Cylinder Replacement Issue

[Larry Trotter]

I am sort of thinking you have some other issue. Seems that you may be fixated on something that is not the problem. It is very easy to do. Step back and look at every other thing that could make it not run. Change plugs, it can have spark with no compression on it but fail under compression. Larry

 

[Dead66]

I am sort of thinking you have some other issue. Seems that you may be fixated on something that is not the problem. It is very easy to do. Step back and look at every other thing that could make it not run. Change plugs, it can have spark with no compression on it but fail under compression. Larry

You seem to be correct. I replaced the spark plug and the gas at the same time so I don't know which it was. But it is now running. I have, I think 3 gaskets at the bottom and one at the top. I had just enough time to run around the block. It is not running well. but it runs. Will not get up to really good speed... With the head off and the cylinder torqued down, the top outer edge of the piston was maybe a mm or 1.5mm below the top of the cylinder.

Also, the bottom of piston shows just a bit looking through the intake at top of stroke.

Maybe I should remove a gasket?

Also, was running without muffler. What effect does that have?

Thanks all for putting up with me

 

[Larry Trotter]

When you raise the cylinder you change the port timing on all 3 ports at once, just adding head gaskets will leave the port timing alone.

 

[Dead66]

When you raise the cylinder you change the port timing on all 3 ports at once, just adding head gaskets will leave the port timing alone.

And you think I can get away with using two head gaskets?


BTW, I finally located the guy who sold me the original motor. He can send me a matching PK80 cylinder. But he wants $45 shipped or $75 shipped if he ports it. Seems steep to me, no?

This one appears to be a better match than what I have. The bottom picture shows the cylinder as 81mm tall just like mine.

Advice on what to do next?

 

[Larry Trotter]

I would try two head gaskets before I paid $45. I just found an ebay auction for a whole engine kit for $50.00 delivered.

 

[crassius]

this is where the forum doesn't help a lot - some things are hard to tell about without getting 'hands on'

piston sounds like it is in right place in cylinder - compression test would tell more

 

[Dead66]

OK, I am gonna try it with one less gasket on bottom and two on top.

Trial and error you see...

 

[Dead66]

I removed on lower gasket tonight but did not have to add an additional one to the head gasket. Ran pretty well actually. At the moment I am not sure if I will bother getting another cylinder or not. I am now going to concentrate on attaching my Poo Poo muffler which I bought to replace the rigid one that I hit and cause it to break the original cylinder. It looks like I will need to do some welding possibly to get this poo poo muffler to mount right. Once I do that I will see how the new cylinder is working out.

Anybody know anything about these poo poo mufflers with flexible extensions on them?