jumjum01
Registered
I have come to the conclusion that the piston rings has failed to seat on my 1441 bigbore hayabusa. The compression is only 200psi with stock cams and 12.88:1 CR. Spark plug threads are oily and when I applyed 14psi compressed air through spark plug hole, there is a lot of air exiting the crankcase breather hose. I did the compressed air test to both this 1441cc motor and my stock spare busa motor. The 1441 motor filled a 1 liter plastic bag with air completely in 3 minutes via the crankcase vent hose. The stock motor failed to the bag with air, stopped the stopwatch after 10 minutes.
The motor has done 2500kms after rebuild with bigbore and new pistons. I used 10/30W mineral oil for break-in, but did not realize that is was important to apply load and rpm during break-in. I drove it very gentle during the first tank of gas. Basically I the worst thing :-(
Now I will have to order new piston rings and head gasket. Do the cyilnders need a re-hone??
The motor has done 2500kms after rebuild with bigbore and new pistons. I used 10/30W mineral oil for break-in, but did not realize that is was important to apply load and rpm during break-in. I drove it very gentle during the first tank of gas. Basically I the worst thing :-(
Now I will have to order new piston rings and head gasket. Do the cyilnders need a re-hone??