Last weekend, tired of making excuses to myself as to why I haven't started the engine rebuild on the racer project, you know, the one I was gonna finish by Christmas.............
Anyway, I had a nice set of stock cylinders that i needed to bore from 61mm to 65mm for the 836cc Wiseco pistons. I'm lucky enough to have my own boring bar in my garage, a "loan" from my cousin 2 years ago, it's an old "Repco" (Aussies will know the brand) small engine boring machine, lovely simple old thing, if a little slow, my cuz told me that the max cut per pass was not to exceed 10 thou, or about .25mm, which meant I was looking down the barrell (pun intended) at a staggering 16 passes per cylinder, or a total of 64 passes! At a couple of minutes per pass, that equates to several hours work. Bummer.
What a pain in the ass! After each pass I'd clean the bore with compressed air and a rag, then use an internal micrometer to measure the bore diameter, and plot my progress for each pass. Sadly it's an old machine, so it's necessary to keep an eye on it, all the while spraying or dripping cutting fluid (kerosene/diesel mix seems to work pretty good, as does diluted soluble cutting oil, which is cheaper) into the cylinder to keep the cutting tool lubed and cool.
Anyway, I accidentally adjusted the cutter to 20 thou, and took a cut, and it cut fine! Hmmmnnnnn, so I took another cut, fine again and I'd removed one full mm of metal in 2 passes! Woohoo! I kept going, then as I got into the 64's, I reduced the cut back to 10 thou, then 5 thou, so as to get a nice clean finish, with minimal honing required. Trouble was, once again I miscalculated the adjustment for the last cut, and instead of having a nice 65mm bore, I've got an unfinished 65.125mm bore, so I'm screwed! (Mental note to Terry: Measure twice, cut once!)
