Just had my cyclinders ported, after breaking it in I did a compression check to find I only had a 100 pounds in each cyclinder. Before the porting I had about 130 pounds. I had the cyclinders bored and honed and put new wiseco's in. Used all new gaskets when putting it back together. Anyone have any ideas where or how to start looking for lost compression? Or is it normal to have less compression after porting? Oh yeah I have a prodesign head with 21cc domes.

Thanks in advance
David Chapman

 

when you raise the ports it drops the compresion go with a lower cc dome to bring it back up you might want to call the company that ported your cylinders to find out what cc domes to go to