An unusual cl/cb72 cylinder block

Dick Eastman · Post by **Dick Eastman** » Thu Jan 07, 2016 9:34 pm

A friend stopped by wanting me to measure his 250 bores: they were about 2.207" or 56mm. The stock bore is 54mm. I thought over bores on these were only 1mm o/s or 55mm.
Can anyone offer info on this?

rrietman · Post by **rrietman** » Fri Jan 08, 2016 12:03 am

I have a cb72 bored 3mm over. you can buy pistons all day long up to 4-5mm over. the liners get a little thin up there but it's doable.
Randy

honda brian · Post by **honda brian** » Fri Jan 08, 2016 5:28 pm

Hi Dick, I built an engine with a 2mm overbore. I believe the pistons were CB250. (56mm). Hope this helps.
Brian.

Dick Eastman · Post by **Dick Eastman** » Sat Jan 09, 2016 8:34 am

honda brian wrote:Hi Dick, I built an engine with a 2mm overbore. I believe the pistons were CB250. (56mm). Hope this helps.
Brian.

Thanks. I did see a set of 3mm over on e-bay - a 276cc kit, Japanese mfr.
Dick

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An unusual cl/cb72 cylinder block

An unusual cl/cb72 cylinder block