while breaking in a fresh engin at around 75 miles i lost a cylinder due to ignition failure resulting in overheating new engine,my stupidity. I later ran a compression test,135 lbs front 125 lbs rear.this is on an 88 ci buell std heads red shift 585 cams 263 duration 580 lift j&e pistons at around 10 to 1 static compression. what do you think ? is this normal with this set up or do i need to tear it down and re-ring. thanks al

 

If you only have 100 miles on the engine I think those numbers look pretty good. I'd keep going and keep the throttle open but not wide open for another couple hundred miles and check comp again.

 

When you did the test did you have the throttle wide open?

 

cylinder presure should be in the 175 to 180 range.

my bike is just over 10.2, and its 195

 

throttle wide open yes i just hate to put this back in with the cranking pressure that low

 

I would fire it up, see if it rattles at all, warm it up a little, shut it off and do a leak down test, and take it from there. Warm, around 5-7% would probably be about right. If more, and air is hissing out of cases or oil bag, rings are needed.

 

I was 190/190 stock and 180/180 after cams "37's".

 

can't fire it up motor is on the bench , what abought a cold leak down test any figures in mind ? thanks al

 

Cold, say 10-12% max assuming rings are not fully seated yet. Listen for where the air is escapping, that will tell the story.

 

appreciate the input ,it will be a day or so before i can get back on it , i will throw up some numbers as soon as i can , thanks again . al