August 2, 200917 yr Bit of a novice and could do with a bit of help - I posted yesterday ref my Fantic frame but now i've found something else - The engine bottom end has a plate that says it's a FM 250 125cc. Took the head off and noticed that the piston looked bigger than the 55mm or so that it should be. Measured it and it's 62mm which gives a capacity of 156cc. Knowing that Fantic made a 156cc I did a bit of looking round and it appears that many 125 & 156 bits are the same so I presume that this started out life as a 125 and someone's put a 156 block and piston on it. Question - The carb is a Delorto 24mm. Is that right for the 156 or is it the old 125 carb (or are they the same anyway?)? I also have a 26mm Delorto. Will this be any better? There's 3 cylinder head gaskets in there too. Is this right or is it someones attempts to alter the compression ratio??? Advice on jetting for whichever carb would be appreciated too. Ta, Steve
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.