Coleman CT200u-ex quits on full throttle - stage 2

[Gordy]

Replace that with a regular old spark plug. I tried running an E3 in my mini bike, but it just would get fouled constantly. I don't think it's supposed to be reading that low on compression. It's supposed to read a lot higher even with the compression release on the cam.

 

[alexi]

Replace that with a regular old spark plug. I tried running an E3 in my mini bike, but it just would get fouled constantly. I don't think it's supposed to be reading that low on compression. It's supposed to read a lot higher even with the compression release on the cam.

I'll replace the plug, drive it, and test the plug. Low compression, would that be the rings?

 

[alexi]

I'll replace the plug, drive it, and test the plug. Low compression, would that be the rings?

I checked the lash on the valves, I'm like at .012 and .013, which is out of spec. I'll see if that changes anything after I set them to .003.

 

[alexi]

I checked the lash on the valves, I'm like at .012 and .013, which is out of spec. I'll see if that changes anything after I set them to .003.

This is what the piston looks like

 

[Gordy]

I'll replace the plug, drive it, and test the plug. Low compression, would that be the rings?

My guess is rings or valve seats. Did adjusting the valves help any?

 

[Chainlube]

I'll replace the plug, drive it, and test the plug. Low compression, would that be the rings?

How many times do you pull the rope when checking the compression?

 

[Gordy]

How many times do you pull the rope when checking the compression?

I didn't even think about that. You're supposed to pull a handful of times until the gauge stays in one spot.

 

[alexi]

I'm replacing the crank from 5/8 to 3/4 and will test it with proper valve lash. I pulled a handful of times and it stopped a little over 60psi. I'll try again once assembled and then try adding a little oil to see if it makes a difference.

 

[Wrench]

Coleman ct200u compression should at least be 130psi - that's the minimum

It will still run with lower compression, but not very good

 

[darwin]

The piston looks new in the pics, the rings too. Has to be the valves somehow. Gasket or crack in the block.