700vflash Posted April 16, 2011 Report Share Posted April 16, 2011 I had a stock head with .030 shaved off and now I just installed a fast cool head with 20's. Before I had my idle just high enough to keep the shee running and now when I pushed the choke in it cuts off. I have only run it for a few moments but it seems like I need to bump the idle up a bit. So I am wondering if that is normal? Quote Link to comment Share on other sites More sharing options...
Nutwood 472 Posted April 16, 2011 Report Share Posted April 16, 2011 I had a stock head with .030 shaved off and now I just installed a fast cool head with 20's. Before I had my idle just high enough to keep the shee running and now when I pushed the choke in it cuts off. I have only run it for a few moments but it seems like I need to bump the idle up a bit. So I am wondering if that is normal? Did you a compresion test after the cool head,if so whats the psi? Quote Link to comment Share on other sites More sharing options...
700vflash Posted April 16, 2011 Author Report Share Posted April 16, 2011 I haven't done a compression test yet, waiting to use a buddy's tester. I am going to do a compression test on it before I go rippin on it, but I am just wondering if it is common to bump up your idle when you raise your compression. I am at sea level here in Florida, I have read with the 20's I should be somewhere around 160-170 psi, is that right? Quote Link to comment Share on other sites More sharing options...
Nutwood 472 Posted April 16, 2011 Report Share Posted April 16, 2011 I haven't done a compression test yet, waiting to use a buddy's tester. I am going to do a compression test on it before I go rippin on it, but I am just wondering if it is common to bump up your idle when you raise your compression. I am at sea level here in Florida, I have read with the 20's I should be somewhere around 160-170 psi, is that right? what kind of fuel are you running,when you bump up your comp,your idle should get better i thuoght,do your test to see if you have a leak on domes before you ride imo Quote Link to comment Share on other sites More sharing options...
700vflash Posted April 16, 2011 Author Report Share Posted April 16, 2011 I have 100 octane av gas in it now. I have only let it run for a few minutes, but I don't see any leaks. Quote Link to comment Share on other sites More sharing options...
Nutwood 472 Posted April 16, 2011 Report Share Posted April 16, 2011 I have 100 octane av gas in it now. I have only let it run for a few minutes, but I don't see any leaks. its better safe than sorry man,i would take off radiator cap,so it doesnt build pressure,so orings heat up and seal with no pressure on them,since they are new, Quote Link to comment Share on other sites More sharing options...
700vflash Posted April 17, 2011 Author Report Share Posted April 17, 2011 Well I couldn't wait on a pressure tester, so I got my own. The motor dosn't seem to be 100% so I did the compression test with the motor cold and the throttle wide open and got 210 on the left and 209 on the right. This is much higher than I was expecting and not sure if my fuel has a high enough octane rating or not. Please, any knowledge of octane or compression related info is needed!!!! Quote Link to comment Share on other sites More sharing options...
Coupelx Posted April 17, 2011 Report Share Posted April 17, 2011 thats an engine killer right there. Quote Link to comment Share on other sites More sharing options...
700vflash Posted April 17, 2011 Author Report Share Posted April 17, 2011 Engine killer? Quote Link to comment Share on other sites More sharing options...
700vflash Posted April 17, 2011 Author Report Share Posted April 17, 2011 Well after much reading I have gathered that the high compression will give me more power, but will not rev out as high. My crank is welded and I ride primarily trails, so I think I will try this set up for a little while. But the down side is I aslo have to run the 110 octane, which here it is at $8.50 a gallon! Quote Link to comment Share on other sites More sharing options...
Coupelx Posted April 17, 2011 Report Share Posted April 17, 2011 to really know your octane requirements you need to figure out your compression ratio. with that said, that much compression even with race gas is a waiting disaster. there is really no reason to run that much compression and it will beat the shit out of your bearings and pistons. I think there are better methods of getting power than stupid high compression myself especially since as you mentioned, race gas isnt exactly cheap. Quote Link to comment Share on other sites More sharing options...
700vflash Posted April 17, 2011 Author Report Share Posted April 17, 2011 Didn't think of it at the time, but I believe my vito pistons are the reason my compression is so high! I will probably end up changing my domes a few times before I find the right one's, but I will at least try these while I have them installed. I understand that it will add extra stress on the motor, but I have faith in my fresh buld! Quote Link to comment Share on other sites More sharing options...
Coupelx Posted April 17, 2011 Report Share Posted April 17, 2011 Quote Link to comment Share on other sites More sharing options...
700vflash Posted April 18, 2011 Author Report Share Posted April 18, 2011 What size do ya think? I am at 210 psi with 20's, maybe 22's would be about 180 psi? Quote Link to comment Share on other sites More sharing options...
Glenyboy Posted April 18, 2011 Report Share Posted April 18, 2011 Call fast who you got your head off of I'm sure they'll be able help you out Quote Link to comment Share on other sites More sharing options...
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