Dominator piston clearance?

I have only worked on four twin motors,three had siezed at some time on the drive side. John Hudson advised me to allow four and a half thou skirt clearance on a 600 . No problem since then but the motors were not as quiet as some I have heard.Bore finish needs to be matched up with ring spec .Don't powder coat cylinders or use slotted skirt old pistons.

There is a video of an experiment testing effect of powdercoat on access norton forum using a heating element in the bore and temp sensors on outside. Result was that powdercoating is as good as high temp paint for heat removal. I can confirm as I have been powercoating barrels for 20 odd years with no ill effects.

http://www.accessnorton.com/barrel-coatings-test-t21701.html

Video

https://youtu.be/dJEgo4Fego8

Interesting read. At no point was the test tried on a bike, In the real world powdercoat thickness is variable. Was the temps tested on a tight bore on a motorway in summer at 60 mph stuck behind an artic in dead air. Its just another variable risk I don't need.

I'm not the expert you need, but my understanding is that the bore finish needs to match the ring spec in that a finely honed finish will not bed in properly if used with some rings and the angle of the cut of the final finish is also important. You need to do some research. My 99 was rebored and honed to a fine finish , After thousands of miles of normal classic use it was not fully run in, It took a few flat out sessions on race tracks and the IOM to devellop full compression and the crankcase breathing to stabilise.