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Piston sizes

Posted: Tue Jul 01, 2014 1:11 pm
by jimyboyle
While in the middle of my 2 door restoration, I bought a 1275 midget engine to fit in place of my 1098.

The internals look quite good, big ends have been ground to -.010" and the bores show almost no wear however,
the pistons are clearly marked 0.75 suggesting 75 thou rebore.

When I measure the bores I get about 71.4mm (metric mike) which is 0.030"over standard

Would piston have been incorrectly marked? seems hard to believe.

Jim

Re: Piston sizes

Posted: Tue Jul 01, 2014 4:24 pm
by katy
I don't know if it means anything, but .75mm = .0295275"

Re: Piston sizes

Posted: Tue Jul 01, 2014 9:49 pm
by jimyboyle
Well spotted Katy, it never crossed my mind that they could have marked the piston with a metric unit
Jim