Can anyone recommend an inexpensive compression tester My 1980 IT125 seems a...

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Can anyone recommend an inexpensive compression tester? My 1980 IT125 seems a bit low on compression... it's VERY easy to kick.. yet it doesn't start unless I FUCKIN STOMP ON IT.. then it starts in 2 kicks.. but my son and wife cannot start it. (they can't kick it hard or fast enough. (another clue: you can push start it in 2nd gear with no one pushing.... just use your feet Flinstone style and in literally 6 feet, let out the clutch and it will start right up .. and it idles great... and.. what should the compression be?

%d comments
  • I borrowed my neighbors...but you could rent one from Autozone or O'Reillys. I can tell you that if it's REALLY easy to kick, it's gonna need a top end rebuild anyway, and if you can move the crank without moving the piston, it will need a bottom end bearing also.

  • If you can bump it flintstones style while sitting on the bike it's time for a new topend lol.

    My 81 was very easy to kick, but you could still feel the compression.

  • Go up a size on the pilot jet, warm it up and then set the pilot air screw, hopefully it'll idle smooth when the air screw is about 1 - 3/4 turns out from the bottom. She may start better cold then.

    Have you done a leak down test to see if the intake isn't leaking air? Yes.. a compression test would also be good to do.

  • I would think most auto parts store would have a compression tester. Just make sure it has the proper adapter to fit the IT's spark plug hole. I don't have the IT spec in front of me, but I should think it will be in the 150PSI range. They do make cheaper compression testers that don't thread into the spark plug hole, they have a rubber seal that you push tightly against the spark plug hole. With this type of tester it's tough to get a good seal and it now takes two people to do the test.

  • He really should do a compression test before attacking the jetting. It's a waste of time jetting for a worn topend...

  • Does it blow your thumb off of the spark plug whole?

  • Harbor Freight sells a decent one for not much money. It's often on sale too!

    http://t.harborfreight.com/compression-test-kit-8- pc-62638.html

  • Cool Tom. thanks!

  • $25 seems more than fair.

  • Yeah certainly.. I totally agree but why not at least try to rule out jetting first? If that fixes it, then he saves time! (And of course the reverse is also true.. to your point..)

  • Besides, I figured you actually needed an intelligent answer.