HardIzZlE Posted November 10, 2007 Report Share Posted November 10, 2007 i just got a new compression tester & im going to use it on the shee but i just wanted 2 know want is a good psi for my bike it is bored .20 over & also can some 1 give me a quick summary on how many times to kick it & if it should be done on a hot motor thx Quote Link to comment Share on other sites More sharing options...
shee4speed Posted November 10, 2007 Report Share Posted November 10, 2007 Stock head? whats your elevation? About 30 kicks.Cold motor is okay. Quote Link to comment Share on other sites More sharing options...
bansheefreak Posted November 10, 2007 Report Share Posted November 10, 2007 hold throttle wide open and kick it till the needle stops moving.. main thing you wanna see is both cyls close to same psi .. the bored 20 over dont mean shit.. Quote Link to comment Share on other sites More sharing options...
BellicoseBanshee Posted November 10, 2007 Report Share Posted November 10, 2007 (edited) i just got a new compression tester & im going to use it on the shee but i just wanted 2 know want is a good psi for my bike it is bored .20 over & also can some 1 give me a quick summary on how many times to kick it & if it should be done on a hot motor thx Cold motor Throttle wide open 15-20 kicks 3 tests per cylinder 5-10 minutes between tests A fresh stock reading is around 120-130, depending on elevation...the main thing is to make sure the cylinders have about the same compression reading. Others might do it differently... EDIT: they beat me to it... :laugh: Edited November 10, 2007 by BellicoseBanshee Quote Link to comment Share on other sites More sharing options...
Coupelx Posted November 10, 2007 Report Share Posted November 10, 2007 i like to let mine run for a few seconds (no more than a minute) to ensure everything is freed up and in working condition. Pull both plugs hook up guage hold throttle open kick till the needle stops going up theres no point in kicking it more note reading rinse and repeat! readings will very as to if the engine is cold (or close to it) or at operating temps. consistancy is the key though. Quote Link to comment Share on other sites More sharing options...
blowit Posted November 10, 2007 Report Share Posted November 10, 2007 the bored 20 over dont mean shit.. Contraire young one. Bigger bore means a higher comp ratio for constant head volume. It does not equal much in this circumstance but does matter. The banshee is so friggin embarrassing on comp ratio, a little more will do nothing but help. Brandon Quote Link to comment Share on other sites More sharing options...
bansheefreak Posted November 10, 2007 Report Share Posted November 10, 2007 Contraire young one. Bigger bore means a higher comp ratio for constant head volume. It does not equal much in this circumstance but does matter. The banshee is so friggin embarrassing on comp ratio, a little more will do nothing but help. Brandon well my point was 20 over/stock/ 100over your compression should be over 110 to 120lbs anyways.. and each cyl should be close to same readings... so basically when your doing a compression check the info on the bore is not needed.. but i may be wrong.. correct me if i am.. cus all the 20over tells me is there is room to grow.. if compresion is low.. Quote Link to comment Share on other sites More sharing options...
blowit Posted November 10, 2007 Report Share Posted November 10, 2007 well my point was 20 over/stock/ 100over your compression should be over 110 to 120lbs anyways.. and each cyl should be close to same readings... so basically when your doing a compression check the info on the bore is not needed.. but i may be wrong.. correct me if i am.. cus all the 20over tells me is there is room to grow.. if compresion is low.. Lets just say that with basically stock trim motors, you will grow maybe 15psi between 64-biggest over bore. This becomes more critical with race motors and strokers. Hell, 1cc difference on one of our 7mm motors can change the ratio I think 8:1. Anyway, it does make a difference but not enough to really matter on a stocker. The ratio is good to know for estimating static pumping numbers and problems. You are right, static pressure balance is a must. we allow 5-7psi delta here and that is it. Brandon Quote Link to comment Share on other sites More sharing options...
HardIzZlE Posted November 10, 2007 Author Report Share Posted November 10, 2007 so while im doing the test shoild i leave 1 spark plug in or take no Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted November 10, 2007 Report Share Posted November 10, 2007 Take them both out. Quote Link to comment Share on other sites More sharing options...
black sunshine Posted November 10, 2007 Report Share Posted November 10, 2007 I usually leave one in the other hole just to keep out foreign stuff while all that kicking is going on. It doesn't affect the readings. Quote Link to comment Share on other sites More sharing options...
HardIzZlE Posted November 10, 2007 Author Report Share Posted November 10, 2007 i just did a test on each cyl & they both came out 75 psi i did a cold & a hot test & 1 test cold test i left 1 plug in & another cold test took the other plug out same for the hot test....but my bike starts up 4-5 kicks cold in cold weather & still runs like a beast & the tester is brand new first time used (got it from fraigh harbor lol) so you guys think just keep on rideing her? cuz i really dont have the extra $$$ 2 put a new top end in& she still rides good ps: i hear a noice when the bike is ideling (not that loud) coming from the cyl`s im pretty sure its piston slap. is a tiny bit of slap ok? thx Quote Link to comment Share on other sites More sharing options...
blowit Posted November 10, 2007 Report Share Posted November 10, 2007 i just did a test on each cyl & they both came out 75 psi i did a cold & a hot test & 1 test cold test i left 1 plug in & another cold test took the other plug out same for the hot test....but my bike starts up 4-5 kicks cold in cold weather & still runs like a beast & the tester is brand new first time used (got it from fraigh harbor lol) so you guys think just keep on rideing her? cuz i really dont have the extra $$$ 2 put a new top end in& she still rides good ps: i hear a noice when the bike is ideling (not that loud) coming from the cyl`s im pretty sure its piston slap. is a tiny bit of slap ok? thx Do what you want. Most do anyway but 75 is an alarming number. Post a pic of the harbor junk you bought. It is very possible that its only reading about 80lbs off accurate or so. That would be inline for harbor junk. If they only made surgeon tools so doctors could get a hook up too. Anyway, have it tested by a real tester for verification and I have posted this about 100 times now but compression does NOT mean your engine is good!!!! Piston slap will never show up on a comp test. If you decided to ride a slapper, go ahead and call the bank and get pre-approved for a loan to cover a new crank, and maybe some new cylinders when it pops. Sorry to rant. Brandon Quote Link to comment Share on other sites More sharing options...
HardIzZlE Posted November 11, 2007 Author Report Share Posted November 11, 2007 my moms camara dont work so i can take pics but this is the 1 i got http://www.harborfreight.com/cpi/ctaf/disp...temnumber=39224 Quote Link to comment Share on other sites More sharing options...
black sunshine Posted November 11, 2007 Report Share Posted November 11, 2007 I would really recommend checking it with another tester that is known to be accurate. I have gone through this the hard way with a buddies Matco that was well taken care of. That one told me I was at 80psi in both cyls but the bike fired up in the first two kicks all the time. This is usually uncharacteristic of a bike with that compression. Got a bore and new pistons and 20cc domes and the tester read 100psi!!!! Got a Snap-On and got 160psi both cyls, which is right where it should be. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.