quote Link to comment Share on other sites More sharing options...
Coupelx Posted May 24, 2014 Report Share Posted May 24, 2014 i would quit half assing shit and have some domes cut for it. if it only took .004 to clean up a scratch i woulda filled it with jb weld and ran the fucker. Quote Link to comment Share on other sites More sharing options...
turbowrenchhead Posted May 24, 2014 Author Report Share Posted May 24, 2014 Don't have time to cut domes for it. Big trip of the year is 7 days. Quote Link to comment Share on other sites More sharing options...
Coupelx Posted May 24, 2014 Report Share Posted May 24, 2014 have you bothered to call anyone? Quote Link to comment Share on other sites More sharing options...
turbowrenchhead Posted May 24, 2014 Author Report Share Posted May 24, 2014 I just found this out tonight. Whom might I call? Quote Link to comment Share on other sites More sharing options...
BANSHEE HP Posted May 24, 2014 Report Share Posted May 24, 2014 .020 base gasket and run 93 octane Quote Link to comment Share on other sites More sharing options...
oldskool Posted May 24, 2014 Report Share Posted May 24, 2014 more octane, go ride Quote Link to comment Share on other sites More sharing options...
SAVAGE420 Posted May 24, 2014 Report Share Posted May 24, 2014 Drill a small hole in tops of pistons . =) 1 Quote Link to comment Share on other sites More sharing options...
turbowrenchhead Posted May 24, 2014 Author Report Share Posted May 24, 2014 I'm lucky if they have 91 octane in the rural areas I go riding in. We go on 100 mile rides. Usually we head to a town 40~50 miles away, fill up and head back Quote Link to comment Share on other sites More sharing options...
Coupelx Posted May 24, 2014 Report Share Posted May 24, 2014 I'd start with noss machine seeing as domes are what he does... Quote Link to comment Share on other sites More sharing options...
turbowrenchhead Posted May 24, 2014 Author Report Share Posted May 24, 2014 I emailed him last night and left a message this morning. I will need them by Thursday next week or I'll have to go with bigger base gaskets. Quote Link to comment Share on other sites More sharing options...
m671054 Posted May 24, 2014 Report Share Posted May 24, 2014 Bigger base gasket = higher exh port duration. Quote Link to comment Share on other sites More sharing options...
turbowrenchhead Posted May 24, 2014 Author Report Share Posted May 24, 2014 Bigger base gasket = higher exh port duration. Yes I know Quote Link to comment Share on other sites More sharing options...
J-Madd Posted May 24, 2014 Report Share Posted May 24, 2014 You can usually get domes from Noss in a couple of days. Quote Link to comment Share on other sites More sharing options...
WINDYCITYJOHN400 Posted May 24, 2014 Report Share Posted May 24, 2014 Don't have time to cut domes for it. Big trip of the year is 7 days. This is the price of earning late in the game. Run a thicker base gasket for now. The squish will open up....but that's better than too tight or too much compression. Maximizing power for a long trail ride doesn't seem to be a big priority. Not to mention the need to get jetting established for this new motor........ Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.