top end compression question?

[BlasterMaster15]

i just got my cylinder bored to .050 and just installed the piston yesterday. i have not started it yet since i dont have my reeds yet and whehn i tested my compression without the reed cage or carb on it was about 125. is this good? will it be higher once it is broken in or is this a good compression?

 

[JonS]

you should do it with the cage in for a more accurate reading.

 

[99LRDblaster]

i just got my cylinder bored to .050 and just installed the piston yesterday. i have not started it yet since i dont have my reeds yet and whehn i tested my compression without the reed cage or carb on it was about 125. is this good? will it be higher once it is broken in or is this a good compression?

It's perfectly fine. It will go up about another 10psi or so once the rings are seated in the cylinder and get rid of blow by through the rings. I don't think testing without the reeds would hurt much......a compression test at this point is worthless though. You want to know what it will be once you get the rings seated. Good baseline to start with though. Now you can do a leakdown test and make sure everything is sealed up. From there you can start breaking it in and if you want, do a compression test each after each break in session(let the engine cool completely) and you will begin to see the compression go up as the rings seat. Once the compression stops going up, that's when you know the engine is more or less broken in as far as the rings go.

 

[UncagedShadow]

a leakdown test would be more important at this time than a comp test. You want to find any leaks that could potentially kill your motor before worrying about the comp.

 

[theblasterboy]

^^smart or youll be right back at block 1