Hi Bess,
I am having problems with the exhaust valve on my B31 and shortly I want to get the head reamed and if necessary fit an over size guide
So the dimensions you have given are of great interest, but can I ask you to double check?
The outside diameter of a standard exhaust valve is 5/8" (15.875mm)?
But what is the diameter of the hole to accommodate the guide including tolerances?
Thanks in advance,
Chris