A CB250 twin restorer ( he sold the NOS tank and paintwork set on eBay recently) and has an 100% immaculate restored K4 model, advised me that I will find it difficult to locate standard size piston rings as surprisingly they are rare. He says that that he uses +0.25mm oversize rings and just gaps them accordingly in the standard bore. I have the option on 8 sets on +0.25 Genuine Honda ring sets at 20% of the CMSNL last listed price, so if it is indeed an acceptable practice, I will buy a few sets. Personally, I have never heard of it before but he says it's common practice amongst pro. engine builders.
Ash
