1975 Honda CB200T Compression Issue

[yonson88]

Hello all!! I just recently took apart my motor, replacing piston rings, all gaskets, adjusted the timing, and adjusted the tappets. After all of this, I am still only getting 80psi from each side the same. If I add oil down the spark plug hole, they both got to around 115psi. How can this be with brand new rings?
A little history, the bike was purchased with One hundred and nineteen original miles, how clean the air boxes were and inside of engine confirms this. Only issue, the engine was frozen. I got it unfroze but figured I damaged the piston rings in the process as the compression was 80 on right and 70 on left. After everything was cleaned and new piston rings were installed as well as gaskets and fresh oil, compression is now 80 on either side. This is way low. Im not sure where to go from here or what else I may check. I am at the point were I want to just buy a good compression motor for the bike but good luck with that!
Thank you for your help, any comments are helpful!
Eric

 

[Sonreir]

Did you have the cylinders honed and/or bored?

 

[carnivorous chicken]

Valves.

 

[yonson88]

I know that they cleaned the cylinders, did not bore out, wouldn't that mean you would have to go to over-sized rings?
I planned to have it honed but they didnt have one that small. Did it by hand, cleaned it up real good.
I will check valves, make sure they are seating correctly, we did do a leak test and was under 20 percent.. around 17.
Is that normal?

 

[Sonreir]

8% to 12% is the usual "good" numbers. Lower is better and performance engines usually shoot for under 5%.

Measure the bore on the cylinders and check it against the service manual. This will tell you whether or not need you need the cylinders bored. This isn't something you can just eye ball and make a decision.

Also, double-check the valve lash. Clearances too low will result in low compression readings.

Finally, perform an acetone test on the valves. Get the head off the motor and place it upside down on a level surface. Fill each combustion chamber with acetone and wait five minutes. Any leakage past the valves is unacceptable.

 

[yonson88]

Thank you, Your help is much appreciated!!

 

[yonson88]

Ok, so I talked to a few motorcycle experts and one told me to open the tappets to a gap of .015 rather then .002, not to run on but just for the compression test to be sure the valves were closing all the way. After doing this the compression stayed the same 80. I tracked down another compression tester. My buddy had a real nice snap-on one. Sure enough after putting the tappets back to the correct .002 and testing with his gauge, the left side read 150 and right 160. All I have left now is to tune and sync the carbs. Thanks for all the input and knowledge.