Compression issues on fresh KOR bored cylinder

[Bodyshopmike]

Well here is where I am in my full rebuild. Everything has been assembled and when I initially tried to start the old girl I was only getting between 60-65 psi. I pulled the cylinder and sent it off to Ken O'Connor. Ken bored it to the next size and sent me it back with a new Wiseco piston and new gaskets. I installed everything Thursday night and let it sit until this morning to let everything settle and the Yamabond sealant dry. Well I put some gas in the tank and kicked, kicked and kicked until I was drenched in sweat. I pulled the plug and installed my compression tester. Kicked 10 times and it's only reading 50 psi now. My leak down held at 7 psi for over 5 minutes. I need a starting point now. I am soooo close to getting this thing finished and was hoping someone could give me some direction as I have also sent Ken an email but I don't want to call him on the weekend. Any help would be greatly appreciated.

Thanks guys,
Mike

 

[Bluesman]

Did you buy your compression gauge at harbor freight? They have been known to read about 60 lbs on all engines.

I hope you put oil on the cylinder when you assembled it.

 

[Larry's Shee]

Ya, start with trying another gauge.

 

[joeak47]

Try using a "quality gauge", and be sure to hold the throttle WIDE OPEN while doing the test. A closed throttle will completely bugger up the test, because its not getting any air in the cylinder.

 

[Blaaster]

Did you check for spark?

Is everything assembled?

Is the float level correct?

Could the plug be fouled with assembly oil?

Could the plug lead be faulty from pulling it off?

 

[Bodyshopmike]

Did you buy your compression gauge at harbor freight? They have been known to read about 60 lbs on all engines.

I hope you put oil on the cylinder when you assembled it.

I did. Going to pick up a different one today.

 

[Bodyshopmike]

Did you buy your compression gauge at harbor freight? They have been known to read about 60 lbs on all engines.

I hope you put oil on the cylinder when you assembled it.

Assembled everything with Yamalube two stroke oil.

 

[Bodyshopmike]

Ya, start with trying another gauge.

Picked up the new gauge and it's now registering over 120 psi.

 

[Bodyshopmike]

Did you check for spark?

Is everything assembled?

Is the float level correct?

Could the plug be fouled with assembly oil?

Could the plug lead be faulty from pulling it off?

Tank with fuel is just temporarily screwed on.
I checked the float level when I rebuilt the carb.
Going to check for spark now.

 

[Bodyshopmike]

Well pulled the spark plug boot off, cut 1/2" of insulator off and reinstalled. She fired up!!!! Now the tuning begins. Thanks for the help everyone!!!!

 

[Bluesman]

Awesome! Now take that Harbor Freight compression gauge out in the driveway and smash it with a big hammer.

Once I had an ink jet printer that was giving problems. I had it repaired at a local printer shop. A month later it was doing the same thing. I yanked the cords out of it, took it outside, and threw it up in the air as high as I could. It came down on the sidewalk and smashed into a bunch of pieces. I picked up the pieces and told my secretary, "The printers broken. We need a new printer".

 

[joeak47]

Awesome! Now take that Harbor Freight compression gauge out in the driveway and smash it with a big hammer.

Once I had an ink jet printer that was giving problems. I had it repaired at a local printer shop. A month later it was doing the same thing. I yanked the cords out of it, took it outside, and threw it up in the air as high as I could. It came down on the sidewalk and smashed into a bunch of pieces. I picked up the pieces and told my secretary, "The printers broken. We need a new printer".

Now that's funny!

 

[Herpderplol]

That reminded me of this

 

[jus_me]

After the rings seat your comp should go up a bit.

 

[joeak47]

Well... Did you re-test with the throttle open?