Quote: do you have a tank or are you in need of one?
I have the metal tank I ordered a couple of weeks ago, the one with the "out-dent" section on which I had planned to put the old WWII Army Air Corps star/bar.
The problem is which one to choose. The metal tank will require a slight
modification to the frame backbone ... yep, cut & weld. The foam tank has been carved to fit the frame of course, but I will need to do fiberglass it, cut the holes for the cap and pet-thingy, dissolve the foam from inside, install the cap and pet-thingy and seal the tank. At this point it seems that the cut/weld for the metal tank would be less work.
If I go with the metal tank then the bike will be a bobber style, whereas if I go with the fiberglass tank then it will be more of a flat tracker/cafe racer style.
Also, since the metal tank was damaged when I received it, I will have to wait for a replacement. There is plenty of work to be done and keep me busy though.
The exhaust port, on the outside where the header bolts up, is 36x38mm. I removed some material from the wall just inside the port and rounded/smoothed the top of it. Some material was also remove from each of the two valve passages just before they merge into the port. From the valve seat, the near side radius is carefully rounded/smoothed and polished a little. I spent some time with some machine shop guys discussing the theory's of porting. I picked up a few ideas that make the job a bit easier to do well.
I had wanted to go larger on the valve size but decided it was not necessary for a street bike. The exhaust valve passageways are the bottleneck in this head so I focused on them instead.
There is no blue coating inside the port, that is just reflection from a blue colored mat.
And yes, once you get to grinding on the metal it is fun and hard to stop. There is always one more spot ...
The foam tank is supposed to be patterned after a BSA Goldstar racing tank.