Jaystre Posted December 19, 2010 Report Share Posted December 19, 2010 I check my compression after the rebuild ,new pistons, new crank and my gauge reads 190 !! im running cool head with 21 cc dome at sea level and 4 mill crank. if anybody who has a similar setup could let me know what kind of readings they have ... trying to rule out a faulty gauge . Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted December 20, 2010 Report Share Posted December 20, 2010 I check my compression after the rebuild ,new pistons, new crank and my gauge reads 190 !! im running cool head with 21 cc dome at sea level and 4 mill crank. if anybody who has a similar setup could let me know what kind of readings they have ... trying to rule out a faulty gauge . faulty guage... Quote Link to comment Share on other sites More sharing options...
TwistedSheeRida Posted December 20, 2010 Report Share Posted December 20, 2010 More info on your top end setup, are you running the cometic top end for the long rod crank or thick base gasket? 185psi on mine last year fresh build cometic top end gasket kit 4mm long rod wisecos 21cc domes 285ft above sea level. .046 squish. Its possible i ran 100ll pretty much all year in it at first i ran cam 2 110 Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted December 20, 2010 Report Share Posted December 20, 2010 no porting or what? Quote Link to comment Share on other sites More sharing options...
AKheathen Posted December 20, 2010 Report Share Posted December 20, 2010 no porting or what? x2........21cc's should kick some high compression, but un-ported with recessed domes, and bore size can bump it quite a bit. what's your info? Quote Link to comment Share on other sites More sharing options...
Jaystre Posted December 20, 2010 Author Report Share Posted December 20, 2010 cylinders are unported 65mm bore ,its a long rod crank and a spacer plate between the head /cylinder ... would this cause detonation? Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted December 20, 2010 Report Share Posted December 20, 2010 You can do it both ways his kit probably came with a 2mm spacer with the double head gasket riveted too it.with that compression you need at least 108 octane or better.If you already have the cool head try selling your domes and picking up 22cc stroker domes and ditch the plate.The number for fast racing is in my sig he can send you them no problem.I have seen people mess there cylinder decks up from running both spacer plate and coolhead together.The spacer is made for an OEM head so if you have your stock head laying around use that with your spacer and it should kick around 135-140 and be safe for pump gas 91-93 octane Quote Link to comment Share on other sites More sharing options...
Jaystre Posted December 20, 2010 Author Report Share Posted December 20, 2010 so 22 cc stroker domes would be good enough to run pump gas ... Quote Link to comment Share on other sites More sharing options...
AKheathen Posted December 21, 2010 Report Share Posted December 21, 2010 so 22 cc stroker domes would be good enough to run pump gas ... omho, no....with an unported 66mm bore and -2mm deck, you would need 24-25 to push pump. 23, would be a far streatch for 93 and stock timing..... i would bolt the stock head on and see what ou get, then cc it and get domes based on those readings..... Quote Link to comment Share on other sites More sharing options...
Jaystre Posted December 21, 2010 Author Report Share Posted December 21, 2010 ill have to double check the compression then ,i dont have the stock head bike came this way. It seems to run fine .I can advance timing if that can help? i find it strange that i could not run a coolhead ?? Quote Link to comment Share on other sites More sharing options...
Jaystre Posted December 21, 2010 Author Report Share Posted December 21, 2010 how can i be sure its pre-detonating ...what are the usual signs ? Quote Link to comment Share on other sites More sharing options...
Jaystre Posted December 21, 2010 Author Report Share Posted December 21, 2010 can porting change compression readings ? i know my port timing isnt right because im not using a spacer plate underneath the cylinders .i see a lot of people on here running 21 cc domes or smaller . whats the biggest size domes available ? Quote Link to comment Share on other sites More sharing options...
WynoT Posted December 22, 2010 Report Share Posted December 22, 2010 OEM Head is 24cc I've seen a lot of 21 and 22cc dome, not sure for 23 but probably exist somewhere... Quote Link to comment Share on other sites More sharing options...
AKheathen Posted December 22, 2010 Report Share Posted December 22, 2010 no timing advance will cause it to predet even worse. you can retard the timing. predet is a retarded word already...... oh, and stock heads range 23-25cc, usually, and yes, you can get 24, 25 etc domes for your coolhead.....they can custom cut just about anything for it. i just figured you would have your old stock head laying around.... Quote Link to comment Share on other sites More sharing options...
Jaystre Posted December 22, 2010 Author Report Share Posted December 22, 2010 yeah well it might be cheaper to buy a stock head after all . just triyng to get this right . Quote Link to comment Share on other sites More sharing options...
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