Results 1 to 8 of 8

Thread: i think my compression tester is lieing to me

  1. #1
    troy's Avatar
    troy is offline At The Back Of The Pack Arm chair racerAt the back of the pack
    Join Date
    Aug 2006
    Location
    Canada
    --
    254

    Cool i think my compression tester is lieing to me

    Said in one other post I made about 2 days ago I was having problems starting my Honda 200ES. And when I would get it to start it ran badly. And a 5 year could pull it over . I did the compression test heres the results..

    With no oil in the cylinder (tested the way she stopped):

    - 60psi closed throttle
    - 120psi WOT

    With oil in the the cylinder (added by me)
    -90psi closed throttle
    120psi WOT


    Now of course with those results I was not happy as most of you wouldn't be. So off with the head and wall and away I went. I replaced the rings with newer ones I bought for a older projected the ended up cancelled, and (don't yell at me) reused the old gaskets of course after cleaning them up and inspected them closely. I clean up the head and wall (where the two meet) and put it all back together. Set the timing which may or may not be right. I match the 0 of the cam sprocket to the top of the valve head, and the T on the fly wheel was showing dead in the middle of the timing window. NOW where I think the tester is lying. When I did the test heres the results.

    120 psi WOT.....BUT the bike is ten times harder to pull over then before.

    So any ideas what’s going on? I haven't got the bike completely together because it was getting late and work calls for me tomorrow.

    thanks
    Last edited by troy; 06-10-2007 at 09:38 PM.

  2. #2
    Join Date
    Jan 2007
    Location
    Back in Happy Valley
    --
    833
    If you're a tooth or two retarted on one or another the fire will be late enough that it will combust as the piston starts to return to the top causing it to be harder to pull. On a car this would be the 'kicking' the starter thats often refered to when trying to set time the 'quick' way...
    86 350X
    85 350X daily rider
    LC 250R
    85 T3
    86 T3 roller
    85 250sx beater



  3. #3
    troy's Avatar
    troy is offline At The Back Of The Pack Arm chair racerAt the back of the pack
    Join Date
    Aug 2006
    Location
    Canada
    --
    254
    Quote Originally Posted by i58829 View Post
    If you're a tooth or two retarted on one or another the fire will be late enough that it will combust as the piston starts to return to the top causing it to be harder to pull. On a car this would be the 'kicking' the starter thats often refered to when trying to set time the 'quick' way...
    LOL....heres the thing. I just pulled it over, there no cdi or any ignition setup on it yet. Just the carb and exhaust and spark plug with nothing hooked up to it

  4. #4
    Join Date
    Jan 2007
    Location
    Back in Happy Valley
    --
    833
    Well it could be way out of time, a V8 will still act the same way because the compression is in the cyl. and will be trapped there due to bad timing whether its firing or not. If the air is getting compressed by the piston and the valves aren't open when they need to be the pressure will be felt by the starter (your arm in this case). Try it without the plug and see what happens...
    86 350X
    85 350X daily rider
    LC 250R
    85 T3
    86 T3 roller
    85 250sx beater



  5. #5
    troy's Avatar
    troy is offline At The Back Of The Pack Arm chair racerAt the back of the pack
    Join Date
    Aug 2006
    Location
    Canada
    --
    254
    see thats the thing every thing match's the service manual spec's. T in the timing window and 0 mark on the cam sproket at the top. but like you said and i did notice with my ERN 1 tooth makes for a problem

  6. #6
    Join Date
    Apr 2006
    Location
    Crestview, Florida
    --
    2,429
    You should check compression on a warm engine otherwise your #'s will be low. And crank it over a few times.

  7. #7
    Join Date
    Jan 2007
    Location
    Utah
    --
    644
    MY '81 ATC200 (185) has 120psi with WOT. I cant remember if it was warmed up or not though, I think it was. However, I am 5280 feet above sea level and my bike smokes quite a bit.
    It says you should have you bike at an operating temperature to get an accurate compression reading. This is becuase when hot, the rings will expand and create a tighter seal. 120psi is enough for a bike to run on. You should be fine with this compression.
    A few wheelers, + an
    '73 Honda 49cc Mini Trail
    '85 200 Big WHEEL

    "Despite the cost of living, its still popular."

  8. #8
    Join Date
    Nov 2006
    Location
    southern oregon
    --
    2,338
    Quote Originally Posted by troy View Post
    120 psi WOT.....BUT the bike is ten times harder to pull over then before.

    So any ideas what’s going on?
    You may have the exact same ring seal as before.... and the extra drag you feel is just the added ring tension from the newer rings.... But most likely your guage just has a bad valve.... that can only trap 120 psi... most testers just use a standard schrader valve core... a simple fix...
    2-stroke lover

//ArrowChat Integreation Code //