What is the normal compression for a scrambler 400. I don't know what the reading should be. I ran a compression check and it is 120. My scrambler is a 1999 and it is yet to have a new pistion and rings. All 2 strokes that I have rebuilt in the past, the compression was between 110 and 135 after a rebuild. I am guessing that 120 is good but just thought I would ask.

 

I have heard numerous times about how a stock piston will break.
People that build these 400's will tell you to get rid of the stock piston and replace it with a wiseco.

 

good compression but id pull that stock piston and throw the wiesco in for what its worth

 

I guess I need to put a new pistion and rigs in it. Just don't understand why if I got good readings.

 

The reason is because the weak point of these pistons is the skirt. If the skirt breaks you will need a motor. Even if you have good compression and its a 99 it would only cost about $80 for a wiseco then you dont have to ever worry about the skirt breaking.