Quote Originally Posted by rsterne View Post
.... but quickly grew tired of pumping it....
Bob
I didn't think I was ever going to see an admission like that from you. Things always change-up, though

I've melted a delrin piston, or six, trying to force the 13-XX beyond what it's designed for. It can be done. It's my opinion that the current crop of aluminum 13-XX valves are poor candidates for volume expansion via the boring and cutting method. A thread-in spacer between the valve halves would be a stronger solution- at the cost of swept volume. A longer pump tube pretty well becomes a prerequisite...

Regards,

Doc Sharptail