mich169 Posted June 26, 2011 Report Share Posted June 26, 2011 Just wondering how much compression for a 4 mill stock cylinder stock head bike should have ??? Quote Link to comment Share on other sites More sharing options...
shanYE west Posted June 26, 2011 Report Share Posted June 26, 2011 Just wondering how much compression for a 4 mill stock cylinder stock head bike should have ??? depends.. anywhere from 150-190.. alot of variable. Quote Link to comment Share on other sites More sharing options...
Phelps Posted June 26, 2011 Report Share Posted June 26, 2011 mine is 180. Quote Link to comment Share on other sites More sharing options...
mich169 Posted June 26, 2011 Author Report Share Posted June 26, 2011 Mines like 75 with brand new pistons on both cylinders Quote Link to comment Share on other sites More sharing options...
shanYE west Posted June 26, 2011 Report Share Posted June 26, 2011 sounds like you have a problem.. whats your setup and what domes and pistons? Quote Link to comment Share on other sites More sharing options...
mich169 Posted June 26, 2011 Author Report Share Posted June 26, 2011 I got to take it a part I had some1 put it together for me the head and cylinders r stock I got .058 of clearance if that helps. Is there a way to get the compression up ? Quote Link to comment Share on other sites More sharing options...
mich169 Posted June 26, 2011 Author Report Share Posted June 26, 2011 Any1 Quote Link to comment Share on other sites More sharing options...
mich169 Posted June 26, 2011 Author Report Share Posted June 26, 2011 Can I have my head cut to make more compression? Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted June 27, 2011 Report Share Posted June 27, 2011 Mich , i think guys arent answering because they have absolutely no info as to what you have other than a 4mm stock cyl. If its a stock cyl with a stock head you can either lowere the cylinder and head with a thinner base gasket or have the head milled and raise the compression. Both those things do different things to power and compression. It really depends on what the motor really is. A motor with 90 psi may just be wore out, but we have no info. Also a motor with 90psi will barely start. Quote Link to comment Share on other sites More sharing options...
springer Posted June 27, 2011 Report Share Posted June 27, 2011 there are things you can do to raise the compression, but if you are only at 75, you have a problem that needs to be fixed before you do anything like shaving the head or playing with gaskets. maybe the wrong size of gasket was used to begin with, in that case, just switch it out for the proper one. Quote Link to comment Share on other sites More sharing options...
lms1977 Posted July 1, 2011 Report Share Posted July 1, 2011 Yea if its all new 75lbs is not good something is wrong. I would pull it apart and check it pc by pc maybe wrong pistons or rings? hope you figure it out. Quote Link to comment Share on other sites More sharing options...
Surfrjag Posted July 1, 2011 Report Share Posted July 1, 2011 are you sure the tester is sealed and working properly and have kicked it over untill the needle on the tester stops? your compression sould be higher than that without lowering the head. i would say an easy 125 if the bike runs ok Quote Link to comment Share on other sites More sharing options...
camatv Posted August 4, 2011 Report Share Posted August 4, 2011 if the bike starts and runs its not 75lbs of comp after about 90 they wont kick start anymore. who built it? maybe you should go talk to them.. if its just some buddy you paid with beer or cheese burgers that might be your problem. .58 is pretty loose on squish also but 75lbs is really low// Quote Link to comment Share on other sites More sharing options...
shanYE west Posted August 4, 2011 Report Share Posted August 4, 2011 if the bike starts and runs its not 75lbs of comp after about 90 they wont kick start anymore. who built it? maybe you should go talk to them.. if its just some buddy you paid with beer or cheese burgers that might be your problem. .58 is pretty loose on squish also but 75lbs is really low// way to go and dig this one up Cam.. you must have gotten bored.. lol Quote Link to comment Share on other sites More sharing options...
camatv Posted August 6, 2011 Report Share Posted August 6, 2011 what the hell this was on the front page man we need some NEW threads!!! this old shit is fuckin boring!! Quote Link to comment Share on other sites More sharing options...
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