Lost comp after rebuild

[Maul]

Just got bike back together, I had sent my cylinders to cascade innovations and got them ported and rehoned so I threw a new set of rings in there. Right after rebuild before I even fired it I had 105 lbs of compression. I went ahead and did three heat cycles and ran it down the road once. Now it only has 95 lbs. Also the head has been shaved .20 WTF is going on here I swear this bike has a curse.

[slopoke]

ck the ring end gap and let us know what it is. Is it a good guage?

 

[blowit]

ck the ring end gap and let us know what it is. Is it a good guage?

 

 

 

Probably a combination of things. A: Your comp gauge is probably lying to you. B: as you port an engine, or should I say increase the duration, you will lose cranking compression. Depending on what Cascade did, you may need less head displacement.

 

Start with a better tester. What elevation are you?

 

 

 

 

B

[Maul]

Ring end gap was good. My elevation is 3600. Also the head has been shaved .20 so I should have made up for loosing any from the porting.

I'll see if I can round up another gauge and try that.

[blowit]

Ring end gap was good. My elevation is 3600. Also the head has been shaved .20 so I should have made up for loosing any from the porting.

I'll see if I can round up another gauge and try that.

 

 

How do you now you "made up for the porting" Was there any math done? Do you know your durations? Those are things that must be considered. I would say your elevation in combination with the gauge is causing an issue.

 

 

 

B

[Maul]

Well not exactly sure on haveing the head shaved made up fot the porting was just saying that if the comp went down a little from the porting maybee the head would have taken care of a little of that.

I don't know the durations it is supposed to be a dune, play port.