It seems I've now bored and honed a lot of cylinders over my lifetime. All types of pistons (cast iron cylinders). Clearances from .001-.002 or .0015-.002 or .002-.003 or .0035 to .0045 and all types of other weird combinations. The bigger the piston, the more clearance, unless it's made of bla bla bla bla . . . there are so many different combinations of materials, sizes and finish. It's really a delicate balance. Get the bore straight and the correct surface finish (60 degree cross hatch) . . . It's the most important part of the motorcycle engine(of any engine) - it's this cylinder and piston combination that endures the heat, the speed, the force, the fuel, the oil, the wear . . . it makes the power. If overlooked and not done correctly - performance and reliability will suffer.
Pure art. It takes a true experienced craftsman to do that stuff correctly...
ReplyDeleteWithout all the modern equipment (I use a Van Norman 900 Boring Bar (patent date 1933) you just have to measure 2 and 3 times, see where it bored, where to center it in an out-of-round cylinder. I call it "finesse" with everything. All cast-iron cylinders are not created equal either - some soft, some hard - Rebuilding 1930s, 40s, 50s, engines with equipment from the same era. It's really pretty cool.
ReplyDeleteI guess my dad could have been a sewing machine mechanic - and I'd be fixin' vintage Singers (not that there's anything wrong with that)
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