Re: Norton fork damping plug
I do not believe there is significant variation in the miss placed hole size in the damper tube taper as the Convent Kit with the Al peg plugs fit my '72 and many others just fine for decades now. Even it they didn't fit that great its a non issue when you beat them in place and don't need to mess with smoothing down the finish as nothing encounters or slide fits over the damper tube taper. Also as sloppy as other clearances in forks are, a tiny leak out the plugs, like Ms Peel's fabulous forks, would also be a non issue to silent bottoming and rebound. Might review your forks operation as the damper tube holes are only meant to control bottoming at shortest fork length.
Its the hole in the fork tubes the top bush should cover up on full extension for silent soft stop, like Peel's. My method was to allow forks to expand enough the factory bushes covered the fork tube holes plus with these 2" more inches of expansion, top out stop is hardly ever needed to function unless in rough off road play. Might look at moving the fork tube holes so they block off before reaching the factory spring rest length w/o any extra collar. That surface seal finish would matter of course but not as much as my leaky damper plugs as there's only the spring force expanding forks not bike/pilot force landing on speeding impacts.
