Bansh-eman Posted March 17, 2008 Report Share Posted March 17, 2008 oh so you didnt have a problem with the piston in this set just the orings popping out? i am getting confused becasue there has been like 60 differant topics in this post Quote Link to comment Share on other sites More sharing options...
Hulio-mv Posted March 17, 2008 Author Report Share Posted March 17, 2008 oh so you didnt have a problem with the piston in this set just the orings popping out? i am getting confused becasue there has been like 60 differant topics in this post right just o-rings popping out all the other stuss has ben in reply to questions and trying togive more info so the good guys can help me. Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 17, 2008 Report Share Posted March 17, 2008 ok and your squish shouldnt be causing it being that far out, and your running a coolhead??? its possible that the domes or the jugs are not flat. but you said that they do NOT pop out at the same place everytime correct? Quote Link to comment Share on other sites More sharing options...
Hulio-mv Posted March 17, 2008 Author Report Share Posted March 17, 2008 as far as I can tell it is not the same place and it is a modquad head if it makes any difference I amnot sure if I put the same dome back on the same side either but both times I took it apart it has been the right dome ring -kickstart side Quote Link to comment Share on other sites More sharing options...
Hulio-mv Posted March 19, 2008 Author Report Share Posted March 19, 2008 no more hints on what to look for? Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 19, 2008 Report Share Posted March 19, 2008 sounds like something is warped or un-even Quote Link to comment Share on other sites More sharing options...
No Limit Powersports Posted March 19, 2008 Report Share Posted March 19, 2008 Assuming that your old cylinders were .100 over and your new cylinders are 64mm and you didnt change the domes size this could be the route of your problems. With the new cylinders being smaller you will have a smaller combustion area and more compression also did your old cylinders have any porting done to them? This would cause lower compression before and allow you to run this setup with pump gas. Right now you are way over the limit of safely running pump gas with your compression/timing combo. Sounds like to me and this is just my $.02 that you just have to much compression and timing for pump gas, keep in mind that there are many different varibles that can effect your compression like bore size, porting, squish, base gaskets, and how fresh the motor is just to name a few. This may be why you were okay before and not now, try lowering the compression by putting in a larger size dome and i would also consider getting the dome custom cut to fit your motor cause it sounds like your squish is a tad loose or you might try a thinner base gasket if available. Just my $.02 Andy M&M ATV Quote Link to comment Share on other sites More sharing options...
FasterThanU90 Posted March 20, 2008 Report Share Posted March 20, 2008 TEST YOUR RADIATOR CAP! AND COOLING SYSTEM! THIS IS YOUR PROBLEM. it should hold 18 psi for 1 minute and as far as aviation fuel "AV gas" it has antifreeze in it, and not for banshee... for high in sky airplane Quote Link to comment Share on other sites More sharing options...
No Limit Powersports Posted March 20, 2008 Report Share Posted March 20, 2008 Ive built bikes that have been running on AV gas for upwards of 5 years flawlessly, never had any problem with it plus its cheaper round $4.00 instead of $6-$7 for race fuel. Not sayin its the best but it will work and work good. Quote Link to comment Share on other sites More sharing options...
Hulio-mv Posted March 20, 2008 Author Report Share Posted March 20, 2008 Ok had my cap tested and it started blowing bubbles at 11-12. the clymer said 13.5 to 17.8 so if mine is less it shouldnt cause the prob I am having right? Called modquad and talked to Mike after a long talk he said that I should try 50/50 and see if that works any better. So when my new domes and o-rings get here I will try it and see how it goes. Thanks everyone for the help. and any more that may come Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 20, 2008 Report Share Posted March 20, 2008 (edited) that is correct, a cooling system not holding pressure will NOT cause your o rings to keep popping out. its something with your domes, head, or your jugs. Edited March 20, 2008 by Bansh-eman Quote Link to comment Share on other sites More sharing options...
FasterThanU90 Posted March 21, 2008 Report Share Posted March 21, 2008 I see kno way this is a comp. problem... his squish is near perfect.. this is a cooling system problem so focus on this we are going waaay off track your cap is bad its not within spec. your cap is not relieving pressure so its finding another place to relief itslef like your head o-rings... word replace it and it should solve your problem. Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 21, 2008 Report Share Posted March 21, 2008 (edited) your backwards... its not holding pressure and letting it out. the cap is not going to fix the problem. the problem is in either the dome/head or the jugs. Edited March 21, 2008 by Bansh-eman Quote Link to comment Share on other sites More sharing options...
Hulio-mv Posted April 5, 2008 Author Report Share Posted April 5, 2008 Ok after checking fuel options locally I decided not to put the 19cc domes in and ordered a set of 20cc domes just got them in and a cold compression test shows 155-160 each side still too much for pump gass right. maby i will order a set of 21cc :wallbash: Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted April 5, 2008 Report Share Posted April 5, 2008 Ok after checking fuel options locally I decided not to put the 19cc domes in and ordered a set of 20cc domes just got them in and a cold compression test shows 155-160 each side still too much for pump gass right. maby i will order a set of 21cc :wallbash: i personally would not run pump but i know there are several guys that do. it's ultimately up to you Quote Link to comment Share on other sites More sharing options...
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