going on the part numbers of the cylinder and exhaust the JAP engine is either a 'M'type one, or a 'CM'type two. Both engines have a bore of 46mm and stroke of 48mm, a cc of 79.7.they both have a Bletchley-type AB-1 carby.The M type has a wico-
I.1259 magneto,and the CM has a wico- FW.1269 magneto. a photo of the coil set up will tell the difference if you need it. regards, john
