jbooker82 Posted March 19, 2010 Report Share Posted March 19, 2010 Really? You need higher octane with +4 timing?? No you can get away with +4 timing and 150 psi of compression on pump premium fuel. I think this guys gauge is off and he is really over the limit. That is why he is having detonation and plugs backing out. josh Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted March 19, 2010 Report Share Posted March 19, 2010 Well its a brand new Lisle gauge (its what the parts store had it was like 50 bucks) but im not sure just how accurate it is i dont hear any deto but i might not know just what to listen for either What does the end that threads in to the spark plug hole look like? Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted March 19, 2010 Report Share Posted March 19, 2010 If it looks like this one then that is your problem. Any air space that is before the shrader valve in the end of the hose is added volume to your combustion chamber. There for you dont get an accurate reading. This explains it all. http://bansheehq.com/forums/index.php?showtopic=70901&view=&hl=compression gauge&fromsearch=1 Quote Link to comment Share on other sites More sharing options...
sheeban Posted March 19, 2010 Author Report Share Posted March 19, 2010 If it looks like this one then that is your problem. Any air space that is before the shrader valve in the end of the hose is added volume to your combustion chamber. There for you dont get an accurate reading. This explains it all. http://bansheehq.com/forums/index.php?showtopic=70901&view=&hl=compression gauge&fromsearch=1 Yep thats the gauge i bought why do i have to use the long thread adapter could i just screw the gauge in with out the adapter i have not tried that yet Quote Link to comment Share on other sites More sharing options...
sheeban Posted March 19, 2010 Author Report Share Posted March 19, 2010 Never mind that i guess it would do same thing by not threading in as far as the plug making more volume = less compresion, bummer i wasted fifty bucks on a cheap gauge Quote Link to comment Share on other sites More sharing options...
SAVAGE420 Posted March 19, 2010 Report Share Posted March 19, 2010 Never mind that i guess it would do same thing by not threading in as far as the plug making more volume = less compresion, bummer i wasted fifty bucks on a cheap gauge Yeah you want the adepter threads to be the same exact length as the spark plug threads will be. This tester i have came with a few different size and lengths to check different stuff. You could grab an adapter for yours i bet. Quote Link to comment Share on other sites More sharing options...
Burt Reynolds Posted March 19, 2010 Report Share Posted March 19, 2010 Really? You need higher octane with +4 timing?? Im saying this should be obvious,he switched from 100 to 91 and now his plugs are backing out. Im not trying to uncover a breaking story here. Static compression shouldnt be used for more than to keep an eye on the life of an engine. I have seen motors that need 115 octane only putting out 150 psi of static compression because they have two seasons on them and are wearing out. Its all about compression ratio. So someone might think "damn i dont need a rebuild i still got 150 psi" when in actuality their motor is about to explode lol. So in my opinion it doesnt matter to me if my auto zone tester is 10 psi off from what the actual psi is,as long as it consistent to itself. Like in the case of seeing if there is more of a 10psi difference between cylinders. Like if it reads 10psi over i want it to always read 10 psi over and not jump around Detonation can be loud or subtle. It can blow away large chunks,or microscopic pieces. It can rip out cylinder and head studs too. In my old 250r,when i had it rebuilt my machinist guy said i need to bump up the octane a tad because of detonation,and i told him i didnt see any marks on the old piston or head,well then he had to get out a magnifying glass to see it. right now im running 93 octane on 150psi,and +4 timing and doing fine so every quad is different too. Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted March 19, 2010 Report Share Posted March 19, 2010 Yeah you want the adepter threads to be the same exact length as the spark plug threads will be. This tester i have came with a few different size and lengths to check different stuff. You could grab an adapter for yours i bet. His does have the long thread adaptor, but the broblem is the adaptor has a long hole that goes up to the schrader valve in the main adaptor. That long tube also adds volume. Click the link there are pic's explaining. josh Quote Link to comment Share on other sites More sharing options...
Burt Reynolds Posted March 19, 2010 Report Share Posted March 19, 2010 No you can get away with +4 timing and 150 psi of compression on pump premium fuel. I think this guys gauge is off and he is really over the limit. That is why he is having detonation and plugs backing out. josh I am running +4 timing with 150 psi static compression on 93 octane with no problems. Its actualy one of the the stronger running stock port bikes i have have been on. Im probably getting away with it because i dont have a high compression ratio,or my autozone tester is off lol but if his bike ran fine on 100ll then didnt on 91 octane i would say its obvious his problem is his fuel Quote Link to comment Share on other sites More sharing options...
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