Just read a post that referred to the compression on a 89 pilot being 130 cold and 120 hot, and needing a rebuild. What should the compression run on one? Reason for asking is that after a fresh rebuild and now with probably 20 hrs riding, that is what I am reading. This was also my reading right after the rebuild. Does this mean theres something wrong?
Rooky

At what elevation are you testing your compression?

You try it with another gage perhaps your gage is not calibrated?


What was your piston to cylinder clearance and ring end gap?

I am probably 500ft. elevation. As far as ring gap and clearances, don't have a clue. I let the other guy do all the measuring and micing when he bored it. I just put it together and ride. How can I test my guage? Not a snap-on, but it is brand new.

You have a friend that has another gage you can try?

I do have access to another guage, but it may take a couple days to get my hands on it. I did check my guage by using air pressure and an air guage that I know to be accurate, and the comp. guage checked ok doing this.
Still would like to hear from other pilot owners and what they read on their stock pilots. I can't find a psi reading in the manual, only ratios. Can these ratios be converted to psi?

You should always measure your piston and rings before you install to ensure they
are correct..


Take a look at your compression tester there will be a valve core at or near the end
of the hose, that is the check valve, it needs to be as close to the piston as you can
get, you don't want to include any volume past the end of the tester hose where it
screws into the spark plug hole, adding volume in the hose will lower your reading
because there is a increase in the trapped volume.

So where is your valve core located?

Did you have the throttle open all the way? If not you won't be allowing enough air to get into the cylinder to get an accurate reading. I've found that many of the gauges that you can buy at sears etc. are not even close to being accurate even when they are new.

manual states 149 -156 lbs. psi

The valve core is seperatde from the piston only by the adapter that screws into the plug hole,and no I did not have the throttle wide open when I checked it, but I will try tomorrow again. This guage was $49.99 at Auto Zone, so I can't expect alot.
I have performed leak down test and there are no leaks, and the compression reads the same now as it did after I rebuilt the top about 10hrs ago. If there is a compression problem such as a bad ring, wouldn't the Engine loose compression with riding time? Can I find a bit of hope in the fact that my readings haven't changed any since the rebuild?
Thanks
Rooky

What cylinder bore are you on? If the jug has been bored several times the compression volume will get larger and compression readings will get lower. Did you use honda gaskets during the rebuild? I'm not sure about other manufacturers, but if the head gasket was thicker for some reason it would also lower the compression.

The bore is at 81mm. As far as gaskets, I am not sure what type they are. Looked like the OEM but I didn't take any thickness measurements on it.